[PATCH v2 00/11] memcg: per cgroup dirty page accounting

[PATCH v2 00/11] memcg: per cgroup dirty page accounting

[Greg Thelen]

Changes since V1:
- Renamed "nfs"/"total_nfs" to "nfs_unstable"/"total_nfs_unstable" in per cgroup
  memory.stat to match /proc/meminfo.

- Avoid lockdep warnings by using rcu_read_[un]lock() in
  mem_cgroup_has_dirty_limit().

- Fixed lockdep issue in mem_cgroup_read_stat() which is exposed by these
  patches.

- Remove redundant comments.

- Rename (for clarity):
  - mem_cgroup_write_page_stat_item -> mem_cgroup_page_stat_item
  - mem_cgroup_read_page_stat_item -> mem_cgroup_nr_pages_item

- Renamed newly created proc files:
  - memory.dirty_bytes -> memory.dirty_limit_in_bytes
  - memory.dirty_background_bytes -> memory.dirty_background_limit_in_bytes

- Removed unnecessary get_ prefix from get_xxx() functions.

- Allow [kKmMgG] suffixes for newly created dirty limit value cgroupfs files.

- Disable softirq rather than hardirq in lock_page_cgroup()

- Made mem_cgroup_move_account_page_stat() inline.

- Ported patches to mmotm-2010-10-13-17-13.


This patch set provides the ability for each cgroup to have independent dirty
page limits.

Limiting dirty memory is like fixing the max amount of dirty (hard to reclaim)
page cache used by a cgroup.  So, in case of multiple cgroup writers, they will
not be able to consume more than their designated share of dirty pages and will
be forced to perform write-out if they cross that limit.

The patches are based on a series proposed by Andrea Righi in Mar 2010.


Overview:
- Add page_cgroup flags to record when pages are dirty, in writeback, or nfs
  unstable.

- Extend mem_cgroup to record the total number of pages in each of the 
  interesting dirty states (dirty, writeback, unstable_nfs).  

- Add dirty parameters similar to the system-wide  /proc/sys/vm/dirty_*
  limits to mem_cgroup.  The mem_cgroup dirty parameters are accessible
  via cgroupfs control files.

- Consider both system and per-memcg dirty limits in page writeback when
  deciding to queue background writeback or block for foreground writeback.


Known shortcomings:
- When a cgroup dirty limit is exceeded, then bdi writeback is employed to
  writeback dirty inodes.  Bdi writeback considers inodes from any cgroup, not
  just inodes contributing dirty pages to the cgroup exceeding its limit.  


Performance data:
- A page fault microbenchmark workload was used to measure performance, which
  can be called in read or write mode:
        f = open(foo. $cpu)
        truncate(f, 4096)
        alarm(60)
        while (1) {
                p = mmap(f, 4096)
                if (write)
			*p = 1
		else
			x = *p
                munmap(p)
        }

- The workload was called for several points in the patch series in different
  modes:
  - s_read is a single threaded reader
  - s_write is a single threaded writer
  - p_read is a 16 thread reader, each operating on a different file
  - p_write is a 16 thread writer, each operating on a different file

- Measurements were collected on a 16 core non-numa system using "perf stat
  --repeat 3".  The -a option was used for parallel (p_*) runs.

- All numbers are page fault rate (M/sec).  Higher is better.

- Patch 04/11 disables softirq in lock_page_cgroup().  There has been some
  discussion about the performance of this change.  To compare the cost of
  disabling softirq in patch 04/11, compare the patch 03 and patch 04 rows.

- To compare the performance of a kernel without non-memcg compare the first and
  last rows, neither has memcg configured.  The first row does not include any
  of these memcg patches.

- To compare the performance of using memcg dirty limits, compare the baseline
  (2nd row titled "w/ memcg") with the the code and memcg enabled (2nd to last
  row titled "all patches").

                           root_cgroup                     child_cgroup
                 s_read s_write p_read p_write    s_read s_write p_read p_write
mmotm w/o memcg   0.424  0.399   0.421  0.395
w/ memcg          0.418  0.389   0.398  0.369      0.414  0.389  0.395  0.369
patch 03/11       0.429  0.394   0.405  0.378      0.427  0.393  0.405  0.379
 create extensible routines
patch 04/11       0.424  0.394   0.400  0.373      0.421  0.389  0.398  0.366
  disable softirq
all patches       0.419  0.379   0.392  0.365      0.416  0.379  0.391  0.362
all patches       0.428  0.395   0.421  0.391
  w/o memcg


