* + mm-compaction-add-support-for-0-order-folio-memory-compaction.patch added to mm-unstable branch
@ 2024-02-20 19:44 Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2024-02-20 19:44 UTC (permalink / raw)
To: mm-commits, yuzhao, ying.huang, willy, vishal.moola, vbabka,
shikemeng, ryan.roberts, mgorman, mcgrof, kirill.shutemov, hannes,
fengwei.yin, david, baolin.wang, a.manzanares, ziy, akpm
The patch titled
Subject: mm/compaction: add support for >0 order folio memory compaction.
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/compaction: add support for >0 order folio memory compaction.
Date: Tue, 20 Feb 2024 13:32:19 -0500
Before last commit, memory compaction only migrates order-0 folios and
skips >0 order folios. Last commit splits all >0 order folios during
compaction. This commit migrates >0 order folios during compaction by
keeping isolated free pages at their original size without splitting them
into order-0 pages and using them directly during migration process.
What is different from the prior implementation:
1. All isolated free pages are kept in a NR_PAGE_ORDERS array of page
lists, where each page list stores free pages in the same order.
2. All free pages are not post_alloc_hook() processed nor buddy pages,
although their orders are stored in first page's private like buddy
pages.
3. During migration, in new page allocation time (i.e., in
compaction_alloc()), free pages are then processed by post_alloc_hook().
When migration fails and a new page is returned (i.e., in
compaction_free()), free pages are restored by reversing the
post_alloc_hook() operations using newly added
free_pages_prepare_fpi_none().
Step 3 is done for a latter optimization that splitting and/or merging
free pages during compaction becomes easier.
Note: without splitting free pages, compaction can end prematurely due to
migration will return -ENOMEM even if there is free pages. This happens
when no order-0 free page exist and compaction_alloc() return NULL.
Link: https://lkml.kernel.org/r/20240220183220.1451315-4-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/compaction.c | 140 +++++++++++++++++++++++++---------------------
mm/internal.h | 4 -
mm/page_alloc.c | 2
3 files changed, 83 insertions(+), 63 deletions(-)
--- a/mm/compaction.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/compaction.c
@@ -79,45 +79,56 @@ static inline bool is_via_compact_memory
#define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT)
#endif
-static unsigned long release_freepages(struct list_head *freelist)
+static void split_map_pages(struct list_head *freepages)
{
+ unsigned int i, order;
struct page *page, *next;
- unsigned long high_pfn = 0;
+ LIST_HEAD(tmp_list);
- list_for_each_entry_safe(page, next, freelist, lru) {
- unsigned long pfn = page_to_pfn(page);
- list_del(&page->lru);
- __free_page(page);
- if (pfn > high_pfn)
- high_pfn = pfn;
- }
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned int nr_pages;
- return high_pfn;
+ list_del(&page->lru);
+
+ nr_pages = 1 << order;
+
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ if (order)
+ split_page(page, order);
+
+ for (i = 0; i < nr_pages; i++) {
+ list_add(&page->lru, &tmp_list);
+ page++;
+ }
+ }
+ list_splice_init(&tmp_list, &freepages[0]);
+ }
}
-static void split_map_pages(struct list_head *list)
+static unsigned long release_free_list(struct list_head *freepages)
{
- unsigned int i, order, nr_pages;
- struct page *page, *next;
- LIST_HEAD(tmp_list);
-
- list_for_each_entry_safe(page, next, list, lru) {
- list_del(&page->lru);
+ int order;
+ unsigned long high_pfn = 0;
- order = page_private(page);
- nr_pages = 1 << order;
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ struct page *page, *next;
- post_alloc_hook(page, order, __GFP_MOVABLE);
- if (order)
- split_page(page, order);
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned long pfn = page_to_pfn(page);
- for (i = 0; i < nr_pages; i++) {
- list_add(&page->lru, &tmp_list);
- page++;
+ list_del(&page->lru);
+ /*
+ * Convert free pages into post allocation pages, so
+ * that we can free them via __free_page.
+ */
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ __free_pages(page, order);
+ if (pfn > high_pfn)
+ high_pfn = pfn;
}
}
-
- list_splice(&tmp_list, list);
+ return high_pfn;
}
#ifdef CONFIG_COMPACTION
@@ -670,7 +681,7 @@ static unsigned long isolate_freepages_b
nr_scanned += isolated - 1;
total_isolated += isolated;
cc->nr_freepages += isolated;
- list_add_tail(&page->lru, freelist);
+ list_add_tail(&page->lru, &freelist[order]);
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
@@ -735,7 +746,11 @@ isolate_freepages_range(struct compact_c
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
- LIST_HEAD(freelist);
+ int order;
+ struct list_head tmp_freepages[NR_PAGE_ORDERS];
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&tmp_freepages[order]);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
@@ -766,7 +781,7 @@ isolate_freepages_range(struct compact_c
break;
isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, &freelist, 0, true);
+ block_end_pfn, tmp_freepages, 0, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
@@ -783,15 +798,15 @@ isolate_freepages_range(struct compact_c
*/
}
- /* __isolate_free_page() does not map the pages */
- split_map_pages(&freelist);
-
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
- release_freepages(&freelist);
+ release_free_list(tmp_freepages);
return 0;
}
+ /* __isolate_free_page() does not map the pages */
+ split_map_pages(tmp_freepages);
+
/* We don't use freelists for anything. */
return pfn;
}
@@ -1518,7 +1533,7 @@ fast_isolate_around(struct compact_contr
if (!page)
return;
- isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
+ isolate_freepages_block(cc, &start_pfn, end_pfn, cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
if (start_pfn == end_pfn && !cc->no_set_skip_hint)
@@ -1647,7 +1662,7 @@ static void fast_isolate_freepages(struc
nr_scanned += nr_isolated - 1;
total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
- list_add_tail(&page->lru, &cc->freepages);
+ list_add_tail(&page->lru, &cc->freepages[order]);
count_compact_events(COMPACTISOLATED, nr_isolated);
} else {
/* If isolation fails, abort the search */
@@ -1724,13 +1739,12 @@ static void isolate_freepages(struct com
unsigned long isolate_start_pfn; /* exact pfn we start at */
unsigned long block_end_pfn; /* end of current pageblock */
unsigned long low_pfn; /* lowest pfn scanner is able to scan */
- struct list_head *freelist = &cc->freepages;
unsigned int stride;
/* Try a small search of the free lists for a candidate */
fast_isolate_freepages(cc);
if (cc->nr_freepages)
- goto splitmap;
+ return;
/*
* Initialise the free scanner. The starting point is where we last
@@ -1790,7 +1804,7 @@ static void isolate_freepages(struct com
/* Found a block suitable for isolating free pages from. */
nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, stride, false);
+ block_end_pfn, cc->freepages, stride, false);
/* Update the skip hint if the full pageblock was scanned */
if (isolate_start_pfn == block_end_pfn)
@@ -1831,10 +1845,6 @@ static void isolate_freepages(struct com
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
-
-splitmap:
- /* __isolate_free_page() does not map the pages */
- split_map_pages(freelist);
}
/*
@@ -1845,24 +1855,22 @@ static struct folio *compaction_alloc(st
{
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ int order = folio_order(src);
- /* this makes migrate_pages() split the source page and retry */
- if (folio_test_large(src))
- return NULL;
-
- if (list_empty(&cc->freepages)) {
+ if (list_empty(&cc->freepages[order])) {
isolate_freepages(cc);
-
- if (list_empty(&cc->freepages))
+ if (list_empty(&cc->freepages[order]))
return NULL;
}
- dst = list_entry(cc->freepages.next, struct folio, lru);
+ dst = list_first_entry(&cc->freepages[order], struct folio, lru);
list_del(&dst->lru);
- cc->nr_freepages--;
- cc->nr_migratepages--;
-
- return dst;
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+ if (order)
+ prep_compound_page(&dst->page, order);
+ cc->nr_freepages -= 1 << order;
+ cc->nr_migratepages -= 1 << order;
+ return page_rmappable_folio(&dst->page);
}
/*
@@ -1873,10 +1881,19 @@ static struct folio *compaction_alloc(st
static void compaction_free(struct folio *dst, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
+ int order = folio_order(dst);
+ struct page *page = &dst->page;
- list_add(&dst->lru, &cc->freepages);
- cc->nr_freepages++;
- cc->nr_migratepages++;
+ if (folio_put_testzero(dst)) {
+ free_pages_prepare(page, order);
+ list_add(&dst->lru, &cc->freepages[order]);
+ cc->nr_freepages += 1 << order;
+ }
+ cc->nr_migratepages += 1 << order;
+ /*
+ * someone else has referenced the page, we cannot take it back to our
+ * free list.
+ */
}
/* possible outcome of isolate_migratepages */
@@ -2489,6 +2506,7 @@ compact_zone(struct compact_control *cc,
const bool sync = cc->mode != MIGRATE_ASYNC;
bool update_cached;
unsigned int nr_succeeded = 0, nr_migratepages;
+ int order;
/*
* These counters track activities during zone compaction. Initialize
@@ -2498,7 +2516,8 @@ compact_zone(struct compact_control *cc,
cc->total_free_scanned = 0;
cc->nr_migratepages = 0;
cc->nr_freepages = 0;
- INIT_LIST_HEAD(&cc->freepages);
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&cc->freepages[order]);
INIT_LIST_HEAD(&cc->migratepages);
cc->migratetype = gfp_migratetype(cc->gfp_mask);
@@ -2690,7 +2709,7 @@ out:
* so we don't leave any returned pages behind in the next attempt.
*/
if (cc->nr_freepages > 0) {
- unsigned long free_pfn = release_freepages(&cc->freepages);
+ unsigned long free_pfn = release_free_list(cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
@@ -2709,7 +2728,6 @@ out:
trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
- VM_BUG_ON(!list_empty(&cc->freepages));
VM_BUG_ON(!list_empty(&cc->migratepages));
return ret;
--- a/mm/internal.h~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/internal.h
@@ -447,6 +447,8 @@ extern void prep_compound_page(struct pa
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
+extern bool free_pages_prepare(struct page *page, unsigned int order);
+
extern int user_min_free_kbytes;
extern void free_unref_page(struct page *page, unsigned int order);
@@ -481,7 +483,7 @@ int split_free_page(struct page *free_pa
* completes when free_pfn <= migrate_pfn
*/
struct compact_control {
- struct list_head freepages; /* List of free pages to migrate to */
+ struct list_head freepages[NR_PAGE_ORDERS]; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
unsigned int nr_freepages; /* Number of isolated free pages */
unsigned int nr_migratepages; /* Number of pages to migrate */
--- a/mm/page_alloc.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/page_alloc.c
@@ -1080,7 +1080,7 @@ static void kernel_init_pages(struct pag
kasan_enable_current();
}
-static __always_inline bool free_pages_prepare(struct page *page,
+__always_inline bool free_pages_prepare(struct page *page,
unsigned int order)
{
int bad = 0;
_
Patches currently in -mm which might be from ziy@nvidia.com are
mm-page_alloc-remove-unused-fpi_flags-in-free_pages_prepare.patch
mm-compaction-enable-compacting-0-order-folios.patch
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
mm-compaction-optimize-0-order-folio-compaction-with-free-page-split.patch
^ permalink raw reply [flat|nested] 4+ messages in thread* + mm-compaction-add-support-for-0-order-folio-memory-compaction.patch added to mm-unstable branch
@ 2024-02-20 2:08 Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2024-02-20 2:08 UTC (permalink / raw)
To: mm-commits, yuzhao, ying.huang, willy, vishal.moola, vbabka,
shikemeng, ryan.roberts, mgorman, mcgrof, kirill.shutemov, hannes,
fengwei.yin, david, baolin.wang, a.manzanares, ziy, akpm
The patch titled
Subject: mm/compaction: add support for >0 order folio memory compaction
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/compaction: add support for >0 order folio memory compaction
Date: Fri, 16 Feb 2024 12:04:31 -0500
Before last commit, memory compaction only migrates order-0 folios and
skips >0 order folios. Last commit splits all >0 order folios during
compaction. This commit migrates >0 order folios during compaction by
keeping isolated free pages at their original size without splitting them
into order-0 pages and using them directly during migration process.
What is different from the prior implementation:
1. All isolated free pages are kept in a NR_PAGE_ORDERS array of page
lists, where each page list stores free pages in the same order.
2. All free pages are not post_alloc_hook() processed nor buddy pages,
although their orders are stored in first page's private like buddy
pages.
3. During migration, in new page allocation time (i.e., in
compaction_alloc()), free pages are then processed by post_alloc_hook().
When migration fails and a new page is returned (i.e., in
compaction_free()), free pages are restored by reversing the
post_alloc_hook() operations using newly added
free_pages_prepare_fpi_none().
Step 3 is done for a latter optimization that splitting and/or merging
free pages during compaction becomes easier.
Note: without splitting free pages, compaction can end prematurely due to
migration will return -ENOMEM even if there is free pages. This happens
when no order-0 free page exist and compaction_alloc() return NULL.
Link: https://lkml.kernel.org/r/20240216170432.1268753-4-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Reviewed-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Reviewed-by: Vlastimil Babka <vbabka@suse.cz>
Tested-by: Baolin Wang <baolin.wang@linux.alibaba.com>
Tested-by: Yu Zhao <yuzhao@google.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/compaction.c | 140 +++++++++++++++++++++++++---------------------
mm/internal.h | 4 -
mm/page_alloc.c | 2
3 files changed, 83 insertions(+), 63 deletions(-)
--- a/mm/compaction.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/compaction.c
@@ -66,45 +66,56 @@ static inline void count_compact_events(
#define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT)
#endif
-static unsigned long release_freepages(struct list_head *freelist)
+static void split_map_pages(struct list_head *freepages)
{
+ unsigned int i, order;
struct page *page, *next;
- unsigned long high_pfn = 0;
+ LIST_HEAD(tmp_list);
- list_for_each_entry_safe(page, next, freelist, lru) {
- unsigned long pfn = page_to_pfn(page);
- list_del(&page->lru);
- __free_page(page);
- if (pfn > high_pfn)
- high_pfn = pfn;
- }
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned int nr_pages;
- return high_pfn;
+ list_del(&page->lru);
+
+ nr_pages = 1 << order;
+
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ if (order)
+ split_page(page, order);
+
+ for (i = 0; i < nr_pages; i++) {
+ list_add(&page->lru, &tmp_list);
+ page++;
+ }
+ }
+ list_splice_init(&tmp_list, &freepages[0]);
+ }
}
-static void split_map_pages(struct list_head *list)
+static unsigned long release_free_list(struct list_head *freepages)
{
- unsigned int i, order, nr_pages;
- struct page *page, *next;
- LIST_HEAD(tmp_list);
-
- list_for_each_entry_safe(page, next, list, lru) {
- list_del(&page->lru);
+ int order;
+ unsigned long high_pfn = 0;
- order = page_private(page);
- nr_pages = 1 << order;
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ struct page *page, *next;
- post_alloc_hook(page, order, __GFP_MOVABLE);
- if (order)
- split_page(page, order);
+ list_for_each_entry_safe(page, next, &freepages[order], lru) {
+ unsigned long pfn = page_to_pfn(page);
- for (i = 0; i < nr_pages; i++) {
- list_add(&page->lru, &tmp_list);
- page++;
+ list_del(&page->lru);
+ /*
+ * Convert free pages into post allocation pages, so
+ * that we can free them via __free_page.
+ */
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ __free_pages(page, order);
+ if (pfn > high_pfn)
+ high_pfn = pfn;
}
}
-
- list_splice(&tmp_list, list);
+ return high_pfn;
}
#ifdef CONFIG_COMPACTION
@@ -657,7 +668,7 @@ static unsigned long isolate_freepages_b
nr_scanned += isolated - 1;
total_isolated += isolated;
cc->nr_freepages += isolated;
- list_add_tail(&page->lru, freelist);
+ list_add_tail(&page->lru, &freelist[order]);
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
@@ -722,7 +733,11 @@ isolate_freepages_range(struct compact_c
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
- LIST_HEAD(freelist);
+ int order;
+ struct list_head tmp_freepages[NR_PAGE_ORDERS];
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&tmp_freepages[order]);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
@@ -753,7 +768,7 @@ isolate_freepages_range(struct compact_c
break;
isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, &freelist, 0, true);
+ block_end_pfn, tmp_freepages, 0, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
@@ -770,15 +785,15 @@ isolate_freepages_range(struct compact_c
*/
}
- /* __isolate_free_page() does not map the pages */
- split_map_pages(&freelist);
-
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
- release_freepages(&freelist);
+ release_free_list(tmp_freepages);
return 0;
}
+ /* __isolate_free_page() does not map the pages */
+ split_map_pages(tmp_freepages);
+
/* We don't use freelists for anything. */
return pfn;
}
@@ -1494,7 +1509,7 @@ fast_isolate_around(struct compact_contr
if (!page)
return;
- isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
+ isolate_freepages_block(cc, &start_pfn, end_pfn, cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
if (start_pfn == end_pfn && !cc->no_set_skip_hint)
@@ -1623,7 +1638,7 @@ static void fast_isolate_freepages(struc
nr_scanned += nr_isolated - 1;
total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
- list_add_tail(&page->lru, &cc->freepages);
+ list_add_tail(&page->lru, &cc->freepages[order]);
count_compact_events(COMPACTISOLATED, nr_isolated);
} else {
/* If isolation fails, abort the search */
@@ -1700,13 +1715,12 @@ static void isolate_freepages(struct com
unsigned long isolate_start_pfn; /* exact pfn we start at */
unsigned long block_end_pfn; /* end of current pageblock */
unsigned long low_pfn; /* lowest pfn scanner is able to scan */
- struct list_head *freelist = &cc->freepages;
unsigned int stride;
/* Try a small search of the free lists for a candidate */
fast_isolate_freepages(cc);
if (cc->nr_freepages)
- goto splitmap;
+ return;
/*
* Initialise the free scanner. The starting point is where we last
@@ -1766,7 +1780,7 @@ static void isolate_freepages(struct com
/* Found a block suitable for isolating free pages from. */
nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, stride, false);
+ block_end_pfn, cc->freepages, stride, false);
/* Update the skip hint if the full pageblock was scanned */
if (isolate_start_pfn == block_end_pfn)
@@ -1807,10 +1821,6 @@ static void isolate_freepages(struct com
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
-
-splitmap:
- /* __isolate_free_page() does not map the pages */
- split_map_pages(freelist);
}
/*
@@ -1821,24 +1831,22 @@ static struct folio *compaction_alloc(st
{
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ int order = folio_order(src);
- /* this makes migrate_pages() split the source page and retry */
- if (folio_test_large(src) > 0)
- return NULL;
-
- if (list_empty(&cc->freepages)) {
+ if (list_empty(&cc->freepages[order])) {
isolate_freepages(cc);
-
- if (list_empty(&cc->freepages))
+ if (list_empty(&cc->freepages[order]))
return NULL;
}
- dst = list_entry(cc->freepages.next, struct folio, lru);
+ dst = list_first_entry(&cc->freepages[order], struct folio, lru);
list_del(&dst->lru);
- cc->nr_freepages--;
- cc->nr_migratepages -= 1 << folio_order(src);
-
- return dst;
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+ if (order)
+ prep_compound_page(&dst->page, order);
+ cc->nr_freepages -= 1 << order;
+ cc->nr_migratepages -= 1 << order;
+ return page_rmappable_folio(&dst->page);
}
/*
@@ -1849,10 +1857,19 @@ static struct folio *compaction_alloc(st
static void compaction_free(struct folio *dst, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
+ int order = folio_order(dst);
+ struct page *page = &dst->page;
- list_add(&dst->lru, &cc->freepages);
- cc->nr_freepages++;
- cc->nr_migratepages += 1 << folio_order(dst);
+ if (folio_put_testzero(dst)) {
+ free_pages_prepare(page, order);
+ list_add(&dst->lru, &cc->freepages[order]);
+ cc->nr_freepages += 1 << order;
+ }
+ cc->nr_migratepages += 1 << order;
+ /*
+ * someone else has referenced the page, we cannot take it back to our
+ * free list.
+ */
}
/* possible outcome of isolate_migratepages */
@@ -2476,6 +2493,7 @@ compact_zone(struct compact_control *cc,
const bool sync = cc->mode != MIGRATE_ASYNC;
bool update_cached;
unsigned int nr_succeeded = 0;
+ int order;
/*
* These counters track activities during zone compaction. Initialize
@@ -2485,7 +2503,8 @@ compact_zone(struct compact_control *cc,
cc->total_free_scanned = 0;
cc->nr_migratepages = 0;
cc->nr_freepages = 0;
- INIT_LIST_HEAD(&cc->freepages);
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ INIT_LIST_HEAD(&cc->freepages[order]);
INIT_LIST_HEAD(&cc->migratepages);
cc->migratetype = gfp_migratetype(cc->gfp_mask);
@@ -2671,7 +2690,7 @@ out:
* so we don't leave any returned pages behind in the next attempt.
*/
if (cc->nr_freepages > 0) {
- unsigned long free_pfn = release_freepages(&cc->freepages);
+ unsigned long free_pfn = release_free_list(cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
@@ -2690,7 +2709,6 @@ out:
trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
- VM_BUG_ON(!list_empty(&cc->freepages));
VM_BUG_ON(!list_empty(&cc->migratepages));
return ret;
--- a/mm/internal.h~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/internal.h
@@ -447,6 +447,8 @@ extern void prep_compound_page(struct pa
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
+extern bool free_pages_prepare(struct page *page, unsigned int order);
+
extern int user_min_free_kbytes;
extern void free_unref_page(struct page *page, unsigned int order);
@@ -481,7 +483,7 @@ int split_free_page(struct page *free_pa
* completes when free_pfn <= migrate_pfn
*/
struct compact_control {
- struct list_head freepages; /* List of free pages to migrate to */
+ struct list_head freepages[NR_PAGE_ORDERS]; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
unsigned int nr_freepages; /* Number of isolated free pages */
unsigned int nr_migratepages; /* Number of pages to migrate */
--- a/mm/page_alloc.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/page_alloc.c
@@ -1080,7 +1080,7 @@ static void kernel_init_pages(struct pag
kasan_enable_current();
}
-static __always_inline bool free_pages_prepare(struct page *page,
+__always_inline bool free_pages_prepare(struct page *page,
unsigned int order)
{
int bad = 0;
_
Patches currently in -mm which might be from ziy@nvidia.com are
mm-page_alloc-remove-unused-fpi_flags-in-free_pages_prepare.patch
mm-compaction-enable-compacting-0-order-folios.patch
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
mm-compaction-optimize-0-order-folio-compaction-with-free-page-split.patch
^ permalink raw reply [flat|nested] 4+ messages in thread* + mm-compaction-add-support-for-0-order-folio-memory-compaction.patch added to mm-unstable branch
@ 2024-02-04 7:20 Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2024-02-04 7:20 UTC (permalink / raw)
To: mm-commits, yuzhao, ying.huang, willy, vishal.moola, vbabka,
shikemeng, ryan.roberts, mgorman, mcgrof, kirill.shutemov, hannes,
fengwei.yin, david, baolin.wang, a.manzanares, ziy, akpm
The patch titled
Subject: mm/compaction: add support for >0 order folio memory compaction.
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
Before you just go and hit "reply", please:
a) Consider who else should be cc'ed
b) Prefer to cc a suitable mailing list as well
c) Ideally: find the original patch on the mailing list and do a
reply-to-all to that, adding suitable additional cc's
*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/compaction: add support for >0 order folio memory compaction.
Date: Fri, 2 Feb 2024 11:15:53 -0500
Before last commit, memory compaction only migrates order-0 folios and
skips >0 order folios. Last commit splits all >0 order folios during
compaction. This commit migrates >0 order folios during compaction by
keeping isolated free pages at their original size without splitting them
into order-0 pages and using them directly during migration process.
What is different from the prior implementation:
1. All isolated free pages are kept in a NR_PAGE_ORDERS array of page
lists, where each page list stores free pages in the same order.
2. All free pages are not post_alloc_hook() processed nor buddy pages,
although their orders are stored in first page's private like buddy
pages.
3. During migration, in new page allocation time (i.e., in
compaction_alloc()), free pages are then processed by post_alloc_hook().
When migration fails and a new page is returned (i.e., in
compaction_free()), free pages are restored by reversing the
post_alloc_hook() operations using newly added
free_pages_prepare_fpi_none().
Step 3 is done for a latter optimization that splitting and/or merging
free pages during compaction becomes easier.
Note: without splitting free pages, compaction can end prematurely due to
migration will return -ENOMEM even if there is free pages. This happens
when no order-0 free page exist and compaction_alloc() return NULL.
Link: https://lkml.kernel.org/r/20240202161554.565023-3-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/compaction.c | 149 +++++++++++++++++++++++++++-------------------
mm/internal.h | 9 ++
mm/page_alloc.c | 6 +
3 files changed, 104 insertions(+), 60 deletions(-)
--- a/mm/compaction.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/compaction.c
@@ -66,45 +66,67 @@ static inline void count_compact_events(
#define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT)
#endif
-static unsigned long release_freepages(struct list_head *freelist)
+static void init_page_list(struct page_list *p)
{
- struct page *page, *next;
- unsigned long high_pfn = 0;
-
- list_for_each_entry_safe(page, next, freelist, lru) {
- unsigned long pfn = page_to_pfn(page);
- list_del(&page->lru);
- __free_page(page);
- if (pfn > high_pfn)
- high_pfn = pfn;
- }
-
- return high_pfn;
+ INIT_LIST_HEAD(&p->pages);
+ p->nr_pages = 0;
}
-static void split_map_pages(struct list_head *list)
+static void split_map_pages(struct page_list *freepages)
{
- unsigned int i, order, nr_pages;
+ unsigned int i, order, total_nr_pages;
struct page *page, *next;
LIST_HEAD(tmp_list);
- list_for_each_entry_safe(page, next, list, lru) {
- list_del(&page->lru);
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ total_nr_pages = freepages[order].nr_pages * (1 << order);
+ freepages[order].nr_pages = 0;
+
+ list_for_each_entry_safe(page, next, &freepages[order].pages, lru) {
+ unsigned int nr_pages;
+
+ list_del(&page->lru);
- order = page_private(page);
- nr_pages = 1 << order;
+ nr_pages = 1 << order;
- post_alloc_hook(page, order, __GFP_MOVABLE);
- if (order)
- split_page(page, order);
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ if (order)
+ split_page(page, order);
- for (i = 0; i < nr_pages; i++) {
- list_add(&page->lru, &tmp_list);
- page++;
+ for (i = 0; i < nr_pages; i++) {
+ list_add(&page->lru, &tmp_list);
+ page++;
+ }
}
+ freepages[0].nr_pages += total_nr_pages;
+ list_splice_init(&tmp_list, &freepages[0].pages);
}
+}
- list_splice(&tmp_list, list);
+static unsigned long release_free_list(struct page_list *freepages)
+{
+ int order;
+ unsigned long high_pfn = 0;
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ struct page *page, *next;
+
+ list_for_each_entry_safe(page, next, &freepages[order].pages, lru) {
+ unsigned long pfn = page_to_pfn(page);
+
+ list_del(&page->lru);
+ /*
+ * Convert free pages into post allocation pages, so
+ * that we can free them via __free_page.
+ */
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ __free_pages(page, order);
+ if (pfn > high_pfn)
+ high_pfn = pfn;
+ }
+ freepages[order].nr_pages = 0;
+ }
+ return high_pfn;
}
#ifdef CONFIG_COMPACTION
@@ -583,7 +605,7 @@ static bool compact_unlock_should_abort(
static unsigned long isolate_freepages_block(struct compact_control *cc,
unsigned long *start_pfn,
unsigned long end_pfn,
- struct list_head *freelist,
+ struct page_list *freelist,
unsigned int stride,
bool strict)
{
@@ -657,7 +679,8 @@ static unsigned long isolate_freepages_b
nr_scanned += isolated - 1;
total_isolated += isolated;
cc->nr_freepages += isolated;
- list_add_tail(&page->lru, freelist);
+ list_add_tail(&page->lru, &freelist[order].pages);
+ freelist[order].nr_pages++;
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
@@ -722,7 +745,11 @@ isolate_freepages_range(struct compact_c
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
- LIST_HEAD(freelist);
+ int order;
+ struct page_list tmp_freepages[NR_PAGE_ORDERS];
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ init_page_list(&tmp_freepages[order]);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
@@ -753,7 +780,7 @@ isolate_freepages_range(struct compact_c
break;
isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, &freelist, 0, true);
+ block_end_pfn, tmp_freepages, 0, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
@@ -770,15 +797,15 @@ isolate_freepages_range(struct compact_c
*/
}
- /* __isolate_free_page() does not map the pages */
- split_map_pages(&freelist);
-
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
- release_freepages(&freelist);
+ release_free_list(tmp_freepages);
return 0;
}
+ /* __isolate_free_page() does not map the pages */
+ split_map_pages(tmp_freepages);
+
/* We don't use freelists for anything. */
return pfn;
}
@@ -1481,7 +1508,7 @@ fast_isolate_around(struct compact_contr
if (!page)
return;
- isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
+ isolate_freepages_block(cc, &start_pfn, end_pfn, cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
if (start_pfn == end_pfn && !cc->no_set_skip_hint)
@@ -1610,7 +1637,8 @@ static void fast_isolate_freepages(struc
nr_scanned += nr_isolated - 1;
total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
- list_add_tail(&page->lru, &cc->freepages);
+ list_add_tail(&page->lru, &cc->freepages[order].pages);
+ cc->freepages[order].nr_pages++;
count_compact_events(COMPACTISOLATED, nr_isolated);
} else {
/* If isolation fails, abort the search */
@@ -1687,13 +1715,12 @@ static void isolate_freepages(struct com
unsigned long isolate_start_pfn; /* exact pfn we start at */
unsigned long block_end_pfn; /* end of current pageblock */
unsigned long low_pfn; /* lowest pfn scanner is able to scan */
- struct list_head *freelist = &cc->freepages;
unsigned int stride;
/* Try a small search of the free lists for a candidate */
fast_isolate_freepages(cc);
if (cc->nr_freepages)
- goto splitmap;
+ return;
/*
* Initialise the free scanner. The starting point is where we last
@@ -1753,7 +1780,7 @@ static void isolate_freepages(struct com
/* Found a block suitable for isolating free pages from. */
nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, stride, false);
+ block_end_pfn, cc->freepages, stride, false);
/* Update the skip hint if the full pageblock was scanned */
if (isolate_start_pfn == block_end_pfn)
@@ -1794,10 +1821,6 @@ static void isolate_freepages(struct com
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
-
-splitmap:
- /* __isolate_free_page() does not map the pages */
- split_map_pages(freelist);
}
/*
@@ -1808,23 +1831,22 @@ static struct folio *compaction_alloc(st
{
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ int order = folio_order(src);
- /* this makes migrate_pages() split the source page and retry */
- if (folio_test_large(src) > 0)
- return NULL;
-
- if (list_empty(&cc->freepages)) {
+ if (!cc->freepages[order].nr_pages) {
isolate_freepages(cc);
-
- if (list_empty(&cc->freepages))
+ if (!cc->freepages[order].nr_pages)
return NULL;
}
- dst = list_entry(cc->freepages.next, struct folio, lru);
+ dst = list_first_entry(&cc->freepages[order].pages, struct folio, lru);
+ cc->freepages[order].nr_pages--;
list_del(&dst->lru);
- cc->nr_freepages--;
-
- return dst;
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+ if (order)
+ prep_compound_page(&dst->page, order);
+ cc->nr_freepages -= 1 << order;
+ return page_rmappable_folio(&dst->page);
}
/*
@@ -1835,9 +1857,17 @@ static struct folio *compaction_alloc(st
static void compaction_free(struct folio *dst, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
+ int order = folio_order(dst);
+ struct page *page = &dst->page;
+
+ folio_set_count(dst, 0);
+ free_pages_prepare_fpi_none(page, order);
- list_add(&dst->lru, &cc->freepages);
- cc->nr_freepages++;
+ INIT_LIST_HEAD(&dst->lru);
+
+ list_add(&dst->lru, &cc->freepages[order].pages);
+ cc->freepages[order].nr_pages++;
+ cc->nr_freepages += 1 << order;
}
/* possible outcome of isolate_migratepages */
@@ -2461,6 +2491,7 @@ compact_zone(struct compact_control *cc,
const bool sync = cc->mode != MIGRATE_ASYNC;
bool update_cached;
unsigned int nr_succeeded = 0;
+ int order;
/*
* These counters track activities during zone compaction. Initialize
@@ -2470,7 +2501,8 @@ compact_zone(struct compact_control *cc,
cc->total_free_scanned = 0;
cc->nr_migratepages = 0;
cc->nr_freepages = 0;
- INIT_LIST_HEAD(&cc->freepages);
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ init_page_list(&cc->freepages[order]);
INIT_LIST_HEAD(&cc->migratepages);
cc->migratetype = gfp_migratetype(cc->gfp_mask);
@@ -2656,7 +2688,7 @@ out:
* so we don't leave any returned pages behind in the next attempt.
*/
if (cc->nr_freepages > 0) {
- unsigned long free_pfn = release_freepages(&cc->freepages);
+ unsigned long free_pfn = release_free_list(cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
@@ -2675,7 +2707,6 @@ out:
trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
- VM_BUG_ON(!list_empty(&cc->freepages));
VM_BUG_ON(!list_empty(&cc->migratepages));
return ret;
--- a/mm/internal.h~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/internal.h
@@ -447,6 +447,8 @@ extern void prep_compound_page(struct pa
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
+extern bool free_pages_prepare_fpi_none(struct page *page, unsigned int order);
+
extern int user_min_free_kbytes;
extern void free_unref_page(struct page *page, unsigned int order);
@@ -473,6 +475,11 @@ int split_free_page(struct page *free_pa
/*
* in mm/compaction.c
*/
+
+struct page_list {
+ struct list_head pages;
+ unsigned long nr_pages;
+};
/*
* 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
@@ -481,7 +488,7 @@ int split_free_page(struct page *free_pa
* completes when free_pfn <= migrate_pfn
*/
struct compact_control {
- struct list_head freepages; /* List of free pages to migrate to */
+ struct page_list freepages[NR_PAGE_ORDERS]; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
unsigned int nr_freepages; /* Number of isolated free pages */
unsigned int nr_migratepages; /* Number of pages to migrate */
--- a/mm/page_alloc.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/page_alloc.c
@@ -1179,6 +1179,12 @@ static __always_inline bool free_pages_p
return true;
}
+__always_inline bool free_pages_prepare_fpi_none(struct page *page,
+ unsigned int order)
+{
+ return free_pages_prepare(page, order, FPI_NONE);
+}
+
/*
* Frees a number of pages from the PCP lists
* Assumes all pages on list are in same zone.
_
Patches currently in -mm which might be from ziy@nvidia.com are
mm-compaction-enable-compacting-0-order-folios.patch
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
mm-compaction-optimize-0-order-folio-compaction-with-free-page-split.patch
^ permalink raw reply [flat|nested] 4+ messages in thread* + mm-compaction-add-support-for-0-order-folio-memory-compaction.patch added to mm-unstable branch
@ 2024-01-26 5:44 Andrew Morton
0 siblings, 0 replies; 4+ messages in thread
From: Andrew Morton @ 2024-01-26 5:44 UTC (permalink / raw)
To: mm-commits, yuzhao, ying.huang, willy, vishal.moola, vbabka,
shikemeng, ryan.roberts, mgorman, mcgrof, kirill.shutemov, hannes,
fengwei.yin, david, baolin.wang, a.manzanares, ziy, akpm
The patch titled
Subject: mm/compaction: add support for >0 order folio memory compaction.
has been added to the -mm mm-unstable branch. Its filename is
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
The -mm tree is included into linux-next via the mm-everything
branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
and is updated there every 2-3 working days
------------------------------------------------------
From: Zi Yan <ziy@nvidia.com>
Subject: mm/compaction: add support for >0 order folio memory compaction.
Date: Mon, 22 Jan 2024 22:46:34 -0500
Before last commit, memory compaction only migrates order-0 folios and
skips >0 order folios. Last commit splits all >0 order folios during
compaction. This commit migrates >0 order folios during compaction by
keeping isolated free pages at their original size without splitting them
into order-0 pages and using them directly during migration process.
What is different from the prior implementation:
1. All isolated free pages are kept in a NR_PAGE_ORDERS array of page
lists, where each page list stores free pages in the same order.
2. All free pages are not post_alloc_hook() processed nor buddy pages,
although their orders are stored in first page's private like buddy
pages.
3. During migration, in new page allocation time (i.e., in
compaction_alloc()), free pages are then processed by post_alloc_hook().
When migration fails and a new page is returned (i.e., in
compaction_free()), free pages are restored by reversing the
post_alloc_hook() operations using newly added
free_pages_prepare_fpi_none().
Step 3 is done for a latter optimization that splitting and/or merging
free pages during compaction becomes easier.
Note: without splitting free pages, compaction can end prematurely due to
migration will return -ENOMEM even if there is free pages. This happens
when no order-0 free page exist and compaction_alloc() return NULL.
Link: https://lkml.kernel.org/r/20240123034636.1095672-3-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Adam Manzanares <a.manzanares@samsung.com>
Cc: Baolin Wang <baolin.wang@linux.alibaba.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Huang Ying <ying.huang@intel.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Kemeng Shi <shikemeng@huaweicloud.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Yin Fengwei <fengwei.yin@intel.com>
Cc: Yu Zhao <yuzhao@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
---
mm/compaction.c | 148 +++++++++++++++++++++++++++-------------------
mm/internal.h | 9 ++
mm/page_alloc.c | 6 +
3 files changed, 103 insertions(+), 60 deletions(-)
--- a/mm/compaction.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/compaction.c
@@ -66,45 +66,67 @@ static inline void count_compact_events(
#define COMPACTION_HPAGE_ORDER (PMD_SHIFT - PAGE_SHIFT)
#endif
-static unsigned long release_freepages(struct list_head *freelist)
+static void init_page_list(struct page_list *p)
{
- struct page *page, *next;
- unsigned long high_pfn = 0;
-
- list_for_each_entry_safe(page, next, freelist, lru) {
- unsigned long pfn = page_to_pfn(page);
- list_del(&page->lru);
- __free_page(page);
- if (pfn > high_pfn)
- high_pfn = pfn;
- }
-
- return high_pfn;
+ INIT_LIST_HEAD(&p->pages);
+ p->nr_pages = 0;
}
-static void split_map_pages(struct list_head *list)
+static void split_map_pages(struct page_list *freepages)
{
- unsigned int i, order, nr_pages;
+ unsigned int i, order, total_nr_pages;
struct page *page, *next;
LIST_HEAD(tmp_list);
- list_for_each_entry_safe(page, next, list, lru) {
- list_del(&page->lru);
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ total_nr_pages = freepages[order].nr_pages * (1 << order);
+ freepages[order].nr_pages = 0;
+
+ list_for_each_entry_safe(page, next, &freepages[order].pages, lru) {
+ unsigned int nr_pages;
+
+ list_del(&page->lru);
- order = page_private(page);
- nr_pages = 1 << order;
+ nr_pages = 1 << order;
- post_alloc_hook(page, order, __GFP_MOVABLE);
- if (order)
- split_page(page, order);
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ if (order)
+ split_page(page, order);
- for (i = 0; i < nr_pages; i++) {
- list_add(&page->lru, &tmp_list);
- page++;
+ for (i = 0; i < nr_pages; i++) {
+ list_add(&page->lru, &tmp_list);
+ page++;
+ }
}
+ freepages[0].nr_pages += total_nr_pages;
+ list_splice_init(&tmp_list, &freepages[0].pages);
}
+}
- list_splice(&tmp_list, list);
+static unsigned long release_free_list(struct page_list *freepages)
+{
+ int order;
+ unsigned long high_pfn = 0;
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++) {
+ struct page *page, *next;
+
+ list_for_each_entry_safe(page, next, &freepages[order].pages, lru) {
+ unsigned long pfn = page_to_pfn(page);
+
+ list_del(&page->lru);
+ /*
+ * Convert free pages into post allocation pages, so
+ * that we can free them via __free_page.
+ */
+ post_alloc_hook(page, order, __GFP_MOVABLE);
+ __free_pages(page, order);
+ if (pfn > high_pfn)
+ high_pfn = pfn;
+ }
+ freepages[order].nr_pages = 0;
+ }
+ return high_pfn;
}
#ifdef CONFIG_COMPACTION
@@ -583,7 +605,7 @@ static bool compact_unlock_should_abort(
static unsigned long isolate_freepages_block(struct compact_control *cc,
unsigned long *start_pfn,
unsigned long end_pfn,
- struct list_head *freelist,
+ struct page_list *freelist,
unsigned int stride,
bool strict)
{
@@ -657,7 +679,8 @@ static unsigned long isolate_freepages_b
nr_scanned += isolated - 1;
total_isolated += isolated;
cc->nr_freepages += isolated;
- list_add_tail(&page->lru, freelist);
+ list_add_tail(&page->lru, &freelist[order].pages);
+ freelist[order].nr_pages++;
if (!strict && cc->nr_migratepages <= cc->nr_freepages) {
blockpfn += isolated;
@@ -722,7 +745,11 @@ isolate_freepages_range(struct compact_c
unsigned long start_pfn, unsigned long end_pfn)
{
unsigned long isolated, pfn, block_start_pfn, block_end_pfn;
- LIST_HEAD(freelist);
+ int order;
+ struct page_list tmp_freepages[NR_PAGE_ORDERS];
+
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ init_page_list(&tmp_freepages[order]);
pfn = start_pfn;
block_start_pfn = pageblock_start_pfn(pfn);
@@ -753,7 +780,7 @@ isolate_freepages_range(struct compact_c
break;
isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, &freelist, 0, true);
+ block_end_pfn, tmp_freepages, 0, true);
/*
* In strict mode, isolate_freepages_block() returns 0 if
@@ -770,15 +797,15 @@ isolate_freepages_range(struct compact_c
*/
}
- /* __isolate_free_page() does not map the pages */
- split_map_pages(&freelist);
-
if (pfn < end_pfn) {
/* Loop terminated early, cleanup. */
- release_freepages(&freelist);
+ release_free_list(tmp_freepages);
return 0;
}
+ /* __isolate_free_page() does not map the pages */
+ split_map_pages(tmp_freepages);
+
/* We don't use freelists for anything. */
return pfn;
}
@@ -1481,7 +1508,7 @@ fast_isolate_around(struct compact_contr
if (!page)
return;
- isolate_freepages_block(cc, &start_pfn, end_pfn, &cc->freepages, 1, false);
+ isolate_freepages_block(cc, &start_pfn, end_pfn, cc->freepages, 1, false);
/* Skip this pageblock in the future as it's full or nearly full */
if (start_pfn == end_pfn && !cc->no_set_skip_hint)
@@ -1610,7 +1637,7 @@ static void fast_isolate_freepages(struc
nr_scanned += nr_isolated - 1;
total_isolated += nr_isolated;
cc->nr_freepages += nr_isolated;
- list_add_tail(&page->lru, &cc->freepages);
+ list_add_tail(&page->lru, &cc->freepages[order].pages);
count_compact_events(COMPACTISOLATED, nr_isolated);
} else {
/* If isolation fails, abort the search */
@@ -1687,13 +1714,12 @@ static void isolate_freepages(struct com
unsigned long isolate_start_pfn; /* exact pfn we start at */
unsigned long block_end_pfn; /* end of current pageblock */
unsigned long low_pfn; /* lowest pfn scanner is able to scan */
- struct list_head *freelist = &cc->freepages;
unsigned int stride;
/* Try a small search of the free lists for a candidate */
fast_isolate_freepages(cc);
if (cc->nr_freepages)
- goto splitmap;
+ return;
/*
* Initialise the free scanner. The starting point is where we last
@@ -1753,7 +1779,7 @@ static void isolate_freepages(struct com
/* Found a block suitable for isolating free pages from. */
nr_isolated = isolate_freepages_block(cc, &isolate_start_pfn,
- block_end_pfn, freelist, stride, false);
+ block_end_pfn, cc->freepages, stride, false);
/* Update the skip hint if the full pageblock was scanned */
if (isolate_start_pfn == block_end_pfn)
@@ -1794,10 +1820,6 @@ static void isolate_freepages(struct com
* and the loop terminated due to isolate_start_pfn < low_pfn
*/
cc->free_pfn = isolate_start_pfn;
-
-splitmap:
- /* __isolate_free_page() does not map the pages */
- split_map_pages(freelist);
}
/*
@@ -1808,23 +1830,22 @@ static struct folio *compaction_alloc(st
{
struct compact_control *cc = (struct compact_control *)data;
struct folio *dst;
+ int order = folio_order(src);
- /* this makes migrate_pages() split the source page and retry */
- if (folio_test_large(src) > 0)
- return NULL;
-
- if (list_empty(&cc->freepages)) {
+ if (!cc->freepages[order].nr_pages) {
isolate_freepages(cc);
-
- if (list_empty(&cc->freepages))
+ if (!cc->freepages[order].nr_pages)
return NULL;
}
- dst = list_entry(cc->freepages.next, struct folio, lru);
+ dst = list_first_entry(&cc->freepages[order].pages, struct folio, lru);
+ cc->freepages[order].nr_pages--;
list_del(&dst->lru);
- cc->nr_freepages--;
-
- return dst;
+ post_alloc_hook(&dst->page, order, __GFP_MOVABLE);
+ if (order)
+ prep_compound_page(&dst->page, order);
+ cc->nr_freepages -= 1 << order;
+ return page_rmappable_folio(&dst->page);
}
/*
@@ -1835,9 +1856,17 @@ static struct folio *compaction_alloc(st
static void compaction_free(struct folio *dst, unsigned long data)
{
struct compact_control *cc = (struct compact_control *)data;
+ int order = folio_order(dst);
+ struct page *page = &dst->page;
+
+ folio_set_count(dst, 0);
+ free_pages_prepare_fpi_none(page, order);
- list_add(&dst->lru, &cc->freepages);
- cc->nr_freepages++;
+ INIT_LIST_HEAD(&dst->lru);
+
+ list_add(&dst->lru, &cc->freepages[order].pages);
+ cc->freepages[order].nr_pages++;
+ cc->nr_freepages += 1 << order;
}
/* possible outcome of isolate_migratepages */
@@ -2461,6 +2490,7 @@ compact_zone(struct compact_control *cc,
const bool sync = cc->mode != MIGRATE_ASYNC;
bool update_cached;
unsigned int nr_succeeded = 0;
+ int order;
/*
* These counters track activities during zone compaction. Initialize
@@ -2470,7 +2500,8 @@ compact_zone(struct compact_control *cc,
cc->total_free_scanned = 0;
cc->nr_migratepages = 0;
cc->nr_freepages = 0;
- INIT_LIST_HEAD(&cc->freepages);
+ for (order = 0; order < NR_PAGE_ORDERS; order++)
+ init_page_list(&cc->freepages[order]);
INIT_LIST_HEAD(&cc->migratepages);
cc->migratetype = gfp_migratetype(cc->gfp_mask);
@@ -2656,7 +2687,7 @@ out:
* so we don't leave any returned pages behind in the next attempt.
*/
if (cc->nr_freepages > 0) {
- unsigned long free_pfn = release_freepages(&cc->freepages);
+ unsigned long free_pfn = release_free_list(cc->freepages);
cc->nr_freepages = 0;
VM_BUG_ON(free_pfn == 0);
@@ -2675,7 +2706,6 @@ out:
trace_mm_compaction_end(cc, start_pfn, end_pfn, sync, ret);
- VM_BUG_ON(!list_empty(&cc->freepages));
VM_BUG_ON(!list_empty(&cc->migratepages));
return ret;
--- a/mm/internal.h~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/internal.h
@@ -447,6 +447,8 @@ extern void prep_compound_page(struct pa
extern void post_alloc_hook(struct page *page, unsigned int order,
gfp_t gfp_flags);
+extern bool free_pages_prepare_fpi_none(struct page *page, unsigned int order);
+
extern int user_min_free_kbytes;
extern void free_unref_page(struct page *page, unsigned int order);
@@ -473,6 +475,11 @@ int split_free_page(struct page *free_pa
/*
* in mm/compaction.c
*/
+
+struct page_list {
+ struct list_head pages;
+ unsigned long nr_pages;
+};
/*
* 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
@@ -481,7 +488,7 @@ int split_free_page(struct page *free_pa
* completes when free_pfn <= migrate_pfn
*/
struct compact_control {
- struct list_head freepages; /* List of free pages to migrate to */
+ struct page_list freepages[NR_PAGE_ORDERS]; /* List of free pages to migrate to */
struct list_head migratepages; /* List of pages being migrated */
unsigned int nr_freepages; /* Number of isolated free pages */
unsigned int nr_migratepages; /* Number of pages to migrate */
--- a/mm/page_alloc.c~mm-compaction-add-support-for-0-order-folio-memory-compaction
+++ a/mm/page_alloc.c
@@ -1179,6 +1179,12 @@ static __always_inline bool free_pages_p
return true;
}
+__always_inline bool free_pages_prepare_fpi_none(struct page *page,
+ unsigned int order)
+{
+ return free_pages_prepare(page, order, FPI_NONE);
+}
+
/*
* Frees a number of pages from the PCP lists
* Assumes all pages on list are in same zone.
_
Patches currently in -mm which might be from ziy@nvidia.com are
mm-compaction-enable-compacting-0-order-folios.patch
mm-compaction-add-support-for-0-order-folio-memory-compaction.patch
mm-compaction-optimize-0-order-folio-compaction-with-free-page-split.patch
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