[PATCHv23 00/16] Contiguous Memory Allocator

[PATCHv23 00/16] Contiguous Memory Allocator

[Marek Szyprowski]

Hi,

This is (yet another) quick update of CMA patches. I've rebased them
onto next-20120222 tree from
git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git and
fixed the bug pointed by Aaro Koskinen.

Best regards
Marek Szyprowski
Samsung Poland R&D Center

Links to previous versions of the patchset:
v22: <http://www.spinics.net/lists/linux-media/msg44370.html>
v21: <http://www.spinics.net/lists/linux-media/msg44155.html>
v20: <http://www.spinics.net/lists/linux-mm/msg29145.html>
v19: <http://www.spinics.net/lists/linux-mm/msg29145.html>
v18: <http://www.spinics.net/lists/linux-mm/msg28125.html>
v17: <http://www.spinics.net/lists/arm-kernel/msg148499.html>
v16: <http://www.spinics.net/lists/linux-mm/msg25066.html>
v15: <http://www.spinics.net/lists/linux-mm/msg23365.html>
v14: <http://www.spinics.net/lists/linux-media/msg36536.html>
v13: (internal, intentionally not released)
v12: <http://www.spinics.net/lists/linux-media/msg35674.html>
v11: <http://www.spinics.net/lists/linux-mm/msg21868.html>
v10: <http://www.spinics.net/lists/linux-mm/msg20761.html>
 v9: <http://article.gmane.org/gmane.linux.kernel.mm/60787>
 v8: <http://article.gmane.org/gmane.linux.kernel.mm/56855>
 v7: <http://article.gmane.org/gmane.linux.kernel.mm/55626>
 v6: <http://article.gmane.org/gmane.linux.kernel.mm/55626>
 v5: (intentionally left out as CMA v5 was identical to CMA v4)
 v4: <http://article.gmane.org/gmane.linux.kernel.mm/52010>
 v3: <http://article.gmane.org/gmane.linux.kernel.mm/51573>
 v2: <http://article.gmane.org/gmane.linux.kernel.mm/50986>
 v1: <http://article.gmane.org/gmane.linux.kernel.mm/50669>


Changelog:

v23:
    1. fixed bug spotted by Aaro Koskinen (incorrect check inside VM_BUG_ON)

    2. rebased onto next-20120222 tree from
       git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git 

v22:
    1. Fixed compilation break caused by missing fixup patch in v21

    2. Fixed typos in the comments

    3. Removed superfluous #include entries

v21:
    1. Fixed incorrect check which broke memory compaction code

    2. Fixed hacky and racy min_free_kbytes handling

    3. Added serialization patch to watermark calculation

    4. Fixed typos here and there in the comments

v20 and earlier - see previous patchsets.


Patches in this patchset:

Marek Szyprowski (6):
  mm: extract reclaim code from __alloc_pages_direct_reclaim()
  mm: trigger page reclaim in alloc_contig_range() to stabilise
    watermarks
  drivers: add Contiguous Memory Allocator
  X86: integrate CMA with DMA-mapping subsystem
  ARM: integrate CMA with DMA-mapping subsystem
  ARM: Samsung: use CMA for 2 memory banks for s5p-mfc device

Mel Gorman (1):
  mm: Serialize access to min_free_kbytes

Michal Nazarewicz (9):
  mm: page_alloc: remove trailing whitespace
  mm: compaction: introduce isolate_migratepages_range()
  mm: compaction: introduce map_pages()
  mm: compaction: introduce isolate_freepages_range()
  mm: compaction: export some of the functions
  mm: page_alloc: introduce alloc_contig_range()
  mm: page_alloc: change fallbacks array handling
  mm: mmzone: MIGRATE_CMA migration type added
  mm: page_isolation: MIGRATE_CMA isolation functions added

 Documentation/kernel-parameters.txt   |    9 +
 arch/Kconfig                          |    3 +
 arch/arm/Kconfig                      |    2 +
 arch/arm/include/asm/dma-contiguous.h |   15 ++
 arch/arm/include/asm/mach/map.h       |    1 +
 arch/arm/kernel/setup.c               |    9 +-
 arch/arm/mm/dma-mapping.c             |  369 ++++++++++++++++++++++++------
 arch/arm/mm/init.c                    |   23 ++-
 arch/arm/mm/mm.h                      |    3 +
 arch/arm/mm/mmu.c                     |   31 ++-
 arch/arm/plat-s5p/dev-mfc.c           |   51 +----
 arch/x86/Kconfig                      |    1 +
 arch/x86/include/asm/dma-contiguous.h |   13 +
 arch/x86/include/asm/dma-mapping.h    |    4 +
 arch/x86/kernel/pci-dma.c             |   18 ++-
 arch/x86/kernel/pci-nommu.c           |    8 +-
 arch/x86/kernel/setup.c               |    2 +
 drivers/base/Kconfig                  |   89 +++++++
 drivers/base/Makefile                 |    1 +
 drivers/base/dma-contiguous.c         |  401 +++++++++++++++++++++++++++++++
 include/asm-generic/dma-contiguous.h  |   28 +++
 include/linux/device.h                |    4 +
 include/linux/dma-contiguous.h        |  110 +++++++++
 include/linux/gfp.h                   |   12 +
 include/linux/mmzone.h                |   47 +++-
 include/linux/page-isolation.h        |   18 +-
 mm/Kconfig                            |    2 +-
 mm/Makefile                           |    3 +-
 mm/compaction.c                       |  418 +++++++++++++++++++++------------
 mm/internal.h                         |   33 +++
 mm/memory-failure.c                   |    2 +-
 mm/memory_hotplug.c                   |    6 +-
 mm/page_alloc.c                       |  409 ++++++++++++++++++++++++++++----
 mm/page_isolation.c                   |   15 +-
 mm/vmstat.c                           |    3 +
 35 files changed, 1790 insertions(+), 373 deletions(-)
 create mode 100644 arch/arm/include/asm/dma-contiguous.h
 create mode 100644 arch/x86/include/asm/dma-contiguous.h
 create mode 100644 drivers/base/dma-contiguous.c
 create mode 100644 include/asm-generic/dma-contiguous.h
 create mode 100644 include/linux/dma-contiguous.h

-- 
1.7.1.569.g6f426

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[PATCHv23 01/16] mm: page_alloc: remove trailing whitespace

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
---
 mm/page_alloc.c |   14 +++++++-------
 1 files changed, 7 insertions(+), 7 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 896cd4f..ba50b48 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -526,10 +526,10 @@ static inline int page_is_buddy(struct page *page, struct page *buddy,
  * free pages of length of (1 << order) and marked with _mapcount -2. Page's
  * order is recorded in page_private(page) field.
  * So when we are allocating or freeing one, we can derive the state of the
- * other.  That is, if we allocate a small block, and both were   
- * free, the remainder of the region must be split into blocks.   
+ * other.  That is, if we allocate a small block, and both were
+ * free, the remainder of the region must be split into blocks.
  * If a block is freed, and its buddy is also free, then this
- * triggers coalescing into a block of larger size.            
+ * triggers coalescing into a block of larger size.
  *
  * -- wli
  */
@@ -1074,17 +1074,17 @@ retry_reserve:
 	return page;
 }
 
-/* 
+/*
  * Obtain a specified number of elements from the buddy allocator, all under
  * a single hold of the lock, for efficiency.  Add them to the supplied list.
  * Returns the number of new pages which were placed at *list.
  */
-static int rmqueue_bulk(struct zone *zone, unsigned int order, 
+static int rmqueue_bulk(struct zone *zone, unsigned int order,
 			unsigned long count, struct list_head *list,
 			int migratetype, int cold)
 {
 	int i;
-	
+
 	spin_lock(&zone->lock);
 	for (i = 0; i < count; ++i) {
 		struct page *page = __rmqueue(zone, order, migratetype);
@@ -4309,7 +4309,7 @@ static void __paginginit free_area_init_core(struct pglist_data *pgdat,
 	init_waitqueue_head(&pgdat->kswapd_wait);
 	pgdat->kswapd_max_order = 0;
 	pgdat_page_cgroup_init(pgdat);
-	
+
 	for (j = 0; j < MAX_NR_ZONES; j++) {
 		struct zone *zone = pgdat->node_zones + j;
 		unsigned long size, realsize, memmap_pages;
-- 
1.7.1.569.g6f426

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[PATCHv23 02/16] mm: compaction: introduce isolate_migratepages_range()

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit introduces isolate_migratepages_range() function which
extracts functionality from isolate_migratepages() so that it can be
used on arbitrary PFN ranges.

isolate_migratepages() function is implemented as a simple wrapper
around isolate_migratepages_range().

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 mm/compaction.c |   75 +++++++++++++++++++++++++++++++++++++++---------------
 1 files changed, 54 insertions(+), 21 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index 74a8c82..ee20fc0 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -250,31 +250,34 @@ typedef enum {
 	ISOLATE_SUCCESS,	/* Pages isolated, migrate */
 } isolate_migrate_t;
 
-/*
- * Isolate all pages that can be migrated from the block pointed to by
- * the migrate scanner within compact_control.
+/**
+ * isolate_migratepages_range() - isolate all migrate-able pages in range.
+ * @zone:	Zone pages are in.
+ * @cc:		Compaction control structure.
+ * @low_pfn:	The first PFN of the range.
+ * @end_pfn:	The one-past-the-last PFN of the range.
+ *
+ * Isolate all pages that can be migrated from the range specified by
+ * [low_pfn, end_pfn).  Returns zero if there is a fatal signal
+ * pending), otherwise PFN of the first page that was not scanned
+ * (which may be both less, equal to or more then end_pfn).
+ *
+ * Assumes that cc->migratepages is empty and cc->nr_migratepages is
+ * zero.
+ *
+ * Apart from cc->migratepages and cc->nr_migratetypes this function
+ * does not modify any cc's fields, in particular it does not modify
+ * (or read for that matter) cc->migrate_pfn.
  */
-static isolate_migrate_t isolate_migratepages(struct zone *zone,
-					struct compact_control *cc)
+static unsigned long
+isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
+			   unsigned long low_pfn, unsigned long end_pfn)
 {
-	unsigned long low_pfn, end_pfn;
 	unsigned long last_pageblock_nr = 0, pageblock_nr;
 	unsigned long nr_scanned = 0, nr_isolated = 0;
 	struct list_head *migratelist = &cc->migratepages;
 	isolate_mode_t mode = ISOLATE_ACTIVE|ISOLATE_INACTIVE;
 
-	/* Do not scan outside zone boundaries */
-	low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
-
-	/* Only scan within a pageblock boundary */
-	end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
-
-	/* Do not cross the free scanner or scan within a memory hole */
-	if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
-		cc->migrate_pfn = end_pfn;
-		return ISOLATE_NONE;
-	}
-
 	/*
 	 * Ensure that there are not too many pages isolated from the LRU
 	 * list by either parallel reclaimers or compaction. If there are,
@@ -283,12 +286,12 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 	while (unlikely(too_many_isolated(zone))) {
 		/* async migration should just abort */
 		if (!cc->sync)
-			return ISOLATE_ABORT;
+			return 0;
 
 		congestion_wait(BLK_RW_ASYNC, HZ/10);
 
 		if (fatal_signal_pending(current))
-			return ISOLATE_ABORT;
+			return 0;
 	}
 
 	/* Time to isolate some pages for migration */
@@ -396,10 +399,40 @@ static isolate_migrate_t isolate_migratepages(struct zone *zone,
 	acct_isolated(zone, cc);
 
 	spin_unlock_irq(&zone->lru_lock);
-	cc->migrate_pfn = low_pfn;
 
 	trace_mm_compaction_isolate_migratepages(nr_scanned, nr_isolated);
 
+	return low_pfn;
+}
+
+/*
+ * Isolate all pages that can be migrated from the block pointed to by
+ * the migrate scanner within compact_control.
+ */
+static isolate_migrate_t isolate_migratepages(struct zone *zone,
+					struct compact_control *cc)
+{
+	unsigned long low_pfn, end_pfn;
+
+	/* Do not scan outside zone boundaries */
+	low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
+
+	/* Only scan within a pageblock boundary */
+	end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
+
+	/* Do not cross the free scanner or scan within a memory hole */
+	if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
+		cc->migrate_pfn = end_pfn;
+		return ISOLATE_NONE;
+	}
+
+	/* Perform the isolation */
+	low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
+	if (!low_pfn)
+		return ISOLATE_ABORT;
+
+	cc->migrate_pfn = low_pfn;
+
 	return ISOLATE_SUCCESS;
 }
 
-- 
1.7.1.569.g6f426

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[PATCHv23 03/16] mm: compaction: introduce map_pages()

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit creates a map_pages() function which map pages freed
using split_free_pages().  This merely moves some code from
isolate_freepages() so that it can be reused in other places.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 mm/compaction.c |   15 +++++++++++----
 1 files changed, 11 insertions(+), 4 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index ee20fc0..d9d7b35 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -127,6 +127,16 @@ static bool suitable_migration_target(struct page *page)
 	return false;
 }
 
+static void map_pages(struct list_head *list)
+{
+	struct page *page;
+
+	list_for_each_entry(page, list, lru) {
+		arch_alloc_page(page, 0);
+		kernel_map_pages(page, 1, 1);
+	}
+}
+
 /*
  * Based on information in the current compact_control, find blocks
  * suitable for isolating free pages from and then isolate them.
@@ -206,10 +216,7 @@ static void isolate_freepages(struct zone *zone,
 	}
 
 	/* split_free_page does not map the pages */
-	list_for_each_entry(page, freelist, lru) {
-		arch_alloc_page(page, 0);
-		kernel_map_pages(page, 1, 1);
-	}
+	map_pages(freelist);
 
 	cc->free_pfn = high_pfn;
 	cc->nr_freepages = nr_freepages;
-- 
1.7.1.569.g6f426

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[PATCHv23 04/16] mm: compaction: introduce isolate_freepages_range()

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit introduces isolate_freepages_range() function which
generalises isolate_freepages_block() so that it can be used on
arbitrary PFN ranges.

isolate_freepages_block() is left with only minor changes.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 mm/compaction.c |  111 ++++++++++++++++++++++++++++++++++++++++++++++---------
 1 files changed, 93 insertions(+), 18 deletions(-)

diff --git a/mm/compaction.c b/mm/compaction.c
index d9d7b35..06b198f 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -54,24 +54,20 @@ static unsigned long release_freepages(struct list_head *freelist)
 	return count;
 }
 
-/* Isolate free pages onto a private freelist. Must hold zone->lock */
-static unsigned long isolate_freepages_block(struct zone *zone,
-				unsigned long blockpfn,
-				struct list_head *freelist)
+/*
+ * Isolate free pages onto a private freelist. Caller must hold zone->lock.
+ * If @strict is true, will abort returning 0 on any invalid PFNs or non-free
+ * pages inside of the pageblock (even though it may still end up isolating
+ * some pages).
+ */
+static unsigned long isolate_freepages_block(unsigned long blockpfn,
+				unsigned long end_pfn,
+				struct list_head *freelist,
+				bool strict)
 {
-	unsigned long zone_end_pfn, end_pfn;
 	int nr_scanned = 0, total_isolated = 0;
 	struct page *cursor;
 
-	/* Get the last PFN we should scan for free pages at */
-	zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
-	end_pfn = min(blockpfn + pageblock_nr_pages, zone_end_pfn);
-
-	/* Find the first usable PFN in the block to initialse page cursor */
-	for (; blockpfn < end_pfn; blockpfn++) {
-		if (pfn_valid_within(blockpfn))
-			break;
-	}
 	cursor = pfn_to_page(blockpfn);
 
 	/* Isolate free pages. This assumes the block is valid */
@@ -79,15 +75,23 @@ static unsigned long isolate_freepages_block(struct zone *zone,
 		int isolated, i;
 		struct page *page = cursor;
 
-		if (!pfn_valid_within(blockpfn))
+		if (!pfn_valid_within(blockpfn)) {
+			if (strict)
+				return 0;
 			continue;
+		}
 		nr_scanned++;
 
-		if (!PageBuddy(page))
+		if (!PageBuddy(page)) {
+			if (strict)
+				return 0;
 			continue;
+		}
 
 		/* Found a free page, break it into order-0 pages */
 		isolated = split_free_page(page);
+		if (!isolated && strict)
+			return 0;
 		total_isolated += isolated;
 		for (i = 0; i < isolated; i++) {
 			list_add(&page->lru, freelist);
@@ -105,6 +109,73 @@ static unsigned long isolate_freepages_block(struct zone *zone,
 	return total_isolated;
 }
 
+/**
+ * isolate_freepages_range() - isolate free pages.
+ * @start_pfn: The first PFN to start isolating.
+ * @end_pfn:   The one-past-last PFN.
+ *
+ * Non-free pages, invalid PFNs, or zone boundaries within the
+ * [start_pfn, end_pfn) range are considered errors, cause function to
+ * undo its actions and return zero.
+ *
+ * Otherwise, function returns one-past-the-last PFN of isolated page
+ * (which may be greater then end_pfn if end fell in a middle of
+ * a free page).
+ */
+static unsigned long
+isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn)
+{
+	unsigned long isolated, pfn, block_end_pfn, flags;
+	struct zone *zone = NULL;
+	LIST_HEAD(freelist);
+
+	if (pfn_valid(start_pfn))
+		zone = page_zone(pfn_to_page(start_pfn));
+
+	for (pfn = start_pfn; pfn < end_pfn; pfn += isolated) {
+		if (!pfn_valid(pfn) || zone != page_zone(pfn_to_page(pfn)))
+			break;
+
+		/*
+		 * On subsequent iterations ALIGN() is actually not needed,
+		 * but we keep it that we not to complicate the code.
+		 */
+		block_end_pfn = ALIGN(pfn + 1, pageblock_nr_pages);
+		block_end_pfn = min(block_end_pfn, end_pfn);
+
+		spin_lock_irqsave(&zone->lock, flags);
+		isolated = isolate_freepages_block(pfn, block_end_pfn,
+						   &freelist, true);
+		spin_unlock_irqrestore(&zone->lock, flags);
+
+		/*
+		 * In strict mode, isolate_freepages_block() returns 0 if
+		 * there are any holes in the block (ie. invalid PFNs or
+		 * non-free pages).
+		 */
+		if (!isolated)
+			break;
+
+		/*
+		 * If we managed to isolate pages, it is always (1 << n) *
+		 * pageblock_nr_pages for some non-negative n.  (Max order
+		 * page may span two pageblocks).
+		 */
+	}
+
+	/* split_free_page does not map the pages */
+	map_pages(&freelist);
+
+	if (pfn < end_pfn) {
+		/* Loop terminated early, cleanup. */
+		release_freepages(&freelist);
+		return 0;
+	}
+
+	/* We don't use freelists for anything. */
+	return pfn;
+}
+
 /* Returns true if the page is within a block suitable for migration to */
 static bool suitable_migration_target(struct page *page)
 {
@@ -145,7 +216,7 @@ static void isolate_freepages(struct zone *zone,
 				struct compact_control *cc)
 {
 	struct page *page;
-	unsigned long high_pfn, low_pfn, pfn;
+	unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn;
 	unsigned long flags;
 	int nr_freepages = cc->nr_freepages;
 	struct list_head *freelist = &cc->freepages;
@@ -165,6 +236,8 @@ static void isolate_freepages(struct zone *zone,
 	 */
 	high_pfn = min(low_pfn, pfn);
 
+	zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
+
 	/*
 	 * Isolate free pages until enough are available to migrate the
 	 * pages on cc->migratepages. We stop searching if the migrate
@@ -201,7 +274,9 @@ static void isolate_freepages(struct zone *zone,
 		isolated = 0;
 		spin_lock_irqsave(&zone->lock, flags);
 		if (suitable_migration_target(page)) {
-			isolated = isolate_freepages_block(zone, pfn, freelist);
+			end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
+			isolated = isolate_freepages_block(pfn, end_pfn,
+							   freelist, false);
 			nr_freepages += isolated;
 		}
 		spin_unlock_irqrestore(&zone->lock, flags);
-- 
1.7.1.569.g6f426

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[PATCHv23 05/16] mm: compaction: export some of the functions

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit exports some of the functions from compaction.c file
outside of it adding their declaration into internal.h header
file so that other mm related code can use them.

This forced compaction.c to always be compiled (as opposed to being
compiled only if CONFIG_COMPACTION is defined) but as to avoid
introducing code that user did not ask for, part of the compaction.c
is now wrapped in on #ifdef.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 mm/Makefile     |    3 +-
 mm/compaction.c |  328 ++++++++++++++++++++++++++-----------------------------
 mm/internal.h   |   33 ++++++
 3 files changed, 191 insertions(+), 173 deletions(-)

diff --git a/mm/Makefile b/mm/Makefile
index 306742a..309424c 100644
--- a/mm/Makefile
+++ b/mm/Makefile
@@ -13,7 +13,7 @@ obj-y			:= filemap.o mempool.o oom_kill.o fadvise.o \
 			   readahead.o swap.o truncate.o vmscan.o shmem.o \
 			   prio_tree.o util.o mmzone.o vmstat.o backing-dev.o \
 			   page_isolation.o mm_init.o mmu_context.o percpu.o \
-			   $(mmu-y)
+			   compaction.o $(mmu-y)
 obj-y += init-mm.o
 
 ifdef CONFIG_NO_BOOTMEM
@@ -33,7 +33,6 @@ obj-$(CONFIG_NUMA) 	+= mempolicy.o
 obj-$(CONFIG_SPARSEMEM)	+= sparse.o
 obj-$(CONFIG_SPARSEMEM_VMEMMAP) += sparse-vmemmap.o
 obj-$(CONFIG_SLOB) += slob.o
-obj-$(CONFIG_COMPACTION) += compaction.o
 obj-$(CONFIG_MMU_NOTIFIER) += mmu_notifier.o
 obj-$(CONFIG_KSM) += ksm.o
 obj-$(CONFIG_PAGE_POISONING) += debug-pagealloc.o
diff --git a/mm/compaction.c b/mm/compaction.c
index 06b198f..7a92e41 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -16,30 +16,11 @@
 #include <linux/sysfs.h>
 #include "internal.h"
 
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+
 #define CREATE_TRACE_POINTS
 #include <trace/events/compaction.h>
 
-/*
- * compact_control is used to track pages being migrated and the free pages
- * they are being migrated to during memory compaction. The free_pfn starts
- * at the end of a zone and migrate_pfn begins at the start. Movable pages
- * are moved to the end of a zone during a compaction run and the run
- * completes when free_pfn <= migrate_pfn
- */
-struct compact_control {
-	struct list_head freepages;	/* List of free pages to migrate to */
-	struct list_head migratepages;	/* List of pages being migrated */
-	unsigned long nr_freepages;	/* Number of isolated free pages */
-	unsigned long nr_migratepages;	/* Number of pages to migrate */
-	unsigned long free_pfn;		/* isolate_freepages search base */
-	unsigned long migrate_pfn;	/* isolate_migratepages search base */
-	bool sync;			/* Synchronous migration */
-
-	int order;			/* order a direct compactor needs */
-	int migratetype;		/* MOVABLE, RECLAIMABLE etc */
-	struct zone *zone;
-};
-
 static unsigned long release_freepages(struct list_head *freelist)
 {
 	struct page *page, *next;
@@ -54,6 +35,16 @@ static unsigned long release_freepages(struct list_head *freelist)
 	return count;
 }
 
+static void map_pages(struct list_head *list)
+{
+	struct page *page;
+
+	list_for_each_entry(page, list, lru) {
+		arch_alloc_page(page, 0);
+		kernel_map_pages(page, 1, 1);
+	}
+}
+
 /*
  * Isolate free pages onto a private freelist. Caller must hold zone->lock.
  * If @strict is true, will abort returning 0 on any invalid PFNs or non-free
@@ -122,7 +113,7 @@ static unsigned long isolate_freepages_block(unsigned long blockpfn,
  * (which may be greater then end_pfn if end fell in a middle of
  * a free page).
  */
-static unsigned long
+unsigned long
 isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn)
 {
 	unsigned long isolated, pfn, block_end_pfn, flags;
@@ -176,127 +167,6 @@ isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn)
 	return pfn;
 }
 
-/* Returns true if the page is within a block suitable for migration to */
-static bool suitable_migration_target(struct page *page)
-{
-
-	int migratetype = get_pageblock_migratetype(page);
-
-	/* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
-	if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
-		return false;
-
-	/* If the page is a large free page, then allow migration */
-	if (PageBuddy(page) && page_order(page) >= pageblock_order)
-		return true;
-
-	/* If the block is MIGRATE_MOVABLE, allow migration */
-	if (migratetype == MIGRATE_MOVABLE)
-		return true;
-
-	/* Otherwise skip the block */
-	return false;
-}
-
-static void map_pages(struct list_head *list)
-{
-	struct page *page;
-
-	list_for_each_entry(page, list, lru) {
-		arch_alloc_page(page, 0);
-		kernel_map_pages(page, 1, 1);
-	}
-}
-
-/*
- * Based on information in the current compact_control, find blocks
- * suitable for isolating free pages from and then isolate them.
- */
-static void isolate_freepages(struct zone *zone,
-				struct compact_control *cc)
-{
-	struct page *page;
-	unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn;
-	unsigned long flags;
-	int nr_freepages = cc->nr_freepages;
-	struct list_head *freelist = &cc->freepages;
-
-	/*
-	 * Initialise the free scanner. The starting point is where we last
-	 * scanned from (or the end of the zone if starting). The low point
-	 * is the end of the pageblock the migration scanner is using.
-	 */
-	pfn = cc->free_pfn;
-	low_pfn = cc->migrate_pfn + pageblock_nr_pages;
-
-	/*
-	 * Take care that if the migration scanner is at the end of the zone
-	 * that the free scanner does not accidentally move to the next zone
-	 * in the next isolation cycle.
-	 */
-	high_pfn = min(low_pfn, pfn);
-
-	zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
-
-	/*
-	 * Isolate free pages until enough are available to migrate the
-	 * pages on cc->migratepages. We stop searching if the migrate
-	 * and free page scanners meet or enough free pages are isolated.
-	 */
-	for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
-					pfn -= pageblock_nr_pages) {
-		unsigned long isolated;
-
-		if (!pfn_valid(pfn))
-			continue;
-
-		/*
-		 * Check for overlapping nodes/zones. It's possible on some
-		 * configurations to have a setup like
-		 * node0 node1 node0
-		 * i.e. it's possible that all pages within a zones range of
-		 * pages do not belong to a single zone.
-		 */
-		page = pfn_to_page(pfn);
-		if (page_zone(page) != zone)
-			continue;
-
-		/* Check the block is suitable for migration */
-		if (!suitable_migration_target(page))
-			continue;
-
-		/*
-		 * Found a block suitable for isolating free pages from. Now
-		 * we disabled interrupts, double check things are ok and
-		 * isolate the pages. This is to minimise the time IRQs
-		 * are disabled
-		 */
-		isolated = 0;
-		spin_lock_irqsave(&zone->lock, flags);
-		if (suitable_migration_target(page)) {
-			end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
-			isolated = isolate_freepages_block(pfn, end_pfn,
-							   freelist, false);
-			nr_freepages += isolated;
-		}
-		spin_unlock_irqrestore(&zone->lock, flags);
-
-		/*
-		 * Record the highest PFN we isolated pages from. When next
-		 * looking for free pages, the search will restart here as
-		 * page migration may have returned some pages to the allocator
-		 */
-		if (isolated)
-			high_pfn = max(high_pfn, pfn);
-	}
-
-	/* split_free_page does not map the pages */
-	map_pages(freelist);
-
-	cc->free_pfn = high_pfn;
-	cc->nr_freepages = nr_freepages;
-}
-
 /* Update the number of anon and file isolated pages in the zone */
 static void acct_isolated(struct zone *zone, struct compact_control *cc)
 {
@@ -325,13 +195,6 @@ static bool too_many_isolated(struct zone *zone)
 	return isolated > (inactive + active) / 2;
 }
 
-/* possible outcome of isolate_migratepages */
-typedef enum {
-	ISOLATE_ABORT,		/* Abort compaction now */
-	ISOLATE_NONE,		/* No pages isolated, continue scanning */
-	ISOLATE_SUCCESS,	/* Pages isolated, migrate */
-} isolate_migrate_t;
-
 /**
  * isolate_migratepages_range() - isolate all migrate-able pages in range.
  * @zone:	Zone pages are in.
@@ -351,7 +214,7 @@ typedef enum {
  * does not modify any cc's fields, in particular it does not modify
  * (or read for that matter) cc->migrate_pfn.
  */
-static unsigned long
+unsigned long
 isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 			   unsigned long low_pfn, unsigned long end_pfn)
 {
@@ -487,35 +350,118 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 	return low_pfn;
 }
 
+#endif /* CONFIG_COMPACTION || CONFIG_CMA */
+#ifdef CONFIG_COMPACTION
+
+/* Returns true if the page is within a block suitable for migration to */
+static bool suitable_migration_target(struct page *page)
+{
+
+	int migratetype = get_pageblock_migratetype(page);
+
+	/* Don't interfere with memory hot-remove or the min_free_kbytes blocks */
+	if (migratetype == MIGRATE_ISOLATE || migratetype == MIGRATE_RESERVE)
+		return false;
+
+	/* If the page is a large free page, then allow migration */
+	if (PageBuddy(page) && page_order(page) >= pageblock_order)
+		return true;
+
+	/* If the block is MIGRATE_MOVABLE, allow migration */
+	if (migratetype == MIGRATE_MOVABLE)
+		return true;
+
+	/* Otherwise skip the block */
+	return false;
+}
+
 /*
- * Isolate all pages that can be migrated from the block pointed to by
- * the migrate scanner within compact_control.
+ * Based on information in the current compact_control, find blocks
+ * suitable for isolating free pages from and then isolate them.
  */
-static isolate_migrate_t isolate_migratepages(struct zone *zone,
-					struct compact_control *cc)
+static void isolate_freepages(struct zone *zone,
+				struct compact_control *cc)
 {
-	unsigned long low_pfn, end_pfn;
+	struct page *page;
+	unsigned long high_pfn, low_pfn, pfn, zone_end_pfn, end_pfn;
+	unsigned long flags;
+	int nr_freepages = cc->nr_freepages;
+	struct list_head *freelist = &cc->freepages;
 
-	/* Do not scan outside zone boundaries */
-	low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
+	/*
+	 * Initialise the free scanner. The starting point is where we last
+	 * scanned from (or the end of the zone if starting). The low point
+	 * is the end of the pageblock the migration scanner is using.
+	 */
+	pfn = cc->free_pfn;
+	low_pfn = cc->migrate_pfn + pageblock_nr_pages;
 
-	/* Only scan within a pageblock boundary */
-	end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
+	/*
+	 * Take care that if the migration scanner is at the end of the zone
+	 * that the free scanner does not accidentally move to the next zone
+	 * in the next isolation cycle.
+	 */
+	high_pfn = min(low_pfn, pfn);
 
-	/* Do not cross the free scanner or scan within a memory hole */
-	if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
-		cc->migrate_pfn = end_pfn;
-		return ISOLATE_NONE;
-	}
+	zone_end_pfn = zone->zone_start_pfn + zone->spanned_pages;
 
-	/* Perform the isolation */
-	low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
-	if (!low_pfn)
-		return ISOLATE_ABORT;
+	/*
+	 * Isolate free pages until enough are available to migrate the
+	 * pages on cc->migratepages. We stop searching if the migrate
+	 * and free page scanners meet or enough free pages are isolated.
+	 */
+	for (; pfn > low_pfn && cc->nr_migratepages > nr_freepages;
+					pfn -= pageblock_nr_pages) {
+		unsigned long isolated;
 
-	cc->migrate_pfn = low_pfn;
+		if (!pfn_valid(pfn))
+			continue;
 
-	return ISOLATE_SUCCESS;
+		/*
+		 * Check for overlapping nodes/zones. It's possible on some
+		 * configurations to have a setup like
+		 * node0 node1 node0
+		 * i.e. it's possible that all pages within a zones range of
+		 * pages do not belong to a single zone.
+		 */
+		page = pfn_to_page(pfn);
+		if (page_zone(page) != zone)
+			continue;
+
+		/* Check the block is suitable for migration */
+		if (!suitable_migration_target(page))
+			continue;
+
+		/*
+		 * Found a block suitable for isolating free pages from. Now
+		 * we disabled interrupts, double check things are ok and
+		 * isolate the pages. This is to minimise the time IRQs
+		 * are disabled
+		 */
+		isolated = 0;
+		spin_lock_irqsave(&zone->lock, flags);
+		if (suitable_migration_target(page)) {
+			end_pfn = min(pfn + pageblock_nr_pages, zone_end_pfn);
+			isolated = isolate_freepages_block(pfn, end_pfn,
+							   freelist, false);
+			nr_freepages += isolated;
+		}
+		spin_unlock_irqrestore(&zone->lock, flags);
+
+		/*
+		 * Record the highest PFN we isolated pages from. When next
+		 * looking for free pages, the search will restart here as
+		 * page migration may have returned some pages to the allocator
+		 */
+		if (isolated)
+			high_pfn = max(high_pfn, pfn);
+	}
+
+	/* split_free_page does not map the pages */
+	map_pages(freelist);
+
+	cc->free_pfn = high_pfn;
+	cc->nr_freepages = nr_freepages;
 }
 
 /*
@@ -564,6 +510,44 @@ static void update_nr_listpages(struct compact_control *cc)
 	cc->nr_freepages = nr_freepages;
 }
 
+/* possible outcome of isolate_migratepages */
+typedef enum {
+	ISOLATE_ABORT,		/* Abort compaction now */
+	ISOLATE_NONE,		/* No pages isolated, continue scanning */
+	ISOLATE_SUCCESS,	/* Pages isolated, migrate */
+} isolate_migrate_t;
+
+/*
+ * Isolate all pages that can be migrated from the block pointed to by
+ * the migrate scanner within compact_control.
+ */
+static isolate_migrate_t isolate_migratepages(struct zone *zone,
+					struct compact_control *cc)
+{
+	unsigned long low_pfn, end_pfn;
+
+	/* Do not scan outside zone boundaries */
+	low_pfn = max(cc->migrate_pfn, zone->zone_start_pfn);
+
+	/* Only scan within a pageblock boundary */
+	end_pfn = ALIGN(low_pfn + pageblock_nr_pages, pageblock_nr_pages);
+
+	/* Do not cross the free scanner or scan within a memory hole */
+	if (end_pfn > cc->free_pfn || !pfn_valid(low_pfn)) {
+		cc->migrate_pfn = end_pfn;
+		return ISOLATE_NONE;
+	}
+
+	/* Perform the isolation */
+	low_pfn = isolate_migratepages_range(zone, cc, low_pfn, end_pfn);
+	if (!low_pfn)
+		return ISOLATE_ABORT;
+
+	cc->migrate_pfn = low_pfn;
+
+	return ISOLATE_SUCCESS;
+}
+
 static int compact_finished(struct zone *zone,
 			    struct compact_control *cc)
 {
@@ -910,3 +894,5 @@ void compaction_unregister_node(struct node *node)
 	return device_remove_file(&node->dev, &dev_attr_compact);
 }
 #endif /* CONFIG_SYSFS && CONFIG_NUMA */
+
+#endif /* CONFIG_COMPACTION */
diff --git a/mm/internal.h b/mm/internal.h
index 2189af4..aee4761 100644
--- a/mm/internal.h
+++ b/mm/internal.h
@@ -100,6 +100,39 @@ extern void prep_compound_page(struct page *page, unsigned long order);
 extern bool is_free_buddy_page(struct page *page);
 #endif
 
+#if defined CONFIG_COMPACTION || defined CONFIG_CMA
+
+/*
+ * in mm/compaction.c
+ */
+/*
+ * compact_control is used to track pages being migrated and the free pages
+ * they are being migrated to during memory compaction. The free_pfn starts
+ * at the end of a zone and migrate_pfn begins at the start. Movable pages
+ * are moved to the end of a zone during a compaction run and the run
+ * completes when free_pfn <= migrate_pfn
+ */
+struct compact_control {
+	struct list_head freepages;	/* List of free pages to migrate to */
+	struct list_head migratepages;	/* List of pages being migrated */
+	unsigned long nr_freepages;	/* Number of isolated free pages */
+	unsigned long nr_migratepages;	/* Number of pages to migrate */
+	unsigned long free_pfn;		/* isolate_freepages search base */
+	unsigned long migrate_pfn;	/* isolate_migratepages search base */
+	bool sync;			/* Synchronous migration */
+
+	int order;			/* order a direct compactor needs */
+	int migratetype;		/* MOVABLE, RECLAIMABLE etc */
+	struct zone *zone;
+};
+
+unsigned long
+isolate_freepages_range(unsigned long start_pfn, unsigned long end_pfn);
+unsigned long
+isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
+			   unsigned long low_pfn, unsigned long end_pfn);
+
+#endif
 
 /*
  * function for dealing with page's order in buddy system.
-- 
1.7.1.569.g6f426

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

[PATCHv23 06/16] mm: page_alloc: introduce alloc_contig_range()

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit adds the alloc_contig_range() function which tries
to allocate given range of pages.  It tries to migrate all
already allocated pages that fall in the range thus freeing them.
Once all pages in the range are freed they are removed from the
buddy system thus allocated for the caller to use.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 include/linux/gfp.h |    8 ++
 mm/page_alloc.c     |  185 +++++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 193 insertions(+), 0 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 581e74b..052a5b6 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -391,4 +391,12 @@ static inline bool pm_suspended_storage(void)
 }
 #endif /* CONFIG_PM_SLEEP */
 
+#ifdef CONFIG_CMA
+
+/* The below functions must be run on a range from a single zone. */
+extern int alloc_contig_range(unsigned long start, unsigned long end);
+extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
+
+#endif
+
 #endif /* __LINUX_GFP_H */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ba50b48..24094058 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -57,6 +57,7 @@
 #include <linux/ftrace_event.h>
 #include <linux/memcontrol.h>
 #include <linux/prefetch.h>
+#include <linux/migrate.h>
 #include <linux/page-debug-flags.h>
 
 #include <asm/tlbflush.h>
@@ -5563,6 +5564,190 @@ out:
 	spin_unlock_irqrestore(&zone->lock, flags);
 }
 
+#ifdef CONFIG_CMA
+
+static unsigned long pfn_align_to_maxpage_down(unsigned long pfn)
+{
+	return pfn & ~(MAX_ORDER_NR_PAGES - 1);
+}
+
+static unsigned long pfn_align_to_maxpage_up(unsigned long pfn)
+{
+	return ALIGN(pfn, MAX_ORDER_NR_PAGES);
+}
+
+static struct page *
+__alloc_contig_migrate_alloc(struct page *page, unsigned long private,
+			     int **resultp)
+{
+	return alloc_page(GFP_HIGHUSER_MOVABLE);
+}
+
+/* [start, end) must belong to a single zone. */
+static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
+{
+	/* This function is based on compact_zone() from compaction.c. */
+
+	unsigned long pfn = start;
+	unsigned int tries = 0;
+	int ret = 0;
+
+	struct compact_control cc = {
+		.nr_migratepages = 0,
+		.order = -1,
+		.zone = page_zone(pfn_to_page(start)),
+		.sync = true,
+	};
+	INIT_LIST_HEAD(&cc.migratepages);
+
+	migrate_prep_local();
+
+	while (pfn < end || !list_empty(&cc.migratepages)) {
+		if (fatal_signal_pending(current)) {
+			ret = -EINTR;
+			break;
+		}
+
+		if (list_empty(&cc.migratepages)) {
+			cc.nr_migratepages = 0;
+			pfn = isolate_migratepages_range(cc.zone, &cc,
+							 pfn, end);
+			if (!pfn) {
+				ret = -EINTR;
+				break;
+			}
+			tries = 0;
+		} else if (++tries == 5) {
+			ret = ret < 0 ? ret : -EBUSY;
+			break;
+		}
+
+		ret = migrate_pages(&cc.migratepages,
+				    __alloc_contig_migrate_alloc,
+				    0, false, true);
+	}
+
+	putback_lru_pages(&cc.migratepages);
+	return ret > 0 ? 0 : ret;
+}
+
+/**
+ * alloc_contig_range() -- tries to allocate given range of pages
+ * @start:	start PFN to allocate
+ * @end:	one-past-the-last PFN to allocate
+ *
+ * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
+ * aligned, however it's the caller's responsibility to guarantee that
+ * we are the only thread that changes migrate type of pageblocks the
+ * pages fall in.
+ *
+ * The PFN range must belong to a single zone.
+ *
+ * Returns zero on success or negative error code.  On success all
+ * pages which PFN is in [start, end) are allocated for the caller and
+ * need to be freed with free_contig_range().
+ */
+int alloc_contig_range(unsigned long start, unsigned long end)
+{
+	struct zone *zone = page_zone(pfn_to_page(start));
+	unsigned long outer_start, outer_end;
+	int ret = 0, order;
+
+	/*
+	 * What we do here is we mark all pageblocks in range as
+	 * MIGRATE_ISOLATE.  Because of the way page allocator work, we
+	 * align the range to MAX_ORDER pages so that page allocator
+	 * won't try to merge buddies from different pageblocks and
+	 * change MIGRATE_ISOLATE to some other migration type.
+	 *
+	 * Once the pageblocks are marked as MIGRATE_ISOLATE, we
+	 * migrate the pages from an unaligned range (ie. pages that
+	 * we are interested in).  This will put all the pages in
+	 * range back to page allocator as MIGRATE_ISOLATE.
+	 *
+	 * When this is done, we take the pages in range from page
+	 * allocator removing them from the buddy system.  This way
+	 * page allocator will never consider using them.
+	 *
+	 * This lets us mark the pageblocks back as
+	 * MIGRATE_CMA/MIGRATE_MOVABLE so that free pages in the
+	 * MAX_ORDER aligned range but not in the unaligned, original
+	 * range are put back to page allocator so that buddy can use
+	 * them.
+	 */
+
+	ret = start_isolate_page_range(pfn_align_to_maxpage_down(start),
+				       pfn_align_to_maxpage_up(end));
+	if (ret)
+		goto done;
+
+	ret = __alloc_contig_migrate_range(start, end);
+	if (ret)
+		goto done;
+
+	/*
+	 * Pages from [start, end) are within a MAX_ORDER_NR_PAGES
+	 * aligned blocks that are marked as MIGRATE_ISOLATE.  What's
+	 * more, all pages in [start, end) are free in page allocator.
+	 * What we are going to do is to allocate all pages from
+	 * [start, end) (that is remove them from page allocator).
+	 *
+	 * The only problem is that pages at the beginning and at the
+	 * end of interesting range may be not aligned with pages that
+	 * page allocator holds, ie. they can be part of higher order
+	 * pages.  Because of this, we reserve the bigger range and
+	 * once this is done free the pages we are not interested in.
+	 *
+	 * We don't have to hold zone->lock here because the pages are
+	 * isolated thus they won't get removed from buddy.
+	 */
+
+	lru_add_drain_all();
+	drain_all_pages();
+
+	order = 0;
+	outer_start = start;
+	while (!PageBuddy(pfn_to_page(outer_start))) {
+		if (++order >= MAX_ORDER) {
+			ret = -EBUSY;
+			goto done;
+		}
+		outer_start &= ~0UL << order;
+	}
+
+	/* Make sure the range is really isolated. */
+	if (test_pages_isolated(outer_start, end)) {
+		pr_warn("alloc_contig_range test_pages_isolated(%lx, %lx) failed\n",
+		       outer_start, end);
+		ret = -EBUSY;
+		goto done;
+	}
+
+	outer_end = isolate_freepages_range(outer_start, end);
+	if (!outer_end) {
+		ret = -EBUSY;
+		goto done;
+	}
+
+	/* Free head and tail (if any) */
+	if (start != outer_start)
+		free_contig_range(outer_start, start - outer_start);
+	if (end != outer_end)
+		free_contig_range(end, outer_end - end);
+
+done:
+	undo_isolate_page_range(pfn_align_to_maxpage_down(start),
+				pfn_align_to_maxpage_up(end));
+	return ret;
+}
+
+void free_contig_range(unsigned long pfn, unsigned nr_pages)
+{
+	for (; nr_pages--; ++pfn)
+		__free_page(pfn_to_page(pfn));
+}
+#endif
+
 #ifdef CONFIG_MEMORY_HOTREMOVE
 /*
  * All pages in the range must be isolated before calling this.
-- 
1.7.1.569.g6f426

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[PATCHv23 07/16] mm: page_alloc: change fallbacks array handling

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit adds a row for MIGRATE_ISOLATE type to the fallbacks array
which was missing from it.  It also, changes the array traversal logic
a little making MIGRATE_RESERVE an end marker.  The letter change,
removes the implicit MIGRATE_UNMOVABLE from the end of each row which
was read by __rmqueue_fallback() function.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 mm/page_alloc.c |    9 +++++----
 1 files changed, 5 insertions(+), 4 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 24094058..ad840a7 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -888,11 +888,12 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
  * This array describes the order lists are fallen back to when
  * the free lists for the desirable migrate type are depleted
  */
-static int fallbacks[MIGRATE_TYPES][MIGRATE_TYPES-1] = {
+static int fallbacks[MIGRATE_TYPES][3] = {
 	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
 	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
 	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
-	[MIGRATE_RESERVE]     = { MIGRATE_RESERVE,     MIGRATE_RESERVE,   MIGRATE_RESERVE }, /* Never used */
+	[MIGRATE_RESERVE]     = { MIGRATE_RESERVE }, /* Never used */
+	[MIGRATE_ISOLATE]     = { MIGRATE_RESERVE }, /* Never used */
 };
 
 /*
@@ -987,12 +988,12 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
 	/* Find the largest possible block of pages in the other list */
 	for (current_order = MAX_ORDER-1; current_order >= order;
 						--current_order) {
-		for (i = 0; i < MIGRATE_TYPES - 1; i++) {
+		for (i = 0;; i++) {
 			migratetype = fallbacks[start_migratetype][i];
 
 			/* MIGRATE_RESERVE handled later if necessary */
 			if (migratetype == MIGRATE_RESERVE)
-				continue;
+				break;
 
 			area = &(zone->free_area[current_order]);
 			if (list_empty(&area->free_list[migratetype]))
-- 
1.7.1.569.g6f426

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[PATCHv23 08/16] mm: mmzone: MIGRATE_CMA migration type added

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

The MIGRATE_CMA migration type has two main characteristics:
(i) only movable pages can be allocated from MIGRATE_CMA
pageblocks and (ii) page allocator will never change migration
type of MIGRATE_CMA pageblocks.

This guarantees (to some degree) that page in a MIGRATE_CMA page
block can always be migrated somewhere else (unless there's no
memory left in the system).

It is designed to be used for allocating big chunks (eg. 10MiB)
of physically contiguous memory.  Once driver requests
contiguous memory, pages from MIGRATE_CMA pageblocks may be
migrated away to create a contiguous block.

To minimise number of migrations, MIGRATE_CMA migration type
is the last type tried when page allocator falls back to other
migration types when requested.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 include/linux/gfp.h    |    3 ++
 include/linux/mmzone.h |   38 +++++++++++++++++++----
 mm/Kconfig             |    2 +-
 mm/compaction.c        |   11 +++++--
 mm/page_alloc.c        |   76 +++++++++++++++++++++++++++++++++++++----------
 mm/vmstat.c            |    3 ++
 6 files changed, 106 insertions(+), 27 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 052a5b6..78d32a7 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -397,6 +397,9 @@ static inline bool pm_suspended_storage(void)
 extern int alloc_contig_range(unsigned long start, unsigned long end);
 extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
 
+/* CMA stuff */
+extern void init_cma_reserved_pageblock(struct page *page);
+
 #endif
 
 #endif /* __LINUX_GFP_H */
diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index f10a54c..4781f30 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -35,13 +35,37 @@
  */
 #define PAGE_ALLOC_COSTLY_ORDER 3
 
-#define MIGRATE_UNMOVABLE     0
-#define MIGRATE_RECLAIMABLE   1
-#define MIGRATE_MOVABLE       2
-#define MIGRATE_PCPTYPES      3 /* the number of types on the pcp lists */
-#define MIGRATE_RESERVE       3
-#define MIGRATE_ISOLATE       4 /* can't allocate from here */
-#define MIGRATE_TYPES         5
+enum {
+	MIGRATE_UNMOVABLE,
+	MIGRATE_RECLAIMABLE,
+	MIGRATE_MOVABLE,
+	MIGRATE_PCPTYPES,	/* the number of types on the pcp lists */
+	MIGRATE_RESERVE = MIGRATE_PCPTYPES,
+#ifdef CONFIG_CMA
+	/*
+	 * MIGRATE_CMA migration type is designed to mimic the way
+	 * ZONE_MOVABLE works.  Only movable pages can be allocated
+	 * from MIGRATE_CMA pageblocks and page allocator never
+	 * implicitly change migration type of MIGRATE_CMA pageblock.
+	 *
+	 * The way to use it is to change migratetype of a range of
+	 * pageblocks to MIGRATE_CMA which can be done by
+	 * __free_pageblock_cma() function.  What is important though
+	 * is that a range of pageblocks must be aligned to
+	 * MAX_ORDER_NR_PAGES should biggest page be bigger then
+	 * a single pageblock.
+	 */
+	MIGRATE_CMA,
+#endif
+	MIGRATE_ISOLATE,	/* can't allocate from here */
+	MIGRATE_TYPES
+};
+
+#ifdef CONFIG_CMA
+#  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
+#else
+#  define is_migrate_cma(migratetype) false
+#endif
 
 #define for_each_migratetype_order(order, type) \
 	for (order = 0; order < MAX_ORDER; order++) \
diff --git a/mm/Kconfig b/mm/Kconfig
index 2613c91..97ea5cd 100644
--- a/mm/Kconfig
+++ b/mm/Kconfig
@@ -198,7 +198,7 @@ config COMPACTION
 config MIGRATION
 	bool "Page migration"
 	def_bool y
-	depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION
+	depends on NUMA || ARCH_ENABLE_MEMORY_HOTREMOVE || COMPACTION || CMA
 	help
 	  Allows the migration of the physical location of pages of processes
 	  while the virtual addresses are not changed. This is useful in
diff --git a/mm/compaction.c b/mm/compaction.c
index 7a92e41..da7d35e 100644
--- a/mm/compaction.c
+++ b/mm/compaction.c
@@ -45,6 +45,11 @@ static void map_pages(struct list_head *list)
 	}
 }
 
+static inline bool migrate_async_suitable(int migratetype)
+{
+	return is_migrate_cma(migratetype) || migratetype == MIGRATE_MOVABLE;
+}
+
 /*
  * Isolate free pages onto a private freelist. Caller must hold zone->lock.
  * If @strict is true, will abort returning 0 on any invalid PFNs or non-free
@@ -299,7 +304,7 @@ isolate_migratepages_range(struct zone *zone, struct compact_control *cc,
 		 */
 		pageblock_nr = low_pfn >> pageblock_order;
 		if (!cc->sync && last_pageblock_nr != pageblock_nr &&
-				get_pageblock_migratetype(page) != MIGRATE_MOVABLE) {
+		    !migrate_async_suitable(get_pageblock_migratetype(page))) {
 			low_pfn += pageblock_nr_pages;
 			low_pfn = ALIGN(low_pfn, pageblock_nr_pages) - 1;
 			last_pageblock_nr = pageblock_nr;
@@ -367,8 +372,8 @@ static bool suitable_migration_target(struct page *page)
 	if (PageBuddy(page) && page_order(page) >= pageblock_order)
 		return true;
 
-	/* If the block is MIGRATE_MOVABLE, allow migration */
-	if (migratetype == MIGRATE_MOVABLE)
+	/* If the block is MIGRATE_MOVABLE or MIGRATE_CMA, allow migration */
+	if (migrate_async_suitable(migratetype))
 		return true;
 
 	/* Otherwise skip the block */
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index ad840a7..07bddbe 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -763,6 +763,24 @@ void __meminit __free_pages_bootmem(struct page *page, unsigned int order)
 	__free_pages(page, order);
 }
 
+#ifdef CONFIG_CMA
+/* Free whole pageblock and set it's migration type to MIGRATE_CMA. */
+void __init init_cma_reserved_pageblock(struct page *page)
+{
+	unsigned i = pageblock_nr_pages;
+	struct page *p = page;
+
+	do {
+		__ClearPageReserved(p);
+		set_page_count(p, 0);
+	} while (++p, --i);
+
+	set_page_refcounted(page);
+	set_pageblock_migratetype(page, MIGRATE_CMA);
+	__free_pages(page, pageblock_order);
+	totalram_pages += pageblock_nr_pages;
+}
+#endif
 
 /*
  * The order of subdivision here is critical for the IO subsystem.
@@ -888,10 +906,15 @@ struct page *__rmqueue_smallest(struct zone *zone, unsigned int order,
  * This array describes the order lists are fallen back to when
  * the free lists for the desirable migrate type are depleted
  */
-static int fallbacks[MIGRATE_TYPES][3] = {
-	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,   MIGRATE_RESERVE },
-	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,   MIGRATE_RESERVE },
-	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
+static int fallbacks[MIGRATE_TYPES][4] = {
+	[MIGRATE_UNMOVABLE]   = { MIGRATE_RECLAIMABLE, MIGRATE_MOVABLE,     MIGRATE_RESERVE },
+	[MIGRATE_RECLAIMABLE] = { MIGRATE_UNMOVABLE,   MIGRATE_MOVABLE,     MIGRATE_RESERVE },
+#ifdef CONFIG_CMA
+	[MIGRATE_MOVABLE]     = { MIGRATE_CMA,         MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE, MIGRATE_RESERVE },
+	[MIGRATE_CMA]         = { MIGRATE_RESERVE }, /* Never used */
+#else
+	[MIGRATE_MOVABLE]     = { MIGRATE_RECLAIMABLE, MIGRATE_UNMOVABLE,   MIGRATE_RESERVE },
+#endif
 	[MIGRATE_RESERVE]     = { MIGRATE_RESERVE }, /* Never used */
 	[MIGRATE_ISOLATE]     = { MIGRATE_RESERVE }, /* Never used */
 };
@@ -1008,11 +1031,18 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
 			 * pages to the preferred allocation list. If falling
 			 * back for a reclaimable kernel allocation, be more
 			 * aggressive about taking ownership of free pages
+			 *
+			 * On the other hand, never change migration
+			 * type of MIGRATE_CMA pageblocks nor move CMA
+			 * pages on different free lists. We don't
+			 * want unmovable pages to be allocated from
+			 * MIGRATE_CMA areas.
 			 */
-			if (unlikely(current_order >= (pageblock_order >> 1)) ||
-					start_migratetype == MIGRATE_RECLAIMABLE ||
-					page_group_by_mobility_disabled) {
-				unsigned long pages;
+			if (!is_migrate_cma(migratetype) &&
+			    (unlikely(current_order >= pageblock_order / 2) ||
+			     start_migratetype == MIGRATE_RECLAIMABLE ||
+			     page_group_by_mobility_disabled)) {
+				int pages;
 				pages = move_freepages_block(zone, page,
 								start_migratetype);
 
@@ -1030,11 +1060,14 @@ __rmqueue_fallback(struct zone *zone, int order, int start_migratetype)
 			rmv_page_order(page);
 
 			/* Take ownership for orders >= pageblock_order */
-			if (current_order >= pageblock_order)
+			if (current_order >= pageblock_order &&
+			    !is_migrate_cma(migratetype))
 				change_pageblock_range(page, current_order,
 							start_migratetype);
 
-			expand(zone, page, order, current_order, area, migratetype);
+			expand(zone, page, order, current_order, area,
+			       is_migrate_cma(migratetype)
+			     ? migratetype : start_migratetype);
 
 			trace_mm_page_alloc_extfrag(page, order, current_order,
 				start_migratetype, migratetype);
@@ -1085,7 +1118,7 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
 			unsigned long count, struct list_head *list,
 			int migratetype, int cold)
 {
-	int i;
+	int mt = migratetype, i;
 
 	spin_lock(&zone->lock);
 	for (i = 0; i < count; ++i) {
@@ -1106,7 +1139,12 @@ static int rmqueue_bulk(struct zone *zone, unsigned int order,
 			list_add(&page->lru, list);
 		else
 			list_add_tail(&page->lru, list);
-		set_page_private(page, migratetype);
+		if (IS_ENABLED(CONFIG_CMA)) {
+			mt = get_pageblock_migratetype(page);
+			if (!is_migrate_cma(mt) && mt != MIGRATE_ISOLATE)
+				mt = migratetype;
+		}
+		set_page_private(page, mt);
 		list = &page->lru;
 	}
 	__mod_zone_page_state(zone, NR_FREE_PAGES, -(i << order));
@@ -1386,8 +1424,12 @@ int split_free_page(struct page *page)
 
 	if (order >= pageblock_order - 1) {
 		struct page *endpage = page + (1 << order) - 1;
-		for (; page < endpage; page += pageblock_nr_pages)
-			set_pageblock_migratetype(page, MIGRATE_MOVABLE);
+		for (; page < endpage; page += pageblock_nr_pages) {
+			int mt = get_pageblock_migratetype(page);
+			if (mt != MIGRATE_ISOLATE && !is_migrate_cma(mt))
+				set_pageblock_migratetype(page,
+							  MIGRATE_MOVABLE);
+		}
 	}
 
 	return 1 << order;
@@ -5427,14 +5469,16 @@ static int
 __count_immobile_pages(struct zone *zone, struct page *page, int count)
 {
 	unsigned long pfn, iter, found;
+	int mt;
+
 	/*
 	 * For avoiding noise data, lru_add_drain_all() should be called
 	 * If ZONE_MOVABLE, the zone never contains immobile pages
 	 */
 	if (zone_idx(zone) == ZONE_MOVABLE)
 		return true;
-
-	if (get_pageblock_migratetype(page) == MIGRATE_MOVABLE)
+	mt = get_pageblock_migratetype(page);
+	if (mt == MIGRATE_MOVABLE || is_migrate_cma(mt))
 		return true;
 
 	pfn = page_to_pfn(page);
diff --git a/mm/vmstat.c b/mm/vmstat.c
index f600557..c47ac13 100644
--- a/mm/vmstat.c
+++ b/mm/vmstat.c
@@ -613,6 +613,9 @@ static char * const migratetype_names[MIGRATE_TYPES] = {
 	"Reclaimable",
 	"Movable",
 	"Reserve",
+#ifdef CONFIG_CMA
+	"CMA",
+#endif
 	"Isolate",
 };
 
-- 
1.7.1.569.g6f426

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[PATCHv23 09/16] mm: page_isolation: MIGRATE_CMA isolation functions added

[Marek Szyprowski]

From: Michal Nazarewicz <mina86@mina86.com>

This commit changes various functions that change pages and
pageblocks migrate type between MIGRATE_ISOLATE and
MIGRATE_MOVABLE in such a way as to allow to work with
MIGRATE_CMA migrate type.

Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 include/linux/gfp.h            |    3 ++-
 include/linux/page-isolation.h |   18 +++++++++---------
 mm/memory-failure.c            |    2 +-
 mm/memory_hotplug.c            |    6 +++---
 mm/page_alloc.c                |   18 ++++++++++++------
 mm/page_isolation.c            |   15 ++++++++-------
 6 files changed, 35 insertions(+), 27 deletions(-)

diff --git a/include/linux/gfp.h b/include/linux/gfp.h
index 78d32a7..1e49be4 100644
--- a/include/linux/gfp.h
+++ b/include/linux/gfp.h
@@ -394,7 +394,8 @@ static inline bool pm_suspended_storage(void)
 #ifdef CONFIG_CMA
 
 /* The below functions must be run on a range from a single zone. */
-extern int alloc_contig_range(unsigned long start, unsigned long end);
+extern int alloc_contig_range(unsigned long start, unsigned long end,
+			      unsigned migratetype);
 extern void free_contig_range(unsigned long pfn, unsigned nr_pages);
 
 /* CMA stuff */
diff --git a/include/linux/page-isolation.h b/include/linux/page-isolation.h
index 051c1b1..3bdcab3 100644
--- a/include/linux/page-isolation.h
+++ b/include/linux/page-isolation.h
@@ -3,7 +3,7 @@
 
 /*
  * Changes migrate type in [start_pfn, end_pfn) to be MIGRATE_ISOLATE.
- * If specified range includes migrate types other than MOVABLE,
+ * If specified range includes migrate types other than MOVABLE or CMA,
  * this will fail with -EBUSY.
  *
  * For isolating all pages in the range finally, the caller have to
@@ -11,27 +11,27 @@
  * test it.
  */
 extern int
-start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);
+start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
+			 unsigned migratetype);
 
 /*
  * Changes MIGRATE_ISOLATE to MIGRATE_MOVABLE.
  * target range is [start_pfn, end_pfn)
  */
 extern int
-undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn);
+undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
+			unsigned migratetype);
 
 /*
- * test all pages in [start_pfn, end_pfn)are isolated or not.
+ * Test all pages in [start_pfn, end_pfn) are isolated or not.
  */
-extern int
-test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn);
+int test_pages_isolated(unsigned long start_pfn, unsigned long end_pfn);
 
 /*
- * Internal funcs.Changes pageblock's migrate type.
- * Please use make_pagetype_isolated()/make_pagetype_movable().
+ * Internal functions. Changes pageblock's migrate type.
  */
 extern int set_migratetype_isolate(struct page *page);
-extern void unset_migratetype_isolate(struct page *page);
+extern void unset_migratetype_isolate(struct page *page, unsigned migratetype);
 
 
 #endif
diff --git a/mm/memory-failure.c b/mm/memory-failure.c
index 0f6033b..4eea81e 100644
--- a/mm/memory-failure.c
+++ b/mm/memory-failure.c
@@ -1404,7 +1404,7 @@ static int get_any_page(struct page *p, unsigned long pfn, int flags)
 		/* Not a free page */
 		ret = 1;
 	}
-	unset_migratetype_isolate(p);
+	unset_migratetype_isolate(p, MIGRATE_MOVABLE);
 	unlock_memory_hotplug();
 	return ret;
 }
diff --git a/mm/memory_hotplug.c b/mm/memory_hotplug.c
index 6629faf..fc898cb 100644
--- a/mm/memory_hotplug.c
+++ b/mm/memory_hotplug.c
@@ -891,7 +891,7 @@ static int __ref offline_pages(unsigned long start_pfn,
 	nr_pages = end_pfn - start_pfn;
 
 	/* set above range as isolated */
-	ret = start_isolate_page_range(start_pfn, end_pfn);
+	ret = start_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
 	if (ret)
 		goto out;
 
@@ -956,7 +956,7 @@ repeat:
 	   We cannot do rollback at this point. */
 	offline_isolated_pages(start_pfn, end_pfn);
 	/* reset pagetype flags and makes migrate type to be MOVABLE */
-	undo_isolate_page_range(start_pfn, end_pfn);
+	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
 	/* removal success */
 	zone->present_pages -= offlined_pages;
 	zone->zone_pgdat->node_present_pages -= offlined_pages;
@@ -981,7 +981,7 @@ failed_removal:
 		start_pfn, end_pfn);
 	memory_notify(MEM_CANCEL_OFFLINE, &arg);
 	/* pushback to free area */
-	undo_isolate_page_range(start_pfn, end_pfn);
+	undo_isolate_page_range(start_pfn, end_pfn, MIGRATE_MOVABLE);
 
 out:
 	unlock_memory_hotplug();
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 07bddbe..e590b95 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5595,7 +5595,7 @@ out:
 	return ret;
 }
 
-void unset_migratetype_isolate(struct page *page)
+void unset_migratetype_isolate(struct page *page, unsigned migratetype)
 {
 	struct zone *zone;
 	unsigned long flags;
@@ -5603,8 +5603,8 @@ void unset_migratetype_isolate(struct page *page)
 	spin_lock_irqsave(&zone->lock, flags);
 	if (get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
 		goto out;
-	set_pageblock_migratetype(page, MIGRATE_MOVABLE);
-	move_freepages_block(zone, page, MIGRATE_MOVABLE);
+	set_pageblock_migratetype(page, migratetype);
+	move_freepages_block(zone, page, migratetype);
 out:
 	spin_unlock_irqrestore(&zone->lock, flags);
 }
@@ -5680,6 +5680,10 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
  * alloc_contig_range() -- tries to allocate given range of pages
  * @start:	start PFN to allocate
  * @end:	one-past-the-last PFN to allocate
+ * @migratetype:	migratetype of the underlaying pageblocks (either
+ *			#MIGRATE_MOVABLE or #MIGRATE_CMA).  All pageblocks
+ *			in range must have the same migratetype and it must
+ *			be either of the two.
  *
  * The PFN range does not have to be pageblock or MAX_ORDER_NR_PAGES
  * aligned, however it's the caller's responsibility to guarantee that
@@ -5692,7 +5696,8 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
  * pages which PFN is in [start, end) are allocated for the caller and
  * need to be freed with free_contig_range().
  */
-int alloc_contig_range(unsigned long start, unsigned long end)
+int alloc_contig_range(unsigned long start, unsigned long end,
+		       unsigned migratetype)
 {
 	struct zone *zone = page_zone(pfn_to_page(start));
 	unsigned long outer_start, outer_end;
@@ -5722,7 +5727,8 @@ int alloc_contig_range(unsigned long start, unsigned long end)
 	 */
 
 	ret = start_isolate_page_range(pfn_align_to_maxpage_down(start),
-				       pfn_align_to_maxpage_up(end));
+				       pfn_align_to_maxpage_up(end),
+				       migratetype);
 	if (ret)
 		goto done;
 
@@ -5782,7 +5788,7 @@ int alloc_contig_range(unsigned long start, unsigned long end)
 
 done:
 	undo_isolate_page_range(pfn_align_to_maxpage_down(start),
-				pfn_align_to_maxpage_up(end));
+				pfn_align_to_maxpage_up(end), migratetype);
 	return ret;
 }
 
diff --git a/mm/page_isolation.c b/mm/page_isolation.c
index 4ae42bb..c9f0477 100644
--- a/mm/page_isolation.c
+++ b/mm/page_isolation.c
@@ -24,6 +24,7 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  * to be MIGRATE_ISOLATE.
  * @start_pfn: The lower PFN of the range to be isolated.
  * @end_pfn: The upper PFN of the range to be isolated.
+ * @migratetype: migrate type to set in error recovery.
  *
  * Making page-allocation-type to be MIGRATE_ISOLATE means free pages in
  * the range will never be allocated. Any free pages and pages freed in the
@@ -32,8 +33,8 @@ __first_valid_page(unsigned long pfn, unsigned long nr_pages)
  * start_pfn/end_pfn must be aligned to pageblock_order.
  * Returns 0 on success and -EBUSY if any part of range cannot be isolated.
  */
-int
-start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
+int start_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
+			     unsigned migratetype)
 {
 	unsigned long pfn;
 	unsigned long undo_pfn;
@@ -56,7 +57,7 @@ undo:
 	for (pfn = start_pfn;
 	     pfn < undo_pfn;
 	     pfn += pageblock_nr_pages)
-		unset_migratetype_isolate(pfn_to_page(pfn));
+		unset_migratetype_isolate(pfn_to_page(pfn), migratetype);
 
 	return -EBUSY;
 }
@@ -64,8 +65,8 @@ undo:
 /*
  * Make isolated pages available again.
  */
-int
-undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
+int undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn,
+			    unsigned migratetype)
 {
 	unsigned long pfn;
 	struct page *page;
@@ -77,7 +78,7 @@ undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
 		page = __first_valid_page(pfn, pageblock_nr_pages);
 		if (!page || get_pageblock_migratetype(page) != MIGRATE_ISOLATE)
 			continue;
-		unset_migratetype_isolate(page);
+		unset_migratetype_isolate(page, migratetype);
 	}
 	return 0;
 }
@@ -86,7 +87,7 @@ undo_isolate_page_range(unsigned long start_pfn, unsigned long end_pfn)
  * all pages in [start_pfn...end_pfn) must be in the same zone.
  * zone->lock must be held before call this.
  *
- * Returns 1 if all pages in the range is isolated.
+ * Returns 1 if all pages in the range are isolated.
  */
 static int
 __test_page_isolated_in_pageblock(unsigned long pfn, unsigned long end_pfn)
-- 
1.7.1.569.g6f426

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[PATCHv23 10/16] mm: Serialize access to min_free_kbytes

[Marek Szyprowski]

From: Mel Gorman <mgorman@suse.de>

There is a race between the min_free_kbytes sysctl, memory hotplug
and transparent hugepage support enablement.  Memory hotplug uses a
zonelists_mutex to avoid a race when building zonelists. Reuse it to
serialise watermark updates.

[a.p.zijlstra@chello.nl: Older patch fixed the race with spinlock]
Signed-off-by: Mel Gorman <mgorman@suse.de>
Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
---
 mm/page_alloc.c |   23 +++++++++++++++--------
 1 files changed, 15 insertions(+), 8 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index e590b95..0aa8079 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5027,14 +5027,7 @@ static void setup_per_zone_lowmem_reserve(void)
 	calculate_totalreserve_pages();
 }
 
-/**
- * setup_per_zone_wmarks - called when min_free_kbytes changes
- * or when memory is hot-{added|removed}
- *
- * Ensures that the watermark[min,low,high] values for each zone are set
- * correctly with respect to min_free_kbytes.
- */
-void setup_per_zone_wmarks(void)
+static void __setup_per_zone_wmarks(void)
 {
 	unsigned long pages_min = min_free_kbytes >> (PAGE_SHIFT - 10);
 	unsigned long pages_low = extra_free_kbytes >> (PAGE_SHIFT - 10);
@@ -5095,6 +5088,20 @@ void setup_per_zone_wmarks(void)
 	calculate_totalreserve_pages();
 }
 
+/**
+ * setup_per_zone_wmarks - called when min_free_kbytes changes
+ * or when memory is hot-{added|removed}
+ *
+ * Ensures that the watermark[min,low,high] values for each zone are set
+ * correctly with respect to min_free_kbytes.
+ */
+void setup_per_zone_wmarks(void)
+{
+	mutex_lock(&zonelists_mutex);
+	__setup_per_zone_wmarks();
+	mutex_unlock(&zonelists_mutex);
+}
+
 /*
  * The inactive anon list should be small enough that the VM never has to
  * do too much work, but large enough that each inactive page has a chance
-- 
1.7.1.569.g6f426

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[PATCHv23 11/16] mm: extract reclaim code from __alloc_pages_direct_reclaim()

[Marek Szyprowski]

This patch extracts common reclaim code from __alloc_pages_direct_reclaim()
function to separate function: __perform_reclaim() which can be later used
by alloc_contig_range().

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Cc: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Mel Gorman <mel@csn.ul.ie>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 mm/page_alloc.c |   30 +++++++++++++++++++++---------
 1 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 0aa8079..7a0d286 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2143,16 +2143,13 @@ __alloc_pages_direct_compact(gfp_t gfp_mask, unsigned int order,
 }
 #endif /* CONFIG_COMPACTION */
 
-/* The really slow allocator path where we enter direct reclaim */
-static inline struct page *
-__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
-	struct zonelist *zonelist, enum zone_type high_zoneidx,
-	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
-	int migratetype, unsigned long *did_some_progress)
+/* Perform direct synchronous page reclaim */
+static int
+__perform_reclaim(gfp_t gfp_mask, unsigned int order, struct zonelist *zonelist,
+		  nodemask_t *nodemask)
 {
-	struct page *page = NULL;
 	struct reclaim_state reclaim_state;
-	bool drained = false;
+	int progress;
 
 	cond_resched();
 
@@ -2163,7 +2160,7 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
 	reclaim_state.reclaimed_slab = 0;
 	current->reclaim_state = &reclaim_state;
 
-	*did_some_progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
+	progress = try_to_free_pages(zonelist, order, gfp_mask, nodemask);
 
 	current->reclaim_state = NULL;
 	lockdep_clear_current_reclaim_state();
@@ -2171,6 +2168,21 @@ __alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
 
 	cond_resched();
 
+	return progress;
+}
+
+/* The really slow allocator path where we enter direct reclaim */
+static inline struct page *
+__alloc_pages_direct_reclaim(gfp_t gfp_mask, unsigned int order,
+	struct zonelist *zonelist, enum zone_type high_zoneidx,
+	nodemask_t *nodemask, int alloc_flags, struct zone *preferred_zone,
+	int migratetype, unsigned long *did_some_progress)
+{
+	struct page *page = NULL;
+	bool drained = false;
+
+	*did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
+					       nodemask);
 	if (unlikely(!(*did_some_progress)))
 		return NULL;
 
-- 
1.7.1.569.g6f426

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[PATCHv23 12/16] mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks

[Marek Szyprowski]

alloc_contig_range() performs memory allocation so it also should keep
track on keeping the correct level of memory watermarks. This commit adds
a call to *_slowpath style reclaim to grab enough pages to make sure that
the final collection of contiguous pages from freelists will not starve
the system.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 include/linux/mmzone.h |    9 +++++++
 mm/page_alloc.c        |   62 ++++++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 71 insertions(+), 0 deletions(-)

diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
index 4781f30..77db8c0 100644
--- a/include/linux/mmzone.h
+++ b/include/linux/mmzone.h
@@ -63,8 +63,10 @@ enum {
 
 #ifdef CONFIG_CMA
 #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
+#  define cma_wmark_pages(zone)	zone->min_cma_pages
 #else
 #  define is_migrate_cma(migratetype) false
+#  define cma_wmark_pages(zone) 0
 #endif
 
 #define for_each_migratetype_order(order, type) \
@@ -371,6 +373,13 @@ struct zone {
 	/* see spanned/present_pages for more description */
 	seqlock_t		span_seqlock;
 #endif
+#ifdef CONFIG_CMA
+	/*
+	 * CMA needs to increase watermark levels during the allocation
+	 * process to make sure that the system is not starved.
+	 */
+	unsigned long		min_cma_pages;
+#endif
 	struct free_area	free_area[MAX_ORDER];
 
 #ifndef CONFIG_SPARSEMEM
diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 7a0d286..39cd74f 100644
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -5092,6 +5092,11 @@ static void __setup_per_zone_wmarks(void)
 					low + (min >> 2);
 		zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) +
 					low + (min >> 1);
+
+		zone->watermark[WMARK_MIN] += cma_wmark_pages(zone);
+		zone->watermark[WMARK_LOW] += cma_wmark_pages(zone);
+		zone->watermark[WMARK_HIGH] += cma_wmark_pages(zone);
+
 		setup_zone_migrate_reserve(zone);
 		spin_unlock_irqrestore(&zone->lock, flags);
 	}
@@ -5695,6 +5700,56 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
 	return ret > 0 ? 0 : ret;
 }
 
+/*
+ * Update zone's cma pages counter used for watermark level calculation.
+ */
+static inline void __update_cma_watermarks(struct zone *zone, int count)
+{
+	unsigned long flags;
+	spin_lock_irqsave(&zone->lock, flags);
+	zone->min_cma_pages += count;
+	spin_unlock_irqrestore(&zone->lock, flags);
+	setup_per_zone_wmarks();
+}
+
+/*
+ * Trigger memory pressure bump to reclaim some pages in order to be able to
+ * allocate 'count' pages in single page units. Does similar work as
+ *__alloc_pages_slowpath() function.
+ */
+static int __reclaim_pages(struct zone *zone, gfp_t gfp_mask, int count)
+{
+	enum zone_type high_zoneidx = gfp_zone(gfp_mask);
+	struct zonelist *zonelist = node_zonelist(0, gfp_mask);
+	int did_some_progress = 0;
+	int order = 1;
+	unsigned long watermark;
+
+	/*
+	 * Increase level of watermarks to force kswapd do his job
+	 * to stabilise at new watermark level.
+	 */
+	__update_cma_watermarks(zone, count);
+
+	/* Obey watermarks as if the page was being allocated */
+	watermark = low_wmark_pages(zone) + count;
+	while (!zone_watermark_ok(zone, 0, watermark, 0, 0)) {
+		wake_all_kswapd(order, zonelist, high_zoneidx, zone_idx(zone));
+
+		did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
+						      NULL);
+		if (!did_some_progress) {
+			/* Exhausted what can be done so it's blamo time */
+			out_of_memory(zonelist, gfp_mask, order, NULL);
+		}
+	}
+
+	/* Restore original watermark levels. */
+	__update_cma_watermarks(zone, -count);
+
+	return count;
+}
+
 /**
  * alloc_contig_range() -- tries to allocate given range of pages
  * @start:	start PFN to allocate
@@ -5793,6 +5848,13 @@ int alloc_contig_range(unsigned long start, unsigned long end,
 		goto done;
 	}
 
+	/*
+	 * Reclaim enough pages to make sure that contiguous allocation
+	 * will not starve the system.
+	 */
+	__reclaim_pages(zone, GFP_HIGHUSER_MOVABLE, end-start);
+
+	/* Grab isolated pages from freelists. */
 	outer_end = isolate_freepages_range(outer_start, end);
 	if (!outer_end) {
 		ret = -EBUSY;
-- 
1.7.1.569.g6f426

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Re: [Linaro-mm-sig] [PATCHv23 12/16] mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks

[Barry Song]

2012/2/23 Marek Szyprowski <m.szyprowski@samsung.com>:
> alloc_contig_range() performs memory allocation so it also should keep
> track on keeping the correct level of memory watermarks. This commit adds
> a call to *_slowpath style reclaim to grab enough pages to make sure that
> the final collection of contiguous pages from freelists will not starve
> the system.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> CC: Michal Nazarewicz <mina86@mina86.com>
> Tested-by: Rob Clark <rob.clark@linaro.org>
> Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
> Tested-by: Robert Nelson <robertcnelson@gmail.com>
> ---
>  include/linux/mmzone.h |    9 +++++++
>  mm/page_alloc.c        |   62 ++++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 71 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/mmzone.h b/include/linux/mmzone.h
> index 4781f30..77db8c0 100644
> --- a/include/linux/mmzone.h
> +++ b/include/linux/mmzone.h
> @@ -63,8 +63,10 @@ enum {
>
>  #ifdef CONFIG_CMA
>  #  define is_migrate_cma(migratetype) unlikely((migratetype) == MIGRATE_CMA)
> +#  define cma_wmark_pages(zone)        zone->min_cma_pages
>  #else
>  #  define is_migrate_cma(migratetype) false
> +#  define cma_wmark_pages(zone) 0
>  #endif
>
>  #define for_each_migratetype_order(order, type) \
> @@ -371,6 +373,13 @@ struct zone {
>        /* see spanned/present_pages for more description */
>        seqlock_t               span_seqlock;
>  #endif
> +#ifdef CONFIG_CMA
> +       /*
> +        * CMA needs to increase watermark levels during the allocation
> +        * process to make sure that the system is not starved.
> +        */
> +       unsigned long           min_cma_pages;
> +#endif
>        struct free_area        free_area[MAX_ORDER];
>
>  #ifndef CONFIG_SPARSEMEM
> diff --git a/mm/page_alloc.c b/mm/page_alloc.c
> index 7a0d286..39cd74f 100644
> --- a/mm/page_alloc.c
> +++ b/mm/page_alloc.c
> @@ -5092,6 +5092,11 @@ static void __setup_per_zone_wmarks(void)
>                                        low + (min >> 2);
>                zone->watermark[WMARK_HIGH] = min_wmark_pages(zone) +
>                                        low + (min >> 1);
> +
> +               zone->watermark[WMARK_MIN] += cma_wmark_pages(zone);
> +               zone->watermark[WMARK_LOW] += cma_wmark_pages(zone);
> +               zone->watermark[WMARK_HIGH] += cma_wmark_pages(zone);
> +
>                setup_zone_migrate_reserve(zone);
>                spin_unlock_irqrestore(&zone->lock, flags);
>        }
> @@ -5695,6 +5700,56 @@ static int __alloc_contig_migrate_range(unsigned long start, unsigned long end)
>        return ret > 0 ? 0 : ret;
>  }
>
> +/*
> + * Update zone's cma pages counter used for watermark level calculation.
> + */
> +static inline void __update_cma_watermarks(struct zone *zone, int count)
> +{
> +       unsigned long flags;
> +       spin_lock_irqsave(&zone->lock, flags);
> +       zone->min_cma_pages += count;
> +       spin_unlock_irqrestore(&zone->lock, flags);
> +       setup_per_zone_wmarks();
> +}
> +
> +/*
> + * Trigger memory pressure bump to reclaim some pages in order to be able to
> + * allocate 'count' pages in single page units. Does similar work as
> + *__alloc_pages_slowpath() function.
> + */
> +static int __reclaim_pages(struct zone *zone, gfp_t gfp_mask, int count)
> +{
> +       enum zone_type high_zoneidx = gfp_zone(gfp_mask);
> +       struct zonelist *zonelist = node_zonelist(0, gfp_mask);
> +       int did_some_progress = 0;
> +       int order = 1;
> +       unsigned long watermark;
> +
> +       /*
> +        * Increase level of watermarks to force kswapd do his job
> +        * to stabilise at new watermark level.
> +        */
> +       __update_cma_watermarks(zone, count);
> +
> +       /* Obey watermarks as if the page was being allocated */
> +       watermark = low_wmark_pages(zone) + count;
> +       while (!zone_watermark_ok(zone, 0, watermark, 0, 0)) {
> +               wake_all_kswapd(order, zonelist, high_zoneidx, zone_idx(zone));
> +
> +               did_some_progress = __perform_reclaim(gfp_mask, order, zonelist,
> +                                                     NULL);
> +               if (!did_some_progress) {
> +                       /* Exhausted what can be done so it's blamo time */
> +                       out_of_memory(zonelist, gfp_mask, order, NULL);

out_of_memory() has got another param in the newest next/master tree,
out_of_memory(zonelist, gfp_mask, order, NULL, false) should be OK.

-barry

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Re: [Linaro-mm-sig] [PATCHv23 12/16] mm: trigger page reclaim in alloc_contig_range() to stabilise watermarks

[Sandeep Patil]

> +static int __reclaim_pages(struct zone *zone, gfp_t gfp_mask, int count)
> +{
> +       /*
> +        * Increase level of watermarks to force kswapd do his job
> +        * to stabilise at new watermark level.
> +        */
> +       __update_cma_watermarks(zone, count);
> +
> +       /* Obey watermarks as if the page was being allocated */
> +       watermark = low_wmark_pages(zone) + count;
> +       while (!zone_watermark_ok(zone, 0, watermark, 0, 0)) {

Wouldn't this reclaim (2 * count pages) above low wmark?

You are updating the low wmark first and then adding "count"
for the zone_watermark_ok() check as well ..

Sandeep

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[PATCHv23 13/16] drivers: add Contiguous Memory Allocator

[Marek Szyprowski]

The Contiguous Memory Allocator is a set of helper functions for DMA
mapping framework that improves allocations of contiguous memory chunks.

CMA grabs memory on system boot, marks it with MIGRATE_CMA migrate type
and gives back to the system. Kernel is allowed to allocate only movable
pages within CMA's managed memory so that it can be used for example for
page cache when DMA mapping do not use it. On
dma_alloc_from_contiguous() request such pages are migrated out of CMA
area to free required contiguous block and fulfill the request. This
allows to allocate large contiguous chunks of memory at any time
assuming that there is enough free memory available in the system.

This code is heavily based on earlier works by Michal Nazarewicz.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 Documentation/kernel-parameters.txt  |    5 +
 arch/Kconfig                         |    3 +
 drivers/base/Kconfig                 |   89 ++++++++
 drivers/base/Makefile                |    1 +
 drivers/base/dma-contiguous.c        |  401 ++++++++++++++++++++++++++++++++++
 include/asm-generic/dma-contiguous.h |   28 +++
 include/linux/device.h               |    4 +
 include/linux/dma-contiguous.h       |  110 +++++++++
 8 files changed, 641 insertions(+), 0 deletions(-)
 create mode 100644 drivers/base/dma-contiguous.c
 create mode 100644 include/asm-generic/dma-contiguous.h
 create mode 100644 include/linux/dma-contiguous.h

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 9677556..7369cee 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -508,6 +508,11 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			Also note the kernel might malfunction if you disable
 			some critical bits.
 
+	cma=nn[MG]	[ARM,KNL]
+			Sets the size of kernel global memory area for contiguous
+			memory allocations. For more information, see
+			include/linux/dma-contiguous.h
+
 	cmo_free_hint=	[PPC] Format: { yes | no }
 			Specify whether pages are marked as being inactive
 			when they are freed.  This is used in CMO environments
diff --git a/arch/Kconfig b/arch/Kconfig
index 5e403de..93ec4b5 100644
--- a/arch/Kconfig
+++ b/arch/Kconfig
@@ -134,6 +134,9 @@ config HAVE_ARCH_TRACEHOOK
 config HAVE_DMA_ATTRS
 	bool
 
+config HAVE_DMA_CONTIGUOUS
+	bool
+
 config USE_GENERIC_SMP_HELPERS
 	bool
 
diff --git a/drivers/base/Kconfig b/drivers/base/Kconfig
index 9aa618a..9b21469 100644
--- a/drivers/base/Kconfig
+++ b/drivers/base/Kconfig
@@ -192,4 +192,93 @@ config DMA_SHARED_BUFFER
 	  APIs extension; the file's descriptor can then be passed on to other
 	  driver.
 
+config CMA
+	bool "Contiguous Memory Allocator (EXPERIMENTAL)"
+	depends on HAVE_DMA_CONTIGUOUS && HAVE_MEMBLOCK && EXPERIMENTAL
+	select MIGRATION
+	help
+	  This enables the Contiguous Memory Allocator which allows drivers
+	  to allocate big physically-contiguous blocks of memory for use with
+	  hardware components that do not support I/O map nor scatter-gather.
+
+	  For more information see <include/linux/dma-contiguous.h>.
+	  If unsure, say "n".
+
+if CMA
+
+config CMA_DEBUG
+	bool "CMA debug messages (DEVELOPMENT)"
+	depends on DEBUG_KERNEL
+	help
+	  Turns on debug messages in CMA.  This produces KERN_DEBUG
+	  messages for every CMA call as well as various messages while
+	  processing calls such as dma_alloc_from_contiguous().
+	  This option does not affect warning and error messages.
+
+comment "Default contiguous memory area size:"
+
+config CMA_SIZE_MBYTES
+	int "Size in Mega Bytes"
+	depends on !CMA_SIZE_SEL_PERCENTAGE
+	default 16
+	help
+	  Defines the size (in MiB) of the default memory area for Contiguous
+	  Memory Allocator.
+
+config CMA_SIZE_PERCENTAGE
+	int "Percentage of total memory"
+	depends on !CMA_SIZE_SEL_MBYTES
+	default 10
+	help
+	  Defines the size of the default memory area for Contiguous Memory
+	  Allocator as a percentage of the total memory in the system.
+
+choice
+	prompt "Selected region size"
+	default CMA_SIZE_SEL_ABSOLUTE
+
+config CMA_SIZE_SEL_MBYTES
+	bool "Use mega bytes value only"
+
+config CMA_SIZE_SEL_PERCENTAGE
+	bool "Use percentage value only"
+
+config CMA_SIZE_SEL_MIN
+	bool "Use lower value (minimum)"
+
+config CMA_SIZE_SEL_MAX
+	bool "Use higher value (maximum)"
+
+endchoice
+
+config CMA_ALIGNMENT
+	int "Maximum PAGE_SIZE order of alignment for contiguous buffers"
+	range 4 9
+	default 8
+	help
+	  DMA mapping framework by default aligns all buffers to the smallest
+	  PAGE_SIZE order which is greater than or equal to the requested buffer
+	  size. This works well for buffers up to a few hundreds kilobytes, but
+	  for larger buffers it just a memory waste. With this parameter you can
+	  specify the maximum PAGE_SIZE order for contiguous buffers. Larger
+	  buffers will be aligned only to this specified order. The order is
+	  expressed as a power of two multiplied by the PAGE_SIZE.
+
+	  For example, if your system defaults to 4KiB pages, the order value
+	  of 8 means that the buffers will be aligned up to 1MiB only.
+
+	  If unsure, leave the default value "8".
+
+config CMA_AREAS
+	int "Maximum count of the CMA device-private areas"
+	default 7
+	help
+	  CMA allows to create CMA areas for particular devices. This parameter
+	  sets the maximum number of such device private CMA areas in the
+	  system.
+
+	  If unsure, leave the default value "7".
+
+endif
+
 endmenu
diff --git a/drivers/base/Makefile b/drivers/base/Makefile
index b6d1b9c..5aa2d70 100644
--- a/drivers/base/Makefile
+++ b/drivers/base/Makefile
@@ -6,6 +6,7 @@ obj-y			:= core.o bus.o dd.o syscore.o \
 			   attribute_container.o transport_class.o \
 			   topology.o
 obj-$(CONFIG_DEVTMPFS)	+= devtmpfs.o
+obj-$(CONFIG_CMA) += dma-contiguous.o
 obj-y			+= power/
 obj-$(CONFIG_HAS_DMA)	+= dma-mapping.o
 obj-$(CONFIG_HAVE_GENERIC_DMA_COHERENT) += dma-coherent.o
diff --git a/drivers/base/dma-contiguous.c b/drivers/base/dma-contiguous.c
new file mode 100644
index 0000000..78efb03
--- /dev/null
+++ b/drivers/base/dma-contiguous.c
@@ -0,0 +1,401 @@
+/*
+ * Contiguous Memory Allocator for DMA mapping framework
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+#define pr_fmt(fmt) "cma: " fmt
+
+#ifdef CONFIG_CMA_DEBUG
+#ifndef DEBUG
+#  define DEBUG
+#endif
+#endif
+
+#include <asm/page.h>
+#include <asm/dma-contiguous.h>
+
+#include <linux/memblock.h>
+#include <linux/err.h>
+#include <linux/mm.h>
+#include <linux/mutex.h>
+#include <linux/page-isolation.h>
+#include <linux/slab.h>
+#include <linux/swap.h>
+#include <linux/mm_types.h>
+#include <linux/dma-contiguous.h>
+
+#ifndef SZ_1M
+#define SZ_1M (1 << 20)
+#endif
+
+struct cma {
+	unsigned long	base_pfn;
+	unsigned long	count;
+	unsigned long	*bitmap;
+};
+
+struct cma *dma_contiguous_default_area;
+
+#ifdef CONFIG_CMA_SIZE_MBYTES
+#define CMA_SIZE_MBYTES CONFIG_CMA_SIZE_MBYTES
+#else
+#define CMA_SIZE_MBYTES 0
+#endif
+
+/*
+ * Default global CMA area size can be defined in kernel's .config.
+ * This is usefull mainly for distro maintainers to create a kernel
+ * that works correctly for most supported systems.
+ * The size can be set in bytes or as a percentage of the total memory
+ * in the system.
+ *
+ * Users, who want to set the size of global CMA area for their system
+ * should use cma= kernel parameter.
+ */
+static const unsigned long size_bytes = CMA_SIZE_MBYTES * SZ_1M;
+static long size_cmdline = -1;
+
+static int __init early_cma(char *p)
+{
+	pr_debug("%s(%s)\n", __func__, p);
+	size_cmdline = memparse(p, &p);
+	return 0;
+}
+early_param("cma", early_cma);
+
+#ifdef CONFIG_CMA_SIZE_PERCENTAGE
+
+static unsigned long __init __maybe_unused cma_early_percent_memory(void)
+{
+	struct memblock_region *reg;
+	unsigned long total_pages = 0;
+
+	/*
+	 * We cannot use memblock_phys_mem_size() here, because
+	 * memblock_analyze() has not been called yet.
+	 */
+	for_each_memblock(memory, reg)
+		total_pages += memblock_region_memory_end_pfn(reg) -
+			       memblock_region_memory_base_pfn(reg);
+
+	return (total_pages * CONFIG_CMA_SIZE_PERCENTAGE / 100) << PAGE_SHIFT;
+}
+
+#else
+
+static inline __maybe_unused unsigned long cma_early_percent_memory(void)
+{
+	return 0;
+}
+
+#endif
+
+/**
+ * dma_contiguous_reserve() - reserve area for contiguous memory handling
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ *
+ * This function reserves memory from early allocator. It should be
+ * called by arch specific code once the early allocator (memblock or bootmem)
+ * has been activated and all other subsystems have already allocated/reserved
+ * memory.
+ */
+void __init dma_contiguous_reserve(phys_addr_t limit)
+{
+	unsigned long selected_size = 0;
+
+	pr_debug("%s(limit %08lx)\n", __func__, (unsigned long)limit);
+
+	if (size_cmdline != -1) {
+		selected_size = size_cmdline;
+	} else {
+#ifdef CONFIG_CMA_SIZE_SEL_MBYTES
+		selected_size = size_bytes;
+#elif defined(CONFIG_CMA_SIZE_SEL_PERCENTAGE)
+		selected_size = cma_early_percent_memory();
+#elif defined(CONFIG_CMA_SIZE_SEL_MIN)
+		selected_size = min(size_bytes, cma_early_percent_memory());
+#elif defined(CONFIG_CMA_SIZE_SEL_MAX)
+		selected_size = max(size_bytes, cma_early_percent_memory());
+#endif
+	}
+
+	if (selected_size) {
+		pr_debug("%s: reserving %ld MiB for global area\n", __func__,
+			 selected_size / SZ_1M);
+
+		dma_declare_contiguous(NULL, selected_size, 0, limit);
+	}
+};
+
+static DEFINE_MUTEX(cma_mutex);
+
+static __init int cma_activate_area(unsigned long base_pfn, unsigned long count)
+{
+	unsigned long pfn = base_pfn;
+	unsigned i = count >> pageblock_order;
+	struct zone *zone;
+
+	WARN_ON_ONCE(!pfn_valid(pfn));
+	zone = page_zone(pfn_to_page(pfn));
+
+	do {
+		unsigned j;
+		base_pfn = pfn;
+		for (j = pageblock_nr_pages; j; --j, pfn++) {
+			WARN_ON_ONCE(!pfn_valid(pfn));
+			if (page_zone(pfn_to_page(pfn)) != zone)
+				return -EINVAL;
+		}
+		init_cma_reserved_pageblock(pfn_to_page(base_pfn));
+	} while (--i);
+	return 0;
+}
+
+static __init struct cma *cma_create_area(unsigned long base_pfn,
+				     unsigned long count)
+{
+	int bitmap_size = BITS_TO_LONGS(count) * sizeof(long);
+	struct cma *cma;
+	int ret = -ENOMEM;
+
+	pr_debug("%s(base %08lx, count %lx)\n", __func__, base_pfn, count);
+
+	cma = kmalloc(sizeof *cma, GFP_KERNEL);
+	if (!cma)
+		return ERR_PTR(-ENOMEM);
+
+	cma->base_pfn = base_pfn;
+	cma->count = count;
+	cma->bitmap = kzalloc(bitmap_size, GFP_KERNEL);
+
+	if (!cma->bitmap)
+		goto no_mem;
+
+	ret = cma_activate_area(base_pfn, count);
+	if (ret)
+		goto error;
+
+	pr_debug("%s: returned %p\n", __func__, (void *)cma);
+	return cma;
+
+error:
+	kfree(cma->bitmap);
+no_mem:
+	kfree(cma);
+	return ERR_PTR(ret);
+}
+
+static struct cma_reserved {
+	phys_addr_t start;
+	unsigned long size;
+	struct device *dev;
+} cma_reserved[MAX_CMA_AREAS] __initdata;
+static unsigned cma_reserved_count __initdata;
+
+static int __init cma_init_reserved_areas(void)
+{
+	struct cma_reserved *r = cma_reserved;
+	unsigned i = cma_reserved_count;
+
+	pr_debug("%s()\n", __func__);
+
+	for (; i; --i, ++r) {
+		struct cma *cma;
+		cma = cma_create_area(PFN_DOWN(r->start),
+				      r->size >> PAGE_SHIFT);
+		if (!IS_ERR(cma))
+			dev_set_cma_area(r->dev, cma);
+	}
+	return 0;
+}
+core_initcall(cma_init_reserved_areas);
+
+/**
+ * dma_declare_contiguous() - reserve area for contiguous memory handling
+ *			      for particular device
+ * @dev:   Pointer to device structure.
+ * @size:  Size of the reserved memory.
+ * @base:  Start address of the reserved memory (optional, 0 for any).
+ * @limit: End address of the reserved memory (optional, 0 for any).
+ *
+ * This function reserves memory for specified device. It should be
+ * called by board specific code when early allocator (memblock or bootmem)
+ * is still activate.
+ */
+int __init dma_declare_contiguous(struct device *dev, unsigned long size,
+				  phys_addr_t base, phys_addr_t limit)
+{
+	struct cma_reserved *r = &cma_reserved[cma_reserved_count];
+	unsigned long alignment;
+
+	pr_debug("%s(size %lx, base %08lx, limit %08lx)\n", __func__,
+		 (unsigned long)size, (unsigned long)base,
+		 (unsigned long)limit);
+
+	/* Sanity checks */
+	if (cma_reserved_count == ARRAY_SIZE(cma_reserved)) {
+		pr_err("Not enough slots for CMA reserved regions!\n");
+		return -ENOSPC;
+	}
+
+	if (!size)
+		return -EINVAL;
+
+	/* Sanitise input arguments */
+	alignment = PAGE_SIZE << max(MAX_ORDER, pageblock_order);
+	base = ALIGN(base, alignment);
+	size = ALIGN(size, alignment);
+	limit &= ~(alignment - 1);
+
+	/* Reserve memory */
+	if (base) {
+		if (memblock_is_region_reserved(base, size) ||
+		    memblock_reserve(base, size) < 0) {
+			base = -EBUSY;
+			goto err;
+		}
+	} else {
+		/*
+		 * Use __memblock_alloc_base() since
+		 * memblock_alloc_base() panic()s.
+		 */
+		phys_addr_t addr = __memblock_alloc_base(size, alignment, limit);
+		if (!addr) {
+			base = -ENOMEM;
+			goto err;
+		} else if (addr + size > ~(unsigned long)0) {
+			memblock_free(addr, size);
+			base = -EINVAL;
+			goto err;
+		} else {
+			base = addr;
+		}
+	}
+
+	/*
+	 * Each reserved area must be initialised later, when more kernel
+	 * subsystems (like slab allocator) are available.
+	 */
+	r->start = base;
+	r->size = size;
+	r->dev = dev;
+	cma_reserved_count++;
+	pr_info("CMA: reserved %ld MiB at %08lx\n", size / SZ_1M,
+		(unsigned long)base);
+
+	/* Architecture specific contiguous memory fixup. */
+	dma_contiguous_early_fixup(base, size);
+	return 0;
+err:
+	pr_err("CMA: failed to reserve %ld MiB\n", size / SZ_1M);
+	return base;
+}
+
+/**
+ * dma_alloc_from_contiguous() - allocate pages from contiguous area
+ * @dev:   Pointer to device for which the allocation is performed.
+ * @count: Requested number of pages.
+ * @align: Requested alignment of pages (in PAGE_SIZE order).
+ *
+ * This function allocates memory buffer for specified device. It uses
+ * device specific contiguous memory area if available or the default
+ * global one. Requires architecture specific get_dev_cma_area() helper
+ * function.
+ */
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int align)
+{
+	unsigned long mask, pfn, pageno, start = 0;
+	struct cma *cma = dev_get_cma_area(dev);
+	int ret;
+
+	if (!cma || !cma->count)
+		return NULL;
+
+	if (align > CONFIG_CMA_ALIGNMENT)
+		align = CONFIG_CMA_ALIGNMENT;
+
+	pr_debug("%s(cma %p, count %d, align %d)\n", __func__, (void *)cma,
+		 count, align);
+
+	if (!count)
+		return NULL;
+
+	mask = (1 << align) - 1;
+
+	mutex_lock(&cma_mutex);
+
+	for (;;) {
+		pageno = bitmap_find_next_zero_area(cma->bitmap, cma->count,
+						    start, count, mask);
+		if (pageno >= cma->count) {
+			ret = -ENOMEM;
+			goto error;
+		}
+
+		pfn = cma->base_pfn + pageno;
+		ret = alloc_contig_range(pfn, pfn + count, MIGRATE_CMA);
+		if (ret == 0) {
+			bitmap_set(cma->bitmap, pageno, count);
+			break;
+		} else if (ret != -EBUSY) {
+			goto error;
+		}
+		pr_debug("%s(): memory range at %p is busy, retrying\n",
+			 __func__, pfn_to_page(pfn));
+		/* try again with a bit different memory target */
+		start = pageno + mask + 1;
+	}
+
+	mutex_unlock(&cma_mutex);
+
+	pr_debug("%s(): returned %p\n", __func__, pfn_to_page(pfn));
+	return pfn_to_page(pfn);
+error:
+	mutex_unlock(&cma_mutex);
+	return NULL;
+}
+
+/**
+ * dma_release_from_contiguous() - release allocated pages
+ * @dev:   Pointer to device for which the pages were allocated.
+ * @pages: Allocated pages.
+ * @count: Number of allocated pages.
+ *
+ * This function releases memory allocated by dma_alloc_from_contiguous().
+ * It returns false when provided pages do not belong to contiguous area and
+ * true otherwise.
+ */
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	struct cma *cma = dev_get_cma_area(dev);
+	unsigned long pfn;
+
+	if (!cma || !pages)
+		return false;
+
+	pr_debug("%s(page %p)\n", __func__, (void *)pages);
+
+	pfn = page_to_pfn(pages);
+
+	if (pfn < cma->base_pfn || pfn >= cma->base_pfn + cma->count)
+		return false;
+
+	VM_BUG_ON(pfn + count > cma->base_pfn + cma->count);
+
+	mutex_lock(&cma_mutex);
+	bitmap_clear(cma->bitmap, pfn - cma->base_pfn, count);
+	free_contig_range(pfn, count);
+	mutex_unlock(&cma_mutex);
+
+	return true;
+}
diff --git a/include/asm-generic/dma-contiguous.h b/include/asm-generic/dma-contiguous.h
new file mode 100644
index 0000000..c544356
--- /dev/null
+++ b/include/asm-generic/dma-contiguous.h
@@ -0,0 +1,28 @@
+#ifndef ASM_DMA_CONTIGUOUS_H
+#define ASM_DMA_CONTIGUOUS_H
+
+#ifdef __KERNEL__
+#ifdef CONFIG_CMA
+
+#include <linux/device.h>
+#include <linux/dma-contiguous.h>
+
+static inline struct cma *dev_get_cma_area(struct device *dev)
+{
+	if (dev && dev->cma_area)
+		return dev->cma_area;
+	return dma_contiguous_default_area;
+}
+
+static inline void dev_set_cma_area(struct device *dev, struct cma *cma)
+{
+	if (dev)
+		dev->cma_area = cma;
+	if (!dev || !dma_contiguous_default_area)
+		dma_contiguous_default_area = cma;
+}
+
+#endif
+#endif
+
+#endif
diff --git a/include/linux/device.h b/include/linux/device.h
index f62e216..f0d8fad 100644
--- a/include/linux/device.h
+++ b/include/linux/device.h
@@ -665,6 +665,10 @@ struct device {
 
 	struct dma_coherent_mem	*dma_mem; /* internal for coherent mem
 					     override */
+#ifdef CONFIG_CMA
+	struct cma *cma_area;		/* contiguous memory area for dma
+					   allocations */
+#endif
 	/* arch specific additions */
 	struct dev_archdata	archdata;
 
diff --git a/include/linux/dma-contiguous.h b/include/linux/dma-contiguous.h
new file mode 100644
index 0000000..2f303e4
--- /dev/null
+++ b/include/linux/dma-contiguous.h
@@ -0,0 +1,110 @@
+#ifndef __LINUX_CMA_H
+#define __LINUX_CMA_H
+
+/*
+ * Contiguous Memory Allocator for DMA mapping framework
+ * Copyright (c) 2010-2011 by Samsung Electronics.
+ * Written by:
+ *	Marek Szyprowski <m.szyprowski@samsung.com>
+ *	Michal Nazarewicz <mina86@mina86.com>
+ *
+ * This program is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License or (at your optional) any later version of the license.
+ */
+
+/*
+ * Contiguous Memory Allocator
+ *
+ *   The Contiguous Memory Allocator (CMA) makes it possible to
+ *   allocate big contiguous chunks of memory after the system has
+ *   booted.
+ *
+ * Why is it needed?
+ *
+ *   Various devices on embedded systems have no scatter-getter and/or
+ *   IO map support and require contiguous blocks of memory to
+ *   operate.  They include devices such as cameras, hardware video
+ *   coders, etc.
+ *
+ *   Such devices often require big memory buffers (a full HD frame
+ *   is, for instance, more then 2 mega pixels large, i.e. more than 6
+ *   MB of memory), which makes mechanisms such as kmalloc() or
+ *   alloc_page() ineffective.
+ *
+ *   At the same time, a solution where a big memory region is
+ *   reserved for a device is suboptimal since often more memory is
+ *   reserved then strictly required and, moreover, the memory is
+ *   inaccessible to page system even if device drivers don't use it.
+ *
+ *   CMA tries to solve this issue by operating on memory regions
+ *   where only movable pages can be allocated from.  This way, kernel
+ *   can use the memory for pagecache and when device driver requests
+ *   it, allocated pages can be migrated.
+ *
+ * Driver usage
+ *
+ *   CMA should not be used by the device drivers directly. It is
+ *   only a helper framework for dma-mapping subsystem.
+ *
+ *   For more information, see kernel-docs in drivers/base/dma-contiguous.c
+ */
+
+#ifdef __KERNEL__
+
+struct cma;
+struct page;
+struct device;
+
+#ifdef CONFIG_CMA
+
+/*
+ * There is always at least global CMA area and a few optional device
+ * private areas configured in kernel .config.
+ */
+#define MAX_CMA_AREAS	(1 + CONFIG_CMA_AREAS)
+
+extern struct cma *dma_contiguous_default_area;
+
+void dma_contiguous_reserve(phys_addr_t addr_limit);
+int dma_declare_contiguous(struct device *dev, unsigned long size,
+			   phys_addr_t base, phys_addr_t limit);
+
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int order);
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count);
+
+#else
+
+#define MAX_CMA_AREAS	(0)
+
+static inline void dma_contiguous_reserve(phys_addr_t limit) { }
+
+static inline
+int dma_declare_contiguous(struct device *dev, unsigned long size,
+			   phys_addr_t base, phys_addr_t limit)
+{
+	return -ENOSYS;
+}
+
+static inline
+struct page *dma_alloc_from_contiguous(struct device *dev, int count,
+				       unsigned int order)
+{
+	return NULL;
+}
+
+static inline
+bool dma_release_from_contiguous(struct device *dev, struct page *pages,
+				 int count)
+{
+	return false;
+}
+
+#endif
+
+#endif
+
+#endif
-- 
1.7.1.569.g6f426

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Re: [Linaro-mm-sig] [PATCHv23 13/16] drivers: add Contiguous Memory Allocator

[Barry Song]

2012/2/23 Marek Szyprowski <m.szyprowski@samsung.com>:
> The Contiguous Memory Allocator is a set of helper functions for DMA
> mapping framework that improves allocations of contiguous memory chunks.
>
> CMA grabs memory on system boot, marks it with MIGRATE_CMA migrate type
> and gives back to the system. Kernel is allowed to allocate only movable
> pages within CMA's managed memory so that it can be used for example for
> page cache when DMA mapping do not use it. On
> dma_alloc_from_contiguous() request such pages are migrated out of CMA
> area to free required contiguous block and fulfill the request. This
> allows to allocate large contiguous chunks of memory at any time
> assuming that there is enough free memory available in the system.
>
> This code is heavily based on earlier works by Michal Nazarewicz.
>
> Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
> Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
> Signed-off-by: Michal Nazarewicz <mina86@mina86.com>
> Acked-by: Arnd Bergmann <arnd@arndb.de>
> Tested-by: Rob Clark <rob.clark@linaro.org>
> Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
> Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
> Tested-by: Robert Nelson <robertcnelson@gmail.com>

if there is a /proc/cmainfo like /proc/slabinfo, it might be helpful
to people as we can see the usage of CMA clearly.

Thanks
barry

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[PATCHv23 14/16] X86: integrate CMA with DMA-mapping subsystem

[Marek Szyprowski]

This patch adds support for CMA to dma-mapping subsystem for x86
architecture that uses common pci-dma/pci-nommu implementation. This
allows to test CMA on KVM/QEMU and a lot of common x86 boxes.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/x86/Kconfig                      |    1 +
 arch/x86/include/asm/dma-contiguous.h |   13 +++++++++++++
 arch/x86/include/asm/dma-mapping.h    |    4 ++++
 arch/x86/kernel/pci-dma.c             |   18 ++++++++++++++++--
 arch/x86/kernel/pci-nommu.c           |    8 +-------
 arch/x86/kernel/setup.c               |    2 ++
 6 files changed, 37 insertions(+), 9 deletions(-)
 create mode 100644 arch/x86/include/asm/dma-contiguous.h

diff --git a/arch/x86/Kconfig b/arch/x86/Kconfig
index a61db6d..fea7f3a 100644
--- a/arch/x86/Kconfig
+++ b/arch/x86/Kconfig
@@ -31,6 +31,7 @@ config X86
 	select ARCH_WANT_OPTIONAL_GPIOLIB
 	select ARCH_WANT_FRAME_POINTERS
 	select HAVE_DMA_ATTRS
+	select HAVE_DMA_CONTIGUOUS if !SWIOTLB
 	select HAVE_KRETPROBES
 	select HAVE_OPTPROBES
 	select HAVE_FTRACE_MCOUNT_RECORD
diff --git a/arch/x86/include/asm/dma-contiguous.h b/arch/x86/include/asm/dma-contiguous.h
new file mode 100644
index 0000000..c092416
--- /dev/null
+++ b/arch/x86/include/asm/dma-contiguous.h
@@ -0,0 +1,13 @@
+#ifndef ASMX86_DMA_CONTIGUOUS_H
+#define ASMX86_DMA_CONTIGUOUS_H
+
+#ifdef __KERNEL__
+
+#include <linux/types.h>
+#include <asm-generic/dma-contiguous.h>
+
+static inline void
+dma_contiguous_early_fixup(phys_addr_t base, unsigned long size) { }
+
+#endif
+#endif
diff --git a/arch/x86/include/asm/dma-mapping.h b/arch/x86/include/asm/dma-mapping.h
index 4b4331d..8ca32d4 100644
--- a/arch/x86/include/asm/dma-mapping.h
+++ b/arch/x86/include/asm/dma-mapping.h
@@ -13,6 +13,7 @@
 #include <asm/io.h>
 #include <asm/swiotlb.h>
 #include <asm-generic/dma-coherent.h>
+#include <linux/dma-contiguous.h>
 
 #ifdef CONFIG_ISA
 # define ISA_DMA_BIT_MASK DMA_BIT_MASK(24)
@@ -62,6 +63,9 @@ extern void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 					dma_addr_t *dma_addr, gfp_t flag,
 					struct dma_attrs *attrs);
 
+extern void dma_generic_free_coherent(struct device *dev, size_t size,
+				      void *vaddr, dma_addr_t dma_addr);
+
 static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
 {
 	if (!dev->dma_mask)
diff --git a/arch/x86/kernel/pci-dma.c b/arch/x86/kernel/pci-dma.c
index 75e1cc1..caba818 100644
--- a/arch/x86/kernel/pci-dma.c
+++ b/arch/x86/kernel/pci-dma.c
@@ -100,14 +100,18 @@ void *dma_generic_alloc_coherent(struct device *dev, size_t size,
 				 struct dma_attrs *attrs)
 {
 	unsigned long dma_mask;
-	struct page *page;
+	struct page *page = NULL;
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
 	dma_addr_t addr;
 
 	dma_mask = dma_alloc_coherent_mask(dev, flag);
 
 	flag |= __GFP_ZERO;
 again:
-	page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
+	if (!(flag & GFP_ATOMIC))
+		page = dma_alloc_from_contiguous(dev, count, get_order(size));
+	if (!page)
+		page = alloc_pages_node(dev_to_node(dev), flag, get_order(size));
 	if (!page)
 		return NULL;
 
@@ -127,6 +131,16 @@ again:
 	return page_address(page);
 }
 
+void dma_generic_free_coherent(struct device *dev, size_t size, void *vaddr,
+			       dma_addr_t dma_addr, struct dma_attrs *attrs)
+{
+	unsigned int count = PAGE_ALIGN(size) >> PAGE_SHIFT;
+	struct page *page = virt_to_page(vaddr);
+
+	if (!dma_release_from_contiguous(dev, page, count))
+		free_pages((unsigned long)vaddr, get_order(size));
+}
+
 /*
  * See <Documentation/x86/x86_64/boot-options.txt> for the iommu kernel
  * parameter documentation.
diff --git a/arch/x86/kernel/pci-nommu.c b/arch/x86/kernel/pci-nommu.c
index f960506..871be4a 100644
--- a/arch/x86/kernel/pci-nommu.c
+++ b/arch/x86/kernel/pci-nommu.c
@@ -74,12 +74,6 @@ static int nommu_map_sg(struct device *hwdev, struct scatterlist *sg,
 	return nents;
 }
 
-static void nommu_free_coherent(struct device *dev, size_t size, void *vaddr,
-				dma_addr_t dma_addr, struct dma_attrs *attrs)
-{
-	free_pages((unsigned long)vaddr, get_order(size));
-}
-
 static void nommu_sync_single_for_device(struct device *dev,
 			dma_addr_t addr, size_t size,
 			enum dma_data_direction dir)
@@ -97,7 +91,7 @@ static void nommu_sync_sg_for_device(struct device *dev,
 
 struct dma_map_ops nommu_dma_ops = {
 	.alloc			= dma_generic_alloc_coherent,
-	.free			= nommu_free_coherent,
+	.free			= dma_generic_free_coherent,
 	.map_sg			= nommu_map_sg,
 	.map_page		= nommu_map_page,
 	.sync_single_for_device = nommu_sync_single_for_device,
diff --git a/arch/x86/kernel/setup.c b/arch/x86/kernel/setup.c
index e22bb08..d20ef5b 100644
--- a/arch/x86/kernel/setup.c
+++ b/arch/x86/kernel/setup.c
@@ -50,6 +50,7 @@
 #include <asm/pci-direct.h>
 #include <linux/init_ohci1394_dma.h>
 #include <linux/kvm_para.h>
+#include <linux/dma-contiguous.h>
 
 #include <linux/errno.h>
 #include <linux/kernel.h>
@@ -957,6 +958,7 @@ void __init setup_arch(char **cmdline_p)
 	}
 #endif
 	memblock.current_limit = get_max_mapped();
+	dma_contiguous_reserve(0);
 
 	/*
 	 * NOTE: On x86-32, only from this point on, fixmaps are ready for use.
-- 
1.7.1.569.g6f426

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[PATCHv23 15/16] ARM: integrate CMA with DMA-mapping subsystem

[Marek Szyprowski]

This patch adds support for CMA to dma-mapping subsystem for ARM
architecture. By default a global CMA area is used, but specific devices
are allowed to have their private memory areas if required (they can be
created with dma_declare_contiguous() function during board
initialisation).

Contiguous memory areas reserved for DMA are remapped with 2-level page
tables on boot. Once a buffer is requested, a low memory kernel mapping
is updated to to match requested memory access type.

GFP_ATOMIC allocations are performed from special pool which is created
early during boot. This way remapping page attributes is not needed on
allocation time.

CMA has been enabled unconditionally for ARMv6+ systems.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
CC: Michal Nazarewicz <mina86@mina86.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
Tested-by: Rob Clark <rob.clark@linaro.org>
Tested-by: Ohad Ben-Cohen <ohad@wizery.com>
Tested-by: Benjamin Gaignard <benjamin.gaignard@linaro.org>
Tested-by: Robert Nelson <robertcnelson@gmail.com>
---
 Documentation/kernel-parameters.txt   |    4 +
 arch/arm/Kconfig                      |    2 +
 arch/arm/include/asm/dma-contiguous.h |   15 ++
 arch/arm/include/asm/mach/map.h       |    1 +
 arch/arm/kernel/setup.c               |    9 +-
 arch/arm/mm/dma-mapping.c             |  369 +++++++++++++++++++++++++++------
 arch/arm/mm/init.c                    |   23 ++-
 arch/arm/mm/mm.h                      |    3 +
 arch/arm/mm/mmu.c                     |   31 ++-
 9 files changed, 369 insertions(+), 88 deletions(-)
 create mode 100644 arch/arm/include/asm/dma-contiguous.h

diff --git a/Documentation/kernel-parameters.txt b/Documentation/kernel-parameters.txt
index 7369cee..24c1fa9 100644
--- a/Documentation/kernel-parameters.txt
+++ b/Documentation/kernel-parameters.txt
@@ -520,6 +520,10 @@ bytes respectively. Such letter suffixes can also be entirely omitted.
 			a hypervisor.
 			Default: yes
 
+	coherent_pool=nn[KMG]	[ARM,KNL]
+			Sets the size of memory pool for coherent, atomic dma
+			allocations if Contiguous Memory Allocator (CMA) is used.
+
 	code_bytes	[X86] How many bytes of object code to print
 			in an oops report.
 			Range: 0 - 8192
diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig
index e3ccbc3..8a5ca22 100644
--- a/arch/arm/Kconfig
+++ b/arch/arm/Kconfig
@@ -4,6 +4,8 @@ config ARM
 	select HAVE_AOUT
 	select HAVE_DMA_API_DEBUG
 	select HAVE_IDE if PCI || ISA || PCMCIA
+	select HAVE_DMA_CONTIGUOUS if (CPU_V6 || CPU_V6K || CPU_V7)
+	select CMA if (CPU_V6 || CPU_V6K || CPU_V7)
 	select HAVE_MEMBLOCK
 	select RTC_LIB
 	select SYS_SUPPORTS_APM_EMULATION
diff --git a/arch/arm/include/asm/dma-contiguous.h b/arch/arm/include/asm/dma-contiguous.h
new file mode 100644
index 0000000..3ed37b4
--- /dev/null
+++ b/arch/arm/include/asm/dma-contiguous.h
@@ -0,0 +1,15 @@
+#ifndef ASMARM_DMA_CONTIGUOUS_H
+#define ASMARM_DMA_CONTIGUOUS_H
+
+#ifdef __KERNEL__
+#ifdef CONFIG_CMA
+
+#include <linux/types.h>
+#include <asm-generic/dma-contiguous.h>
+
+void dma_contiguous_early_fixup(phys_addr_t base, unsigned long size);
+
+#endif
+#endif
+
+#endif
diff --git a/arch/arm/include/asm/mach/map.h b/arch/arm/include/asm/mach/map.h
index b36f365..a6efcdd 100644
--- a/arch/arm/include/asm/mach/map.h
+++ b/arch/arm/include/asm/mach/map.h
@@ -30,6 +30,7 @@ struct map_desc {
 #define MT_MEMORY_DTCM		12
 #define MT_MEMORY_ITCM		13
 #define MT_MEMORY_SO		14
+#define MT_MEMORY_DMA_READY	15
 
 #ifdef CONFIG_MMU
 extern void iotable_init(struct map_desc *, int);
diff --git a/arch/arm/kernel/setup.c b/arch/arm/kernel/setup.c
index 10303b3..ae5ca1b 100644
--- a/arch/arm/kernel/setup.c
+++ b/arch/arm/kernel/setup.c
@@ -79,6 +79,7 @@ __setup("fpe=", fpe_setup);
 extern void paging_init(struct machine_desc *desc);
 extern void sanity_check_meminfo(void);
 extern void reboot_setup(char *str);
+extern void setup_dma_zone(struct machine_desc *desc);
 
 unsigned int processor_id;
 EXPORT_SYMBOL(processor_id);
@@ -923,12 +924,8 @@ void __init setup_arch(char **cmdline_p)
 	machine_desc = mdesc;
 	machine_name = mdesc->name;
 
-#ifdef CONFIG_ZONE_DMA
-	if (mdesc->dma_zone_size) {
-		extern unsigned long arm_dma_zone_size;
-		arm_dma_zone_size = mdesc->dma_zone_size;
-	}
-#endif
+	setup_dma_zone(mdesc);
+
 	if (mdesc->restart_mode)
 		reboot_setup(&mdesc->restart_mode);
 
diff --git a/arch/arm/mm/dma-mapping.c b/arch/arm/mm/dma-mapping.c
index db23ae4..5e3882f 100644
--- a/arch/arm/mm/dma-mapping.c
+++ b/arch/arm/mm/dma-mapping.c
@@ -17,7 +17,9 @@
 #include <linux/init.h>
 #include <linux/device.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-contiguous.h>
 #include <linux/highmem.h>
+#include <linux/memblock.h>
 #include <linux/slab.h>
 
 #include <asm/memory.h>
@@ -26,6 +28,8 @@
 #include <asm/tlbflush.h>
 #include <asm/sizes.h>
 #include <asm/mach/arch.h>
+#include <asm/mach/map.h>
+#include <asm/dma-contiguous.h>
 
 #include "mm.h"
 
@@ -56,6 +60,19 @@ static u64 get_coherent_dma_mask(struct device *dev)
 	return mask;
 }
 
+static void __dma_clear_buffer(struct page *page, size_t size)
+{
+	void *ptr;
+	/*
+	 * Ensure that the allocated pages are zeroed, and that any data
+	 * lurking in the kernel direct-mapped region is invalidated.
+	 */
+	ptr = page_address(page);
+	memset(ptr, 0, size);
+	dmac_flush_range(ptr, ptr + size);
+	outer_flush_range(__pa(ptr), __pa(ptr) + size);
+}
+
 /*
  * Allocate a DMA buffer for 'dev' of size 'size' using the
  * specified gfp mask.  Note that 'size' must be page aligned.
@@ -64,23 +81,6 @@ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gf
 {
 	unsigned long order = get_order(size);
 	struct page *page, *p, *e;
-	void *ptr;
-	u64 mask = get_coherent_dma_mask(dev);
-
-#ifdef CONFIG_DMA_API_DEBUG
-	u64 limit = (mask + 1) & ~mask;
-	if (limit && size >= limit) {
-		dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
-			size, mask);
-		return NULL;
-	}
-#endif
-
-	if (!mask)
-		return NULL;
-
-	if (mask < 0xffffffffULL)
-		gfp |= GFP_DMA;
 
 	page = alloc_pages(gfp, order);
 	if (!page)
@@ -93,14 +93,7 @@ static struct page *__dma_alloc_buffer(struct device *dev, size_t size, gfp_t gf
 	for (p = page + (size >> PAGE_SHIFT), e = page + (1 << order); p < e; p++)
 		__free_page(p);
 
-	/*
-	 * Ensure that the allocated pages are zeroed, and that any data
-	 * lurking in the kernel direct-mapped region is invalidated.
-	 */
-	ptr = page_address(page);
-	memset(ptr, 0, size);
-	dmac_flush_range(ptr, ptr + size);
-	outer_flush_range(__pa(ptr), __pa(ptr) + size);
+	__dma_clear_buffer(page, size);
 
 	return page;
 }
@@ -170,6 +163,9 @@ static int __init consistent_init(void)
 	unsigned long base = consistent_base;
 	unsigned long num_ptes = (CONSISTENT_END - base) >> PMD_SHIFT;
 
+	if (cpu_architecture() >= CPU_ARCH_ARMv6)
+		return 0;
+
 	consistent_pte = kmalloc(num_ptes * sizeof(pte_t), GFP_KERNEL);
 	if (!consistent_pte) {
 		pr_err("%s: no memory\n", __func__);
@@ -210,9 +206,101 @@ static int __init consistent_init(void)
 
 	return ret;
 }
-
 core_initcall(consistent_init);
 
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page);
+
+static struct arm_vmregion_head coherent_head = {
+	.vm_lock	= __SPIN_LOCK_UNLOCKED(&coherent_head.vm_lock),
+	.vm_list	= LIST_HEAD_INIT(coherent_head.vm_list),
+};
+
+size_t coherent_pool_size = DEFAULT_CONSISTENT_DMA_SIZE / 8;
+
+static int __init early_coherent_pool(char *p)
+{
+	coherent_pool_size = memparse(p, &p);
+	return 0;
+}
+early_param("coherent_pool", early_coherent_pool);
+
+/*
+ * Initialise the coherent pool for atomic allocations.
+ */
+static int __init coherent_init(void)
+{
+	pgprot_t prot = pgprot_dmacoherent(pgprot_kernel);
+	size_t size = coherent_pool_size;
+	struct page *page;
+	void *ptr;
+
+	if (cpu_architecture() < CPU_ARCH_ARMv6)
+		return 0;
+
+	ptr = __alloc_from_contiguous(NULL, size, prot, &page);
+	if (ptr) {
+		coherent_head.vm_start = (unsigned long) ptr;
+		coherent_head.vm_end = (unsigned long) ptr + size;
+		printk(KERN_INFO "DMA: preallocated %u KiB pool for atomic coherent allocations\n",
+		       (unsigned)size / 1024);
+		return 0;
+	}
+	printk(KERN_ERR "DMA: failed to allocate %u KiB pool for atomic coherent allocation\n",
+	       (unsigned)size / 1024);
+	return -ENOMEM;
+}
+/*
+ * CMA is activated by core_initcall, so we must be called after it.
+ */
+postcore_initcall(coherent_init);
+
+struct dma_contig_early_reserve {
+	phys_addr_t base;
+	unsigned long size;
+};
+
+static struct dma_contig_early_reserve dma_mmu_remap[MAX_CMA_AREAS] __initdata;
+
+static int dma_mmu_remap_num __initdata;
+
+void __init dma_contiguous_early_fixup(phys_addr_t base, unsigned long size)
+{
+	dma_mmu_remap[dma_mmu_remap_num].base = base;
+	dma_mmu_remap[dma_mmu_remap_num].size = size;
+	dma_mmu_remap_num++;
+}
+
+void __init dma_contiguous_remap(void)
+{
+	int i;
+	for (i = 0; i < dma_mmu_remap_num; i++) {
+		phys_addr_t start = dma_mmu_remap[i].base;
+		phys_addr_t end = start + dma_mmu_remap[i].size;
+		struct map_desc map;
+		unsigned long addr;
+
+		if (end > arm_lowmem_limit)
+			end = arm_lowmem_limit;
+		if (start >= end)
+			return;
+
+		map.pfn = __phys_to_pfn(start);
+		map.virtual = __phys_to_virt(start);
+		map.length = end - start;
+		map.type = MT_MEMORY_DMA_READY;
+
+		/*
+		 * Clear previous low-memory mapping
+		 */
+		for (addr = __phys_to_virt(start); addr < __phys_to_virt(end);
+		     addr += PGDIR_SIZE)
+			pmd_clear(pmd_off_k(addr));
+
+		iotable_init(&map, 1);
+	}
+}
+
 static void *
 __dma_alloc_remap(struct page *page, size_t size, gfp_t gfp, pgprot_t prot,
 	const void *caller)
@@ -319,20 +407,173 @@ static void __dma_free_remap(void *cpu_addr, size_t size)
 	arm_vmregion_free(&consistent_head, c);
 }
 
+static int __dma_update_pte(pte_t *pte, pgtable_t token, unsigned long addr,
+			    void *data)
+{
+	struct page *page = virt_to_page(addr);
+	pgprot_t prot = *(pgprot_t *)data;
+
+	set_pte_ext(pte, mk_pte(page, prot), 0);
+	return 0;
+}
+
+static void __dma_remap(struct page *page, size_t size, pgprot_t prot)
+{
+	unsigned long start = (unsigned long) page_address(page);
+	unsigned end = start + size;
+
+	apply_to_page_range(&init_mm, start, size, __dma_update_pte, &prot);
+	dsb();
+	flush_tlb_kernel_range(start, end);
+}
+
+static void *__alloc_remap_buffer(struct device *dev, size_t size, gfp_t gfp,
+				 pgprot_t prot, struct page **ret_page,
+				 const void *caller)
+{
+	struct page *page;
+	void *ptr;
+	page = __dma_alloc_buffer(dev, size, gfp);
+	if (!page)
+		return NULL;
+
+	ptr = __dma_alloc_remap(page, size, gfp, prot, caller);
+	if (!ptr) {
+		__dma_free_buffer(page, size);
+		return NULL;
+	}
+
+	*ret_page = page;
+	return ptr;
+}
+
+static void *__alloc_from_pool(struct device *dev, size_t size,
+			       struct page **ret_page, const void *caller)
+{
+	struct arm_vmregion *c;
+	size_t align;
+
+	if (!coherent_head.vm_start) {
+		printk(KERN_ERR "%s: coherent pool not initialised!\n",
+		       __func__);
+		dump_stack();
+		return NULL;
+	}
+
+	/*
+	 * Align the region allocation - allocations from pool are rather
+	 * small, so align them to their order in pages, minimum is a page
+	 * size. This helps reduce fragmentation of the DMA space.
+	 */
+	align = PAGE_SIZE << get_order(size);
+	c = arm_vmregion_alloc(&coherent_head, align, size, 0, caller);
+	if (c) {
+		void *ptr = (void *)c->vm_start;
+		struct page *page = virt_to_page(ptr);
+		*ret_page = page;
+		return ptr;
+	}
+	return NULL;
+}
+
+static int __free_from_pool(void *cpu_addr, size_t size)
+{
+	unsigned long start = (unsigned long)cpu_addr;
+	unsigned long end = start + size;
+	struct arm_vmregion *c;
+
+	if (start < coherent_head.vm_start || end > coherent_head.vm_end)
+		return 0;
+
+	c = arm_vmregion_find_remove(&coherent_head, (unsigned long)start);
+
+	if ((c->vm_end - c->vm_start) != size) {
+		printk(KERN_ERR "%s: freeing wrong coherent size (%ld != %d)\n",
+		       __func__, c->vm_end - c->vm_start, size);
+		dump_stack();
+		size = c->vm_end - c->vm_start;
+	}
+
+	arm_vmregion_free(&coherent_head, c);
+	return 1;
+}
+
+static void *__alloc_from_contiguous(struct device *dev, size_t size,
+				     pgprot_t prot, struct page **ret_page)
+{
+	unsigned long order = get_order(size);
+	size_t count = size >> PAGE_SHIFT;
+	struct page *page;
+
+	page = dma_alloc_from_contiguous(dev, count, order);
+	if (!page)
+		return NULL;
+
+	__dma_clear_buffer(page, size);
+	__dma_remap(page, size, prot);
+
+	*ret_page = page;
+	return page_address(page);
+}
+
+static void __free_from_contiguous(struct device *dev, struct page *page,
+				   size_t size)
+{
+	__dma_remap(page, size, pgprot_kernel);
+	dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT);
+}
+
+#define nommu() 0
+
 #else	/* !CONFIG_MMU */
 
-#define __dma_alloc_remap(page, size, gfp, prot, c)	page_address(page)
-#define __dma_free_remap(addr, size)			do { } while (0)
+#define nommu() 1
+
+#define __alloc_remap_buffer(dev, size, gfp, prot, ret, c)	NULL
+#define __alloc_from_pool(dev, size, ret_page, c)		NULL
+#define __alloc_from_contiguous(dev, size, prot, ret)		NULL
+#define __free_from_pool(cpu_addr, size)			0
+#define __free_from_contiguous(dev, page, size)			do { } while (0)
+#define __dma_free_remap(cpu_addr, size)			do { } while (0)
 
 #endif	/* CONFIG_MMU */
 
-static void *
-__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
-	    pgprot_t prot, const void *caller)
+static void *__alloc_simple_buffer(struct device *dev, size_t size, gfp_t gfp,
+				   struct page **ret_page)
 {
 	struct page *page;
+	page = __dma_alloc_buffer(dev, size, gfp);
+	if (!page)
+		return NULL;
+
+	*ret_page = page;
+	return page_address(page);
+}
+
+
+
+static void *__dma_alloc(struct device *dev, size_t size, dma_addr_t *handle,
+			 gfp_t gfp, pgprot_t prot, const void *caller)
+{
+	u64 mask = get_coherent_dma_mask(dev);
+	struct page *page;
 	void *addr;
 
+#ifdef CONFIG_DMA_API_DEBUG
+	u64 limit = (mask + 1) & ~mask;
+	if (limit && size >= limit) {
+		dev_warn(dev, "coherent allocation too big (requested %#x mask %#llx)\n",
+			size, mask);
+		return NULL;
+	}
+#endif
+
+	if (!mask)
+		return NULL;
+
+	if (mask < 0xffffffffULL)
+		gfp |= GFP_DMA;
+
 	/*
 	 * Following is a work-around (a.k.a. hack) to prevent pages
 	 * with __GFP_COMP being passed to split_page() which cannot
@@ -345,19 +586,17 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
 	*handle = ~0;
 	size = PAGE_ALIGN(size);
 
-	page = __dma_alloc_buffer(dev, size, gfp);
-	if (!page)
-		return NULL;
-
-	if (!arch_is_coherent())
-		addr = __dma_alloc_remap(page, size, gfp, prot, caller);
+	if (arch_is_coherent() || nommu())
+		addr = __alloc_simple_buffer(dev, size, gfp, &page);
+	else if (cpu_architecture() < CPU_ARCH_ARMv6)
+		addr = __alloc_remap_buffer(dev, size, gfp, prot, &page, caller);
+	else if (gfp & GFP_ATOMIC)
+		addr = __alloc_from_pool(dev, size, &page, caller);
 	else
-		addr = page_address(page);
+		addr = __alloc_from_contiguous(dev, size, prot, &page);
 
 	if (addr)
 		*handle = pfn_to_dma(dev, page_to_pfn(page));
-	else
-		__dma_free_buffer(page, size);
 
 	return addr;
 }
@@ -366,8 +605,8 @@ __dma_alloc(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp,
  * Allocate DMA-coherent memory space and return both the kernel remapped
  * virtual and bus address for that space.
  */
-void *
-dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle, gfp_t gfp)
+void *dma_alloc_coherent(struct device *dev, size_t size, dma_addr_t *handle,
+			 gfp_t gfp)
 {
 	void *memory;
 
@@ -398,25 +637,11 @@ static int dma_mmap(struct device *dev, struct vm_area_struct *vma,
 {
 	int ret = -ENXIO;
 #ifdef CONFIG_MMU
-	unsigned long user_size, kern_size;
-	struct arm_vmregion *c;
-
-	user_size = (vma->vm_end - vma->vm_start) >> PAGE_SHIFT;
-
-	c = arm_vmregion_find(&consistent_head, (unsigned long)cpu_addr);
-	if (c) {
-		unsigned long off = vma->vm_pgoff;
-
-		kern_size = (c->vm_end - c->vm_start) >> PAGE_SHIFT;
-
-		if (off < kern_size &&
-		    user_size <= (kern_size - off)) {
-			ret = remap_pfn_range(vma, vma->vm_start,
-					      page_to_pfn(c->vm_pages) + off,
-					      user_size << PAGE_SHIFT,
-					      vma->vm_page_prot);
-		}
-	}
+	unsigned long pfn = dma_to_pfn(dev, dma_addr);
+	ret = remap_pfn_range(vma, vma->vm_start,
+			      pfn + vma->vm_pgoff,
+			      vma->vm_end - vma->vm_start,
+			      vma->vm_page_prot);
 #endif	/* CONFIG_MMU */
 
 	return ret;
@@ -438,23 +663,33 @@ int dma_mmap_writecombine(struct device *dev, struct vm_area_struct *vma,
 }
 EXPORT_SYMBOL(dma_mmap_writecombine);
 
+
 /*
- * free a page as defined by the above mapping.
- * Must not be called with IRQs disabled.
+ * Free a buffer as defined by the above mapping.
  */
 void dma_free_coherent(struct device *dev, size_t size, void *cpu_addr, dma_addr_t handle)
 {
-	WARN_ON(irqs_disabled());
+	struct page *page = pfn_to_page(dma_to_pfn(dev, handle));
 
 	if (dma_release_from_coherent(dev, get_order(size), cpu_addr))
 		return;
 
 	size = PAGE_ALIGN(size);
 
-	if (!arch_is_coherent())
+	if (arch_is_coherent() || nommu()) {
+		__dma_free_buffer(page, size);
+	} else if (cpu_architecture() < CPU_ARCH_ARMv6) {
 		__dma_free_remap(cpu_addr, size);
-
-	__dma_free_buffer(pfn_to_page(dma_to_pfn(dev, handle)), size);
+		__dma_free_buffer(page, size);
+	} else {
+		if (__free_from_pool(cpu_addr, size))
+			return;
+		/*
+		 * Non-atomic allocations cannot be freed with IRQs disabled
+		 */
+		WARN_ON(irqs_disabled());
+		__free_from_contiguous(dev, page, size);
+	}
 }
 EXPORT_SYMBOL(dma_free_coherent);
 
diff --git a/arch/arm/mm/init.c b/arch/arm/mm/init.c
index 595079f..6e9fde6 100644
--- a/arch/arm/mm/init.c
+++ b/arch/arm/mm/init.c
@@ -20,6 +20,7 @@
 #include <linux/highmem.h>
 #include <linux/gfp.h>
 #include <linux/memblock.h>
+#include <linux/dma-contiguous.h>
 
 #include <asm/mach-types.h>
 #include <asm/memblock.h>
@@ -226,6 +227,17 @@ static void __init arm_adjust_dma_zone(unsigned long *size, unsigned long *hole,
 }
 #endif
 
+void __init setup_dma_zone(struct machine_desc *mdesc)
+{
+#ifdef CONFIG_ZONE_DMA
+	if (mdesc->dma_zone_size) {
+		arm_dma_zone_size = mdesc->dma_zone_size;
+		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
+	} else
+		arm_dma_limit = 0xffffffff;
+#endif
+}
+
 static void __init arm_bootmem_free(unsigned long min, unsigned long max_low,
 	unsigned long max_high)
 {
@@ -273,12 +285,9 @@ static void __init arm_bootmem_free(unsigned long min, unsigned long max_low,
 	 * Adjust the sizes according to any special requirements for
 	 * this machine type.
 	 */
-	if (arm_dma_zone_size) {
+	if (arm_dma_zone_size)
 		arm_adjust_dma_zone(zone_size, zhole_size,
 			arm_dma_zone_size >> PAGE_SHIFT);
-		arm_dma_limit = PHYS_OFFSET + arm_dma_zone_size - 1;
-	} else
-		arm_dma_limit = 0xffffffff;
 #endif
 
 	free_area_init_node(0, zone_size, min, zhole_size);
@@ -364,6 +373,12 @@ void __init arm_memblock_init(struct meminfo *mi, struct machine_desc *mdesc)
 	if (mdesc->reserve)
 		mdesc->reserve();
 
+	/*
+	 * reserve memory for DMA contigouos allocations,
+	 * must come from DMA area inside low memory
+	 */
+	dma_contiguous_reserve(min(arm_dma_limit, arm_lowmem_limit));
+
 	arm_memblock_steal_permitted = false;
 	memblock_allow_resize();
 	memblock_dump_all();
diff --git a/arch/arm/mm/mm.h b/arch/arm/mm/mm.h
index 27f4a61..93dc0c1 100644
--- a/arch/arm/mm/mm.h
+++ b/arch/arm/mm/mm.h
@@ -67,5 +67,8 @@ extern u32 arm_dma_limit;
 #define arm_dma_limit ((u32)~0)
 #endif
 
+extern phys_addr_t arm_lowmem_limit;
+
 void __init bootmem_init(void);
 void arm_mm_memblock_reserve(void);
+void dma_contiguous_remap(void);
diff --git a/arch/arm/mm/mmu.c b/arch/arm/mm/mmu.c
index f77f1db..5eb9790 100644
--- a/arch/arm/mm/mmu.c
+++ b/arch/arm/mm/mmu.c
@@ -287,6 +287,11 @@ static struct mem_type mem_types[] = {
 				PMD_SECT_UNCACHED | PMD_SECT_XN,
 		.domain    = DOMAIN_KERNEL,
 	},
+	[MT_MEMORY_DMA_READY] = {
+		.prot_pte  = L_PTE_PRESENT | L_PTE_YOUNG | L_PTE_DIRTY,
+		.prot_l1   = PMD_TYPE_TABLE,
+		.domain    = DOMAIN_KERNEL,
+	},
 };
 
 const struct mem_type *get_mem_type(unsigned int type)
@@ -428,6 +433,7 @@ static void __init build_mem_type_table(void)
 	if (arch_is_coherent() && cpu_is_xsc3()) {
 		mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
 		mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
+		mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
 		mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 		mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
 	}
@@ -459,6 +465,7 @@ static void __init build_mem_type_table(void)
 			mem_types[MT_DEVICE_CACHED].prot_pte |= L_PTE_SHARED;
 			mem_types[MT_MEMORY].prot_sect |= PMD_SECT_S;
 			mem_types[MT_MEMORY].prot_pte |= L_PTE_SHARED;
+			mem_types[MT_MEMORY_DMA_READY].prot_pte |= L_PTE_SHARED;
 			mem_types[MT_MEMORY_NONCACHED].prot_sect |= PMD_SECT_S;
 			mem_types[MT_MEMORY_NONCACHED].prot_pte |= L_PTE_SHARED;
 		}
@@ -510,6 +517,7 @@ static void __init build_mem_type_table(void)
 	mem_types[MT_HIGH_VECTORS].prot_l1 |= ecc_mask;
 	mem_types[MT_MEMORY].prot_sect |= ecc_mask | cp->pmd;
 	mem_types[MT_MEMORY].prot_pte |= kern_pgprot;
+	mem_types[MT_MEMORY_DMA_READY].prot_pte |= kern_pgprot;
 	mem_types[MT_MEMORY_NONCACHED].prot_sect |= ecc_mask;
 	mem_types[MT_ROM].prot_sect |= cp->pmd;
 
@@ -594,7 +602,7 @@ static void __init alloc_init_section(pud_t *pud, unsigned long addr,
 	 * L1 entries, whereas PGDs refer to a group of L1 entries making
 	 * up one logical pointer to an L2 table.
 	 */
-	if (((addr | end | phys) & ~SECTION_MASK) == 0) {
+	if (type->prot_sect && ((addr | end | phys) & ~SECTION_MASK) == 0) {
 		pmd_t *p = pmd;
 
 #ifndef CONFIG_ARM_LPAE
@@ -812,7 +820,7 @@ static int __init early_vmalloc(char *arg)
 }
 early_param("vmalloc", early_vmalloc);
 
-static phys_addr_t lowmem_limit __initdata = 0;
+phys_addr_t arm_lowmem_limit __initdata = 0;
 
 void __init sanity_check_meminfo(void)
 {
@@ -895,8 +903,8 @@ void __init sanity_check_meminfo(void)
 			bank->size = newsize;
 		}
 #endif
-		if (!bank->highmem && bank->start + bank->size > lowmem_limit)
-			lowmem_limit = bank->start + bank->size;
+		if (!bank->highmem && bank->start + bank->size > arm_lowmem_limit)
+			arm_lowmem_limit = bank->start + bank->size;
 
 		j++;
 	}
@@ -921,8 +929,8 @@ void __init sanity_check_meminfo(void)
 	}
 #endif
 	meminfo.nr_banks = j;
-	high_memory = __va(lowmem_limit - 1) + 1;
-	memblock_set_current_limit(lowmem_limit);
+	high_memory = __va(arm_lowmem_limit - 1) + 1;
+	memblock_set_current_limit(arm_lowmem_limit);
 }
 
 static inline void prepare_page_table(void)
@@ -947,8 +955,8 @@ static inline void prepare_page_table(void)
 	 * Find the end of the first block of lowmem.
 	 */
 	end = memblock.memory.regions[0].base + memblock.memory.regions[0].size;
-	if (end >= lowmem_limit)
-		end = lowmem_limit;
+	if (end >= arm_lowmem_limit)
+		end = arm_lowmem_limit;
 
 	/*
 	 * Clear out all the kernel space mappings, except for the first
@@ -1091,8 +1099,8 @@ static void __init map_lowmem(void)
 		phys_addr_t end = start + reg->size;
 		struct map_desc map;
 
-		if (end > lowmem_limit)
-			end = lowmem_limit;
+		if (end > arm_lowmem_limit)
+			end = arm_lowmem_limit;
 		if (start >= end)
 			break;
 
@@ -1113,11 +1121,12 @@ void __init paging_init(struct machine_desc *mdesc)
 {
 	void *zero_page;
 
-	memblock_set_current_limit(lowmem_limit);
+	memblock_set_current_limit(arm_lowmem_limit);
 
 	build_mem_type_table();
 	prepare_page_table();
 	map_lowmem();
+	dma_contiguous_remap();
 	devicemaps_init(mdesc);
 	kmap_init();
 
-- 
1.7.1.569.g6f426

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[PATCHv23 16/16] ARM: Samsung: use CMA for 2 memory banks for s5p-mfc device

[Marek Szyprowski]

Replace custom memory bank initialization using memblock_reserve and
dma_declare_coherent with a single call to CMA's dma_declare_contiguous.

Signed-off-by: Marek Szyprowski <m.szyprowski@samsung.com>
Signed-off-by: Kyungmin Park <kyungmin.park@samsung.com>
Acked-by: Arnd Bergmann <arnd@arndb.de>
---
 arch/arm/plat-s5p/dev-mfc.c |   51 ++++++-------------------------------------
 1 files changed, 7 insertions(+), 44 deletions(-)

diff --git a/arch/arm/plat-s5p/dev-mfc.c b/arch/arm/plat-s5p/dev-mfc.c
index a30d36b..fcb8400 100644
--- a/arch/arm/plat-s5p/dev-mfc.c
+++ b/arch/arm/plat-s5p/dev-mfc.c
@@ -14,6 +14,7 @@
 #include <linux/interrupt.h>
 #include <linux/platform_device.h>
 #include <linux/dma-mapping.h>
+#include <linux/dma-contiguous.h>
 #include <linux/memblock.h>
 #include <linux/ioport.h>
 
@@ -22,52 +23,14 @@
 #include <plat/irqs.h>
 #include <plat/mfc.h>
 
-struct s5p_mfc_reserved_mem {
-	phys_addr_t	base;
-	unsigned long	size;
-	struct device	*dev;
-};
-
-static struct s5p_mfc_reserved_mem s5p_mfc_mem[2] __initdata;
-
 void __init s5p_mfc_reserve_mem(phys_addr_t rbase, unsigned int rsize,
 				phys_addr_t lbase, unsigned int lsize)
 {
-	int i;
-
-	s5p_mfc_mem[0].dev = &s5p_device_mfc_r.dev;
-	s5p_mfc_mem[0].base = rbase;
-	s5p_mfc_mem[0].size = rsize;
-
-	s5p_mfc_mem[1].dev = &s5p_device_mfc_l.dev;
-	s5p_mfc_mem[1].base = lbase;
-	s5p_mfc_mem[1].size = lsize;
-
-	for (i = 0; i < ARRAY_SIZE(s5p_mfc_mem); i++) {
-		struct s5p_mfc_reserved_mem *area = &s5p_mfc_mem[i];
-		if (memblock_remove(area->base, area->size)) {
-			printk(KERN_ERR "Failed to reserve memory for MFC device (%ld bytes at 0x%08lx)\n",
-			       area->size, (unsigned long) area->base);
-			area->base = 0;
-		}
-	}
-}
-
-static int __init s5p_mfc_memory_init(void)
-{
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(s5p_mfc_mem); i++) {
-		struct s5p_mfc_reserved_mem *area = &s5p_mfc_mem[i];
-		if (!area->base)
-			continue;
+	if (dma_declare_contiguous(&s5p_device_mfc_r.dev, rsize, rbase, 0))
+		printk(KERN_ERR "Failed to reserve memory for MFC device (%u bytes at 0x%08lx)\n",
+		       rsize, (unsigned long) rbase);
 
-		if (dma_declare_coherent_memory(area->dev, area->base,
-				area->base, area->size,
-				DMA_MEMORY_MAP | DMA_MEMORY_EXCLUSIVE) == 0)
-			printk(KERN_ERR "Failed to declare coherent memory for MFC device (%ld bytes at 0x%08lx)\n",
-			       area->size, (unsigned long) area->base);
-	}
-	return 0;
+	if (dma_declare_contiguous(&s5p_device_mfc_l.dev, lsize, lbase, 0))
+		printk(KERN_ERR "Failed to reserve memory for MFC device (%u bytes at 0x%08lx)\n",
+		       rsize, (unsigned long) rbase);
 }
-device_initcall(s5p_mfc_memory_init);
-- 
1.7.1.569.g6f426

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Re: [Linaro-mm-sig] [PATCHv23 00/16] Contiguous Memory Allocator

[Barry Song]

2012/2/23 Marek Szyprowski <m.szyprowski@samsung.com>:
> Hi,
>
> This is (yet another) quick update of CMA patches. I've rebased them
> onto next-20120222 tree from
> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git and
> fixed the bug pointed by Aaro Koskinen.

For the whole series:

Tested-by: Barry Song <Baohua.Song@csr.com>

and i also write a simple kernel helper to test the CMA:

/*
 * kernek module helper for testing CMA
 *
 * Copyright (c) 2011 Cambridge Silicon Radio Limited, a CSR plc group company.
 *
 * Licensed under GPLv2 or later.
 */

#include <linux/module.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/dma-mapping.h>

#define CMA_NUM  10
static struct device *cma_dev;
static dma_addr_t dma_phys[CMA_NUM];
static void *dma_virt[CMA_NUM];

/* any read request will free coherent memory, eg.
 * cat /dev/cma_test
 */
static ssize_t
cma_test_read(struct file *file, char __user *buf, size_t count, loff_t *ppos)
{
	int i;

	for (i = 0; i < CMA_NUM; i++) {
		if (dma_virt[i]) {
			dma_free_coherent(cma_dev, (i + 1) * SZ_1M, dma_virt[i], dma_phys[i]);
			_dev_info(cma_dev, "free virt: %p phys: %p\n", dma_virt[i], (void
*)dma_phys[i]);
			dma_virt[i] = NULL;
			break;
		}
	}
	return 0;
}

/*
 * any write request will alloc coherent memory, eg.
 * echo 0 > /dev/cma_test
 */
static ssize_t
cma_test_write(struct file *file, const char __user *buf, size_t
count, loff_t *ppos)
{
	int i;
	int ret;

	for (i = 0; i < CMA_NUM; i++) {
		if (!dma_virt[i]) {
			dma_virt[i] = dma_alloc_coherent(cma_dev, (i + 1) * SZ_1M,
&dma_phys[i], GFP_KERNEL);

			if (dma_virt[i])
				_dev_info(cma_dev, "alloc virt: %p phys: %p\n", dma_virt[i], (void
*)dma_phys[i]);
			else {
				dev_err(cma_dev, "no mem in CMA area\n");
				ret = -ENOMEM;
			}
			break;
		}
	}

	return count;
}

static const struct file_operations cma_test_fops = {
	.owner =    THIS_MODULE,
	.read  =    cma_test_read,
	.write =    cma_test_write,
};

static struct miscdevice cma_test_misc = {
	.name = "cma_test",
	.fops = &cma_test_fops,
};

static int __init cma_test_init(void)
{
	int ret = 0;

	ret = misc_register(&cma_test_misc);
	if (unlikely(ret)) {
		pr_err("failed to register cma test misc device!\n");
		return ret;
	}
	cma_dev = cma_test_misc.this_device;
	cma_dev->coherent_dma_mask = ~0;
	_dev_info(cma_dev, "registered.\n");

	return ret;
}
module_init(cma_test_init);

static void __exit cma_test_exit(void)
{
	misc_deregister(&cma_test_misc);
}
module_exit(cma_test_exit);

MODULE_LICENSE("GPL");
MODULE_AUTHOR("Barry Song <Baohua.Song@csr.com>");
MODULE_DESCRIPTION("kernel module to help the test of CMA");
MODULE_ALIAS("CMA test");

While fulfilling "dd if=/dev/mmcblk0 of=/dev/null bs=4096
count=1024000000 &" and "dd if=/dev/zero of=/data/1 bs=4096
count=1024000000 &" to exhaust memory at background,
i alloc the contiguous memories using the cma_test driver:
$echo 0 > /dev/cma_test
[   16.582216] misc cma_test: alloc virt: ceb00000 phys: 0eb00000
$echo 0 > /dev/cma_test
[   20.843395] misc cma_test: alloc virt: cec00000 phys: 0ec00000
$echo 0 > /dev/cma_test
[   21.774601] misc cma_test: alloc virt: cee00000 phys: 0ee00000
$echo 0 > /dev/cma_test
[   22.925633] misc cma_test: alloc virt: cf100000 phys: 0f100000

i did see the page write back is executed and contiguous memories are
always available.

P.S. the whole series was also back ported to 2.6.38.8 which our
release is based on.

>
> Best regards
> Marek Szyprowski
> Samsung Poland R&D Center
>
> Links to previous versions of the patchset:
> v22: <http://www.spinics.net/lists/linux-media/msg44370.html>
> v21: <http://www.spinics.net/lists/linux-media/msg44155.html>
> v20: <http://www.spinics.net/lists/linux-mm/msg29145.html>
> v19: <http://www.spinics.net/lists/linux-mm/msg29145.html>
> v18: <http://www.spinics.net/lists/linux-mm/msg28125.html>
> v17: <http://www.spinics.net/lists/arm-kernel/msg148499.html>
> v16: <http://www.spinics.net/lists/linux-mm/msg25066.html>
> v15: <http://www.spinics.net/lists/linux-mm/msg23365.html>
> v14: <http://www.spinics.net/lists/linux-media/msg36536.html>
> v13: (internal, intentionally not released)
> v12: <http://www.spinics.net/lists/linux-media/msg35674.html>
> v11: <http://www.spinics.net/lists/linux-mm/msg21868.html>
> v10: <http://www.spinics.net/lists/linux-mm/msg20761.html>
>  v9: <http://article.gmane.org/gmane.linux.kernel.mm/60787>
>  v8: <http://article.gmane.org/gmane.linux.kernel.mm/56855>
>  v7: <http://article.gmane.org/gmane.linux.kernel.mm/55626>
>  v6: <http://article.gmane.org/gmane.linux.kernel.mm/55626>
>  v5: (intentionally left out as CMA v5 was identical to CMA v4)
>  v4: <http://article.gmane.org/gmane.linux.kernel.mm/52010>
>  v3: <http://article.gmane.org/gmane.linux.kernel.mm/51573>
>  v2: <http://article.gmane.org/gmane.linux.kernel.mm/50986>
>  v1: <http://article.gmane.org/gmane.linux.kernel.mm/50669>
>
>
> Changelog:
>
> v23:
>    1. fixed bug spotted by Aaro Koskinen (incorrect check inside VM_BUG_ON)
>
>    2. rebased onto next-20120222 tree from
>       git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git
>
> v22:
>    1. Fixed compilation break caused by missing fixup patch in v21
>
>    2. Fixed typos in the comments
>
>    3. Removed superfluous #include entries
>
> v21:
>    1. Fixed incorrect check which broke memory compaction code
>
>    2. Fixed hacky and racy min_free_kbytes handling
>
>    3. Added serialization patch to watermark calculation
>
>    4. Fixed typos here and there in the comments
>
> v20 and earlier - see previous patchsets.
>
>
> Patches in this patchset:
>
> Marek Szyprowski (6):
>  mm: extract reclaim code from __alloc_pages_direct_reclaim()
>  mm: trigger page reclaim in alloc_contig_range() to stabilise
>    watermarks
>  drivers: add Contiguous Memory Allocator
>  X86: integrate CMA with DMA-mapping subsystem
>  ARM: integrate CMA with DMA-mapping subsystem
>  ARM: Samsung: use CMA for 2 memory banks for s5p-mfc device
>
> Mel Gorman (1):
>  mm: Serialize access to min_free_kbytes
>
> Michal Nazarewicz (9):
>  mm: page_alloc: remove trailing whitespace
>  mm: compaction: introduce isolate_migratepages_range()
>  mm: compaction: introduce map_pages()
>  mm: compaction: introduce isolate_freepages_range()
>  mm: compaction: export some of the functions
>  mm: page_alloc: introduce alloc_contig_range()
>  mm: page_alloc: change fallbacks array handling
>  mm: mmzone: MIGRATE_CMA migration type added
>  mm: page_isolation: MIGRATE_CMA isolation functions added
>
>  Documentation/kernel-parameters.txt   |    9 +
>  arch/Kconfig                          |    3 +
>  arch/arm/Kconfig                      |    2 +
>  arch/arm/include/asm/dma-contiguous.h |   15 ++
>  arch/arm/include/asm/mach/map.h       |    1 +
>  arch/arm/kernel/setup.c               |    9 +-
>  arch/arm/mm/dma-mapping.c             |  369 ++++++++++++++++++++++++------
>  arch/arm/mm/init.c                    |   23 ++-
>  arch/arm/mm/mm.h                      |    3 +
>  arch/arm/mm/mmu.c                     |   31 ++-
>  arch/arm/plat-s5p/dev-mfc.c           |   51 +----
>  arch/x86/Kconfig                      |    1 +
>  arch/x86/include/asm/dma-contiguous.h |   13 +
>  arch/x86/include/asm/dma-mapping.h    |    4 +
>  arch/x86/kernel/pci-dma.c             |   18 ++-
>  arch/x86/kernel/pci-nommu.c           |    8 +-
>  arch/x86/kernel/setup.c               |    2 +
>  drivers/base/Kconfig                  |   89 +++++++
>  drivers/base/Makefile                 |    1 +
>  drivers/base/dma-contiguous.c         |  401 +++++++++++++++++++++++++++++++
>  include/asm-generic/dma-contiguous.h  |   28 +++
>  include/linux/device.h                |    4 +
>  include/linux/dma-contiguous.h        |  110 +++++++++
>  include/linux/gfp.h                   |   12 +
>  include/linux/mmzone.h                |   47 +++-
>  include/linux/page-isolation.h        |   18 +-
>  mm/Kconfig                            |    2 +-
>  mm/Makefile                           |    3 +-
>  mm/compaction.c                       |  418 +++++++++++++++++++++------------
>  mm/internal.h                         |   33 +++
>  mm/memory-failure.c                   |    2 +-
>  mm/memory_hotplug.c                   |    6 +-
>  mm/page_alloc.c                       |  409 ++++++++++++++++++++++++++++----
>  mm/page_isolation.c                   |   15 +-
>  mm/vmstat.c                           |    3 +
>  35 files changed, 1790 insertions(+), 373 deletions(-)
>  create mode 100644 arch/arm/include/asm/dma-contiguous.h
>  create mode 100644 arch/x86/include/asm/dma-contiguous.h
>  create mode 100644 drivers/base/dma-contiguous.c
>  create mode 100644 include/asm-generic/dma-contiguous.h
>  create mode 100644 include/linux/dma-contiguous.h
>
> --
> 1.7.1.569.g6f426

Thanks
barry

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Re: [Linaro-mm-sig] [PATCHv23 00/16] Contiguous Memory Allocator

[Michal Nazarewicz]

On Wed, 29 Feb 2012 10:35:42 +0100, Barry Song <21cnbao@gmail.com> wrote:

> 2012/2/23 Marek Szyprowski <m.szyprowski@samsung.com>:
>> This is (yet another) quick update of CMA patches. I've rebased them
>> onto next-20120222 tree from
>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git and
>> fixed the bug pointed by Aaro Koskinen.
>
> For the whole series:
>
> Tested-by: Barry Song <Baohua.Song@csr.com>
>
> and i also write a simple kernel helper to test the CMA:

Would it make sense to make a patch out of it putting it to tools/cma (or similar)?

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

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Re: [Linaro-mm-sig] [PATCHv23 00/16] Contiguous Memory Allocator

[Barry Song]

Michal,

2012/2/29 Michal Nazarewicz <mina86@mina86.com>:
> On Wed, 29 Feb 2012 10:35:42 +0100, Barry Song <21cnbao@gmail.com> wrote:
>
>> 2012/2/23 Marek Szyprowski <m.szyprowski@samsung.com>:
>>
>>> This is (yet another) quick update of CMA patches. I've rebased them
>>> onto next-20120222 tree from
>>> git://git.kernel.org/pub/scm/linux/kernel/git/next/linux-next.git and
>>> fixed the bug pointed by Aaro Koskinen.
>>
>>
>> For the whole series:
>>
>> Tested-by: Barry Song <Baohua.Song@csr.com>
>>
>> and i also write a simple kernel helper to test the CMA:
>
>
> Would it make sense to make a patch out of it putting it to tools/cma (or
> similar)?

i can send a patch for this. i am just thinking, should it be placed
in tools/ as a test utility or Documents/ as an example to explain CMA
to users who want to use cma. i also think we should have a seperate
document to explain cma in details in documents/, and my helper
program can be placed there.

how do you think?
>
> --
> Best regards,                                         _     _
> .o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
> ..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
> ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

thanks
barry

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Re: [Linaro-mm-sig] [PATCHv23 00/16] Contiguous Memory Allocator

[Michal Nazarewicz]

On Wed, 29 Feb 2012 14:34:02 +0100, Barry Song <21cnbao@gmail.com> wrote:

> 2012/2/29 Michal Nazarewicz <mina86@mina86.com>:
>> On Wed, 29 Feb 2012 10:35:42 +0100, Barry Song <21cnbao@gmail.com> wrote:
>>> and i also write a simple kernel helper to test the CMA:

>> Would it make sense to make a patch out of it putting it to tools/cma (or
>> similar)?

> i can send a patch for this. i am just thinking, should it be placed
> in tools/ as a test utility or Documents/ as an example to explain CMA
> to users who want to use cma.

I'd put it in tools/.

> i also think we should have a seperate document to explain cma in details
> in documents/, and my helper program can be placed there.

I'm currently writing an article for LWN which I hope will also lead to something
worth putting in Documentation/.

-- 
Best regards,                                         _     _
.o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

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Re: [Linaro-mm-sig] [PATCHv23 00/16] Contiguous Memory Allocator

[Barry Song]

2012/2/29 Michal Nazarewicz <mina86@mina86.com>:
> On Wed, 29 Feb 2012 14:34:02 +0100, Barry Song <21cnbao@gmail.com> wrote:
>
>> 2012/2/29 Michal Nazarewicz <mina86@mina86.com>:
>>>
>>> On Wed, 29 Feb 2012 10:35:42 +0100, Barry Song <21cnbao@gmail.com> wrote:
>>>>
>>>> and i also write a simple kernel helper to test the CMA:
>
>
>>> Would it make sense to make a patch out of it putting it to tools/cma (or
>>> similar)?
>
>
>> i can send a patch for this. i am just thinking, should it be placed
>> in tools/ as a test utility or Documents/ as an example to explain CMA
>> to users who want to use cma.
>
>
> I'd put it in tools/.

ok. i will handle this.

>
>
>> i also think we should have a seperate document to explain cma in details
>> in documents/, and my helper program can be placed there.
>
>
> I'm currently writing an article for LWN which I hope will also lead to
> something
> worth putting in Documentation/.
>

fine.

>
> --
> Best regards,                                         _     _
> .o. | Liege of Serenely Enlightened Majesty of      o' \,=./ `o
> ..o | Computer Science,  Michał “mina86” Nazarewicz    (o o)
> ooo +----<email/xmpp: mpn@google.com>--------------ooO--(_)--Ooo--

-barry

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