Balbir Singh (1):
  memcg: CPU hotplug lockdep warning fix

Greg Thelen (10):
  memcg: add page_cgroup flags for dirty page tracking
  memcg: document cgroup dirty memory interfaces
  memcg: create extensible page stat update routines
  memcg: disable softirq in lock_page_cgroup()
  memcg: add dirty page accounting infrastructure
  memcg: add kernel calls for memcg dirty page stats
  memcg: add dirty limits to mem_cgroup
  memcg: add cgroupfs interface to memcg dirty limits
  writeback: make determine_dirtyable_memory() static.
  memcg: check memcg dirty limits in page writeback

 Documentation/cgroups/memory.txt |   60 ++++++
 fs/nfs/write.c                   |    4 +
 include/linux/memcontrol.h       |   78 +++++++-
 include/linux/page_cgroup.h      |   29 +++
 include/linux/writeback.h        |    2 -
 mm/filemap.c                     |    1 +
 mm/memcontrol.c                  |  408 ++++++++++++++++++++++++++++++++++++--
 mm/page-writeback.c              |  213 +++++++++++++-------
 mm/rmap.c                        |    4 +-
 mm/truncate.c                    |    1 +
 10 files changed, 697 insertions(+), 103 deletions(-)

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[PATCH v2 01/11] memcg: add page_cgroup flags for dirty page tracking

[Greg Thelen]

Add additional flags to page_cgroup to track dirty pages
within a mem_cgroup.

Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
---
 include/linux/page_cgroup.h |   23 +++++++++++++++++++++++
 1 files changed, 23 insertions(+), 0 deletions(-)

diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index 5bb13b3..b59c298 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -40,6 +40,9 @@ enum {
 	PCG_USED, /* this object is in use. */
 	PCG_ACCT_LRU, /* page has been accounted for */
 	PCG_FILE_MAPPED, /* page is accounted as "mapped" */
+	PCG_FILE_DIRTY, /* page is dirty */
+	PCG_FILE_WRITEBACK, /* page is under writeback */
+	PCG_FILE_UNSTABLE_NFS, /* page is NFS unstable */
 	PCG_MIGRATION, /* under page migration */
 };
 
@@ -59,6 +62,10 @@ static inline void ClearPageCgroup##uname(struct page_cgroup *pc)	\
 static inline int TestClearPageCgroup##uname(struct page_cgroup *pc)	\
 	{ return test_and_clear_bit(PCG_##lname, &pc->flags);  }
 
+#define TESTSETPCGFLAG(uname, lname)			\
+static inline int TestSetPageCgroup##uname(struct page_cgroup *pc)	\
+	{ return test_and_set_bit(PCG_##lname, &pc->flags);  }
+
 TESTPCGFLAG(Locked, LOCK)
 
 /* Cache flag is set only once (at allocation) */
@@ -80,6 +87,22 @@ SETPCGFLAG(FileMapped, FILE_MAPPED)
 CLEARPCGFLAG(FileMapped, FILE_MAPPED)
 TESTPCGFLAG(FileMapped, FILE_MAPPED)
 
+SETPCGFLAG(FileDirty, FILE_DIRTY)
+CLEARPCGFLAG(FileDirty, FILE_DIRTY)
+TESTPCGFLAG(FileDirty, FILE_DIRTY)
+TESTCLEARPCGFLAG(FileDirty, FILE_DIRTY)
+TESTSETPCGFLAG(FileDirty, FILE_DIRTY)
+
+SETPCGFLAG(FileWriteback, FILE_WRITEBACK)
+CLEARPCGFLAG(FileWriteback, FILE_WRITEBACK)
+TESTPCGFLAG(FileWriteback, FILE_WRITEBACK)
+
+SETPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS)
+CLEARPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS)
+TESTPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS)
+TESTCLEARPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS)
+TESTSETPCGFLAG(FileUnstableNFS, FILE_UNSTABLE_NFS)
+
 SETPCGFLAG(Migration, MIGRATION)
 CLEARPCGFLAG(Migration, MIGRATION)
 TESTPCGFLAG(Migration, MIGRATION)
-- 
1.7.1

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[PATCH v2 02/11] memcg: document cgroup dirty memory interfaces

[Greg Thelen]

Document cgroup dirty memory interfaces and statistics.

Signed-off-by: Andrea Righi <arighi@develer.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
---
 Documentation/cgroups/memory.txt |   60 ++++++++++++++++++++++++++++++++++++++
 1 files changed, 60 insertions(+), 0 deletions(-)

diff --git a/Documentation/cgroups/memory.txt b/Documentation/cgroups/memory.txt
index 7781857..02bbd6f 100644
--- a/Documentation/cgroups/memory.txt
+++ b/Documentation/cgroups/memory.txt
@@ -385,6 +385,10 @@ mapped_file	- # of bytes of mapped file (includes tmpfs/shmem)
 pgpgin		- # of pages paged in (equivalent to # of charging events).
 pgpgout		- # of pages paged out (equivalent to # of uncharging events).
 swap		- # of bytes of swap usage
+dirty		- # of bytes that are waiting to get written back to the disk.
+writeback	- # of bytes that are actively being written back to the disk.
+nfs_unstable	- # of bytes sent to the NFS server, but not yet committed to
+		the actual storage.
 inactive_anon	- # of bytes of anonymous memory and swap cache memory on
 		LRU list.
 active_anon	- # of bytes of anonymous and swap cache memory on active
@@ -453,6 +457,62 @@ memory under it will be reclaimed.
 You can reset failcnt by writing 0 to failcnt file.
 # echo 0 > .../memory.failcnt
 
+5.5 dirty memory
+
+Control the maximum amount of dirty pages a cgroup can have at any given time.
+
+Limiting dirty memory is like fixing the max amount of dirty (hard to reclaim)
+page cache used by a cgroup.  So, in case of multiple cgroup writers, they will
+not be able to consume more than their designated share of dirty pages and will
+be forced to perform write-out if they cross that limit.
+
+The interface is equivalent to the procfs interface: /proc/sys/vm/dirty_*.  It
+is possible to configure a limit to trigger both a direct writeback or a
+background writeback performed by per-bdi flusher threads.  The root cgroup
+memory.dirty_* control files are read-only and match the contents of
+the /proc/sys/vm/dirty_* files.
+
+Per-cgroup dirty limits can be set using the following files in the cgroupfs:
+
+- memory.dirty_ratio: the amount of dirty memory (expressed as a percentage of
+  cgroup memory) at which a process generating dirty pages will itself start
+  writing out dirty data.
+
+- memory.dirty_limit_in_bytes: the amount of dirty memory (expressed in bytes)
+  in the cgroup at which a process generating dirty pages will start itself
+  writing out dirty data.  Suffix (k, K, m, M, g, or G) can be used to indicate
+  that value is kilo, mega or gigabytes.
+
+  Note: memory.dirty_limit_in_bytes is the counterpart of memory.dirty_ratio.
+  Only one of them may be specified at a time.  When one is written it is
+  immediately taken into account to evaluate the dirty memory limits and the
+  other appears as 0 when read.
+
+- memory.dirty_background_ratio: the amount of dirty memory of the cgroup
+  (expressed as a percentage of cgroup memory) at which background writeback
+  kernel threads will start writing out dirty data.
+
+- memory.dirty_background_limit_in_bytes: the amount of dirty memory (expressed
+  in bytes) in the cgroup at which background writeback kernel threads will
+  start writing out dirty data.  Suffix (k, K, m, M, g, or G) can be used to
+  indicate that value is kilo, mega or gigabytes.
+
+  Note: memory.dirty_background_limit_in_bytes is the counterpart of
+  memory.dirty_background_ratio.  Only one of them may be specified at a time.
+  When one is written it is immediately taken into account to evaluate the dirty
+  memory limits and the other appears as 0 when read.
+
+A cgroup may contain more dirty memory than its dirty limit.  This is possible
+because of the principle that the first cgroup to touch a page is charged for
+it.  Subsequent page counting events (dirty, writeback, nfs_unstable) are also
+counted to the originally charged cgroup.
+
+Example: If page is allocated by a cgroup A task, then the page is charged to
+cgroup A.  If the page is later dirtied by a task in cgroup B, then the cgroup A
+dirty count will be incremented.  If cgroup A is over its dirty limit but cgroup
+B is not, then dirtying a cgroup A page from a cgroup B task may push cgroup A
+over its dirty limit without throttling the dirtying cgroup B task.
+
 6. Hierarchy support
 
 The memory controller supports a deep hierarchy and hierarchical accounting.
-- 
1.7.1

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[PATCH v2 03/11] memcg: create extensible page stat update routines

[Greg Thelen]

Replace usage of the mem_cgroup_update_file_mapped() memcg
statistic update routine with two new routines:
* mem_cgroup_inc_page_stat()
* mem_cgroup_dec_page_stat()

As before, only the file_mapped statistic is managed.  However,
these more general interfaces allow for new statistics to be
more easily added.  New statistics are added with memcg dirty
page accounting.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
---
 include/linux/memcontrol.h |   31 ++++++++++++++++++++++++++++---
 mm/memcontrol.c            |   16 +++++++---------
 mm/rmap.c                  |    4 ++--
 3 files changed, 37 insertions(+), 14 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 159a076..067115c 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -25,6 +25,11 @@ struct page_cgroup;
 struct page;
 struct mm_struct;
 
+/* Stats that can be updated by kernel. */
+enum mem_cgroup_page_stat_item {
+	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
+};
+
 extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
 					struct list_head *dst,
 					unsigned long *scanned, int order,
@@ -121,7 +126,22 @@ static inline bool mem_cgroup_disabled(void)
 	return false;
 }
 
-void mem_cgroup_update_file_mapped(struct page *page, int val);
+void mem_cgroup_update_page_stat(struct page *page,
+				 enum mem_cgroup_page_stat_item idx,
+				 int val);
+
+static inline void mem_cgroup_inc_page_stat(struct page *page,
+					    enum mem_cgroup_page_stat_item idx)
+{
+	mem_cgroup_update_page_stat(page, idx, 1);
+}
+
+static inline void mem_cgroup_dec_page_stat(struct page *page,
+					    enum mem_cgroup_page_stat_item idx)
+{
+	mem_cgroup_update_page_stat(page, idx, -1);
+}
+
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 						gfp_t gfp_mask);
 u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
@@ -293,8 +313,13 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
 {
 }
 
-static inline void mem_cgroup_update_file_mapped(struct page *page,
-							int val)
+static inline void mem_cgroup_inc_page_stat(struct page *page,
+					    enum mem_cgroup_page_stat_item idx)
+{
+}
+
+static inline void mem_cgroup_dec_page_stat(struct page *page,
+					    enum mem_cgroup_page_stat_item idx)
 {
 }
 
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index a4034b6..369879a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -1609,7 +1609,8 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
  * possibility of race condition. If there is, we take a lock.
  */
 
-static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
+void mem_cgroup_update_page_stat(struct page *page,
+				 enum mem_cgroup_page_stat_item idx, int val)
 {
 	struct mem_cgroup *mem;
 	struct page_cgroup *pc = lookup_page_cgroup(page);
@@ -1632,30 +1633,27 @@ static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
 			goto out;
 	}
 
-	this_cpu_add(mem->stat->count[idx], val);
-
 	switch (idx) {
-	case MEM_CGROUP_STAT_FILE_MAPPED:
+	case MEMCG_NR_FILE_MAPPED:
 		if (val > 0)
 			SetPageCgroupFileMapped(pc);
 		else if (!page_mapped(page))
 			ClearPageCgroupFileMapped(pc);
+		idx = MEM_CGROUP_STAT_FILE_MAPPED;
 		break;
 	default:
 		BUG();
 	}
 
+	this_cpu_add(mem->stat->count[idx], val);
+
 out:
 	if (unlikely(need_unlock))
 		unlock_page_cgroup(pc);
 	rcu_read_unlock();
 	return;
 }
-
-void mem_cgroup_update_file_mapped(struct page *page, int val)
-{
-	mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
-}
+EXPORT_SYMBOL(mem_cgroup_update_page_stat);
 
 /*
  * size of first charge trial. "32" comes from vmscan.c's magic value.
diff --git a/mm/rmap.c b/mm/rmap.c
index 1a8bf76..a66ab76 100644
--- a/mm/rmap.c
+++ b/mm/rmap.c
@@ -911,7 +911,7 @@ void page_add_file_rmap(struct page *page)
 {
 	if (atomic_inc_and_test(&page->_mapcount)) {
 		__inc_zone_page_state(page, NR_FILE_MAPPED);
-		mem_cgroup_update_file_mapped(page, 1);
+		mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
 	}
 }
 
@@ -949,7 +949,7 @@ void page_remove_rmap(struct page *page)
 		__dec_zone_page_state(page, NR_ANON_PAGES);
 	} else {
 		__dec_zone_page_state(page, NR_FILE_MAPPED);
-		mem_cgroup_update_file_mapped(page, -1);
+		mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
 	}
 	/*
 	 * It would be tidy to reset the PageAnon mapping here,
-- 
1.7.1

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[PATCH v2 04/11] memcg: disable softirq in lock_page_cgroup()

[Greg Thelen]

If pages are being migrated from a memcg, then updates to that
memcg's page statistics are protected by grabbing a bit spin lock
using lock_page_cgroup().  In an upcoming commit memcg dirty page
accounting will be updating memcg page accounting (specifically:
num writeback pages) from softirq.  Avoid a deadlocking nested
spin lock attempt by disabling softirq on the local processor
when grabbing the page_cgroup bit_spin_lock in lock_page_cgroup().
This avoids the following deadlock:
statistic
      CPU 0             CPU 1
                    inc_file_mapped
                    rcu_read_lock
  start move
  synchronize_rcu
                    lock_page_cgroup
                      softirq
                      test_clear_page_writeback
                      mem_cgroup_dec_page_stat(NR_WRITEBACK)
                      rcu_read_lock
                      lock_page_cgroup   /* deadlock */
                      unlock_page_cgroup
                      rcu_read_unlock
                    unlock_page_cgroup
                    rcu_read_unlock

By disabling softirq in lock_page_cgroup, nested calls are avoided.
The softirq would be delayed until after inc_file_mapped enables
softirq when calling unlock_page_cgroup().

The normal, fast path, of memcg page stat updates typically
does not need to call lock_page_cgroup(), so this change does
not affect the performance of the common case page accounting.

Signed-off-by: Andrea Righi <arighi@develer.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
---
 include/linux/page_cgroup.h |    6 ++++++
 1 files changed, 6 insertions(+), 0 deletions(-)

diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
index b59c298..0585546 100644
--- a/include/linux/page_cgroup.h
+++ b/include/linux/page_cgroup.h
@@ -3,6 +3,8 @@
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR
 #include <linux/bit_spinlock.h>
+#include <linux/hardirq.h>
+
 /*
  * Page Cgroup can be considered as an extended mem_map.
  * A page_cgroup page is associated with every page descriptor. The
@@ -119,12 +121,16 @@ static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
 
 static inline void lock_page_cgroup(struct page_cgroup *pc)
 {
+	/* This routine is only deadlock safe from softirq or lower. */
+	VM_BUG_ON(in_irq());
+	local_bh_disable();
 	bit_spin_lock(PCG_LOCK, &pc->flags);
 }
 
 static inline void unlock_page_cgroup(struct page_cgroup *pc)
 {
 	bit_spin_unlock(PCG_LOCK, &pc->flags);
+	local_bh_enable();
 }
 
 #else /* CONFIG_CGROUP_MEM_RES_CTLR */
-- 
1.7.1

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[PATCH v2 05/11] memcg: add dirty page accounting infrastructure

[Greg Thelen]

Add memcg routines to track dirty, writeback, and unstable_NFS pages.
These routines are not yet used by the kernel to count such pages.
A later change adds kernel calls to these new routines.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
---
 include/linux/memcontrol.h |    3 ++
 mm/memcontrol.c            |   86 +++++++++++++++++++++++++++++++++++++++----
 2 files changed, 81 insertions(+), 8 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 067115c..ef2eec7 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -28,6 +28,9 @@ struct mm_struct;
 /* Stats that can be updated by kernel. */
 enum mem_cgroup_page_stat_item {
 	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
+	MEMCG_NR_FILE_DIRTY, /* # of dirty pages in page cache */
+	MEMCG_NR_FILE_WRITEBACK, /* # of pages under writeback */
+	MEMCG_NR_FILE_UNSTABLE_NFS, /* # of NFS unstable pages */
 };
 
 extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 369879a..3884a85 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -85,10 +85,13 @@ enum mem_cgroup_stat_index {
 	 */
 	MEM_CGROUP_STAT_CACHE, 	   /* # of pages charged as cache */
 	MEM_CGROUP_STAT_RSS,	   /* # of pages charged as anon rss */
-	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
 	MEM_CGROUP_STAT_PGPGIN_COUNT,	/* # of pages paged in */
 	MEM_CGROUP_STAT_PGPGOUT_COUNT,	/* # of pages paged out */
 	MEM_CGROUP_STAT_SWAPOUT, /* # of pages, swapped out */
+	MEM_CGROUP_STAT_FILE_MAPPED,  /* # of pages charged as file rss */
+	MEM_CGROUP_STAT_FILE_DIRTY,	/* # of dirty pages in page cache */
+	MEM_CGROUP_STAT_FILE_WRITEBACK,		/* # of pages under writeback */
+	MEM_CGROUP_STAT_FILE_UNSTABLE_NFS,	/* # of NFS unstable pages */
 	MEM_CGROUP_STAT_DATA, /* end of data requires synchronization */
 	/* incremented at every  pagein/pageout */
 	MEM_CGROUP_EVENTS = MEM_CGROUP_STAT_DATA,
@@ -1641,6 +1644,44 @@ void mem_cgroup_update_page_stat(struct page *page,
 			ClearPageCgroupFileMapped(pc);
 		idx = MEM_CGROUP_STAT_FILE_MAPPED;
 		break;
+
+	case MEMCG_NR_FILE_DIRTY:
+		/* Use Test{Set,Clear} to only un/charge the memcg once. */
+		if (val > 0) {
+			if (TestSetPageCgroupFileDirty(pc))
+				val = 0;
+		} else {
+			if (!TestClearPageCgroupFileDirty(pc))
+				val = 0;
+		}
+		idx = MEM_CGROUP_STAT_FILE_DIRTY;
+		break;
+
+	case MEMCG_NR_FILE_WRITEBACK:
+		/*
+		 * This counter is adjusted while holding the mapping's
+		 * tree_lock.  Therefore there is no race between settings and
+		 * clearing of this flag.
+		 */
+		if (val > 0)
+			SetPageCgroupFileWriteback(pc);
+		else
+			ClearPageCgroupFileWriteback(pc);
+		idx = MEM_CGROUP_STAT_FILE_WRITEBACK;
+		break;
+
+	case MEMCG_NR_FILE_UNSTABLE_NFS:
+		/* Use Test{Set,Clear} to only un/charge the memcg once. */
+		if (val > 0) {
+			if (TestSetPageCgroupFileUnstableNFS(pc))
+				val = 0;
+		} else {
+			if (!TestClearPageCgroupFileUnstableNFS(pc))
+				val = 0;
+		}
+		idx = MEM_CGROUP_STAT_FILE_UNSTABLE_NFS;
+		break;
+
 	default:
 		BUG();
 	}
@@ -2145,6 +2186,17 @@ static void __mem_cgroup_commit_charge(struct mem_cgroup *mem,
 	memcg_check_events(mem, pc->page);
 }
 
+static inline
+void mem_cgroup_move_account_page_stat(struct mem_cgroup *from,
+				       struct mem_cgroup *to,
+				       enum mem_cgroup_stat_index idx)
+{
+	preempt_disable();
+	__this_cpu_dec(from->stat->count[idx]);
+	__this_cpu_inc(to->stat->count[idx]);
+	preempt_enable();
+}
+
 /**
  * __mem_cgroup_move_account - move account of the page
  * @pc:	page_cgroup of the page.
@@ -2171,13 +2223,18 @@ static void __mem_cgroup_move_account(struct page_cgroup *pc,
 	VM_BUG_ON(!PageCgroupUsed(pc));
 	VM_BUG_ON(pc->mem_cgroup != from);
 
-	if (PageCgroupFileMapped(pc)) {
-		/* Update mapped_file data for mem_cgroup */
-		preempt_disable();
-		__this_cpu_dec(from->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
-		__this_cpu_inc(to->stat->count[MEM_CGROUP_STAT_FILE_MAPPED]);
-		preempt_enable();
-	}
+	if (PageCgroupFileMapped(pc))
+		mem_cgroup_move_account_page_stat(from, to,
+					MEM_CGROUP_STAT_FILE_MAPPED);
+	if (PageCgroupFileDirty(pc))
+		mem_cgroup_move_account_page_stat(from, to,
+					MEM_CGROUP_STAT_FILE_DIRTY);
+	if (PageCgroupFileWriteback(pc))
+		mem_cgroup_move_account_page_stat(from, to,
+					MEM_CGROUP_STAT_FILE_WRITEBACK);
+	if (PageCgroupFileUnstableNFS(pc))
+		mem_cgroup_move_account_page_stat(from, to,
+					MEM_CGROUP_STAT_FILE_UNSTABLE_NFS);
 	mem_cgroup_charge_statistics(from, pc, false);
 	if (uncharge)
 		/* This is not "cancel", but cancel_charge does all we need. */
@@ -3552,6 +3609,9 @@ enum {
 	MCS_PGPGIN,
 	MCS_PGPGOUT,
 	MCS_SWAP,
+	MCS_FILE_DIRTY,
+	MCS_WRITEBACK,
+	MCS_UNSTABLE_NFS,
 	MCS_INACTIVE_ANON,
 	MCS_ACTIVE_ANON,
 	MCS_INACTIVE_FILE,
@@ -3574,6 +3634,9 @@ struct {
 	{"pgpgin", "total_pgpgin"},
 	{"pgpgout", "total_pgpgout"},
 	{"swap", "total_swap"},
+	{"dirty", "total_dirty"},
+	{"writeback", "total_writeback"},
+	{"nfs_unstable", "total_nfs_unstable"},
 	{"inactive_anon", "total_inactive_anon"},
 	{"active_anon", "total_active_anon"},
 	{"inactive_file", "total_inactive_file"},
@@ -3603,6 +3666,13 @@ mem_cgroup_get_local_stat(struct mem_cgroup *mem, struct mcs_total_stat *s)
 		s->stat[MCS_SWAP] += val * PAGE_SIZE;
 	}
 
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_DIRTY);
+	s->stat[MCS_FILE_DIRTY] += val * PAGE_SIZE;
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_WRITEBACK);
+	s->stat[MCS_WRITEBACK] += val * PAGE_SIZE;
+	val = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_UNSTABLE_NFS);
+	s->stat[MCS_UNSTABLE_NFS] += val * PAGE_SIZE;
+
 	/* per zone stat */
 	val = mem_cgroup_get_local_zonestat(mem, LRU_INACTIVE_ANON);
 	s->stat[MCS_INACTIVE_ANON] += val * PAGE_SIZE;
-- 
1.7.1

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[PATCH v2 06/11] memcg: add kernel calls for memcg dirty page stats

[Greg Thelen]

Add calls into memcg dirty page accounting.  Notify memcg when pages
transition between clean, file dirty, writeback, and unstable nfs.
This allows the memory controller to maintain an accurate view of
the amount of its memory that is dirty.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
---
 fs/nfs/write.c      |    4 ++++
 mm/filemap.c        |    1 +
 mm/page-writeback.c |    4 ++++
 mm/truncate.c       |    1 +
 4 files changed, 10 insertions(+), 0 deletions(-)

diff --git a/fs/nfs/write.c b/fs/nfs/write.c
index 4c14c17..a3c39f7 100644
--- a/fs/nfs/write.c
+++ b/fs/nfs/write.c
@@ -450,6 +450,7 @@ nfs_mark_request_commit(struct nfs_page *req)
 			NFS_PAGE_TAG_COMMIT);
 	nfsi->ncommit++;
 	spin_unlock(&inode->i_lock);
+	mem_cgroup_inc_page_stat(req->wb_page, MEMCG_NR_FILE_UNSTABLE_NFS);
 	inc_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 	inc_bdi_stat(req->wb_page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 	__mark_inode_dirty(inode, I_DIRTY_DATASYNC);
@@ -461,6 +462,7 @@ nfs_clear_request_commit(struct nfs_page *req)
 	struct page *page = req->wb_page;
 
 	if (test_and_clear_bit(PG_CLEAN, &(req)->wb_flags)) {
+		mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_UNSTABLE_NFS);
 		dec_zone_page_state(page, NR_UNSTABLE_NFS);
 		dec_bdi_stat(page->mapping->backing_dev_info, BDI_RECLAIMABLE);
 		return 1;
@@ -1316,6 +1318,8 @@ nfs_commit_list(struct inode *inode, struct list_head *head, int how)
 		req = nfs_list_entry(head->next);
 		nfs_list_remove_request(req);
 		nfs_mark_request_commit(req);
+		mem_cgroup_dec_page_stat(req->wb_page,
+					 MEMCG_NR_FILE_UNSTABLE_NFS);
 		dec_zone_page_state(req->wb_page, NR_UNSTABLE_NFS);
 		dec_bdi_stat(req->wb_page->mapping->backing_dev_info,
 				BDI_RECLAIMABLE);
diff --git a/mm/filemap.c b/mm/filemap.c
index 49b2d2e..f6bd6f2 100644
--- a/mm/filemap.c
+++ b/mm/filemap.c
@@ -146,6 +146,7 @@ void __remove_from_page_cache(struct page *page)
 	 * having removed the page entirely.
 	 */
 	if (PageDirty(page) && mapping_cap_account_dirty(mapping)) {
+		mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_DIRTY);
 		dec_zone_page_state(page, NR_FILE_DIRTY);
 		dec_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
 	}
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index b840afa..820eb66 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -1114,6 +1114,7 @@ int __set_page_dirty_no_writeback(struct page *page)
 void account_page_dirtied(struct page *page, struct address_space *mapping)
 {
 	if (mapping_cap_account_dirty(mapping)) {
+		mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_DIRTY);
 		__inc_zone_page_state(page, NR_FILE_DIRTY);
 		__inc_zone_page_state(page, NR_DIRTIED);
 		__inc_bdi_stat(mapping->backing_dev_info, BDI_RECLAIMABLE);
@@ -1303,6 +1304,7 @@ int clear_page_dirty_for_io(struct page *page)
 		 * for more comments.
 		 */
 		if (TestClearPageDirty(page)) {
+			mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_DIRTY);
 			dec_zone_page_state(page, NR_FILE_DIRTY);
 			dec_bdi_stat(mapping->backing_dev_info,
 					BDI_RECLAIMABLE);
@@ -1333,6 +1335,7 @@ int test_clear_page_writeback(struct page *page)
 				__dec_bdi_stat(bdi, BDI_WRITEBACK);
 				__bdi_writeout_inc(bdi);
 			}
+			mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_WRITEBACK);
 		}
 		spin_unlock_irqrestore(&mapping->tree_lock, flags);
 	} else {
@@ -1360,6 +1363,7 @@ int test_set_page_writeback(struct page *page)
 						PAGECACHE_TAG_WRITEBACK);
 			if (bdi_cap_account_writeback(bdi))
 				__inc_bdi_stat(bdi, BDI_WRITEBACK);
+			mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_WRITEBACK);
 		}
 		if (!PageDirty(page))
 			radix_tree_tag_clear(&mapping->page_tree,
diff --git a/mm/truncate.c b/mm/truncate.c
index cd94607..54cca83 100644
--- a/mm/truncate.c
+++ b/mm/truncate.c
@@ -76,6 +76,7 @@ void cancel_dirty_page(struct page *page, unsigned int account_size)
 	if (TestClearPageDirty(page)) {
 		struct address_space *mapping = page->mapping;
 		if (mapping && mapping_cap_account_dirty(mapping)) {
+			mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_DIRTY);
 			dec_zone_page_state(page, NR_FILE_DIRTY);
 			dec_bdi_stat(mapping->backing_dev_info,
 					BDI_RECLAIMABLE);
-- 
1.7.1

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[PATCH v2 07/11] memcg: add dirty limits to mem_cgroup

[Greg Thelen]

Extend mem_cgroup to contain dirty page limits.  Also add routines
allowing the kernel to query the dirty usage of a memcg.

These interfaces not used by the kernel yet.  A subsequent commit
will add kernel calls to utilize these new routines.

Signed-off-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Andrea Righi <arighi@develer.com>
---
 include/linux/memcontrol.h |   44 ++++++++++
 mm/memcontrol.c            |  186 +++++++++++++++++++++++++++++++++++++++++++-
 2 files changed, 229 insertions(+), 1 deletions(-)

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index ef2eec7..6f3a136 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -19,6 +19,7 @@
 
 #ifndef _LINUX_MEMCONTROL_H
 #define _LINUX_MEMCONTROL_H
+#include <linux/writeback.h>
 #include <linux/cgroup.h>
 struct mem_cgroup;
 struct page_cgroup;
@@ -33,6 +34,30 @@ enum mem_cgroup_page_stat_item {
 	MEMCG_NR_FILE_UNSTABLE_NFS, /* # of NFS unstable pages */
 };
 
+/* Cgroup memory statistics items exported to the kernel. */
+enum mem_cgroup_nr_pages_item {
+	MEMCG_NR_DIRTYABLE_PAGES,
+	MEMCG_NR_RECLAIM_PAGES,
+	MEMCG_NR_WRITEBACK,
+	MEMCG_NR_DIRTY_WRITEBACK_PAGES,
+};
+
+/* Dirty memory parameters */
+struct vm_dirty_param {
+	int dirty_ratio;
+	int dirty_background_ratio;
+	unsigned long dirty_bytes;
+	unsigned long dirty_background_bytes;
+};
+
+static inline void global_vm_dirty_param(struct vm_dirty_param *param)
+{
+	param->dirty_ratio = vm_dirty_ratio;
+	param->dirty_bytes = vm_dirty_bytes;
+	param->dirty_background_ratio = dirty_background_ratio;
+	param->dirty_background_bytes = dirty_background_bytes;
+}
+
 extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
 					struct list_head *dst,
 					unsigned long *scanned, int order,
@@ -145,6 +170,10 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 	mem_cgroup_update_page_stat(page, idx, -1);
 }
 
+bool mem_cgroup_has_dirty_limit(void);
+void vm_dirty_param(struct vm_dirty_param *param);
+s64 mem_cgroup_page_stat(enum mem_cgroup_nr_pages_item item);
+
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 						gfp_t gfp_mask);
 u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
@@ -326,6 +355,21 @@ static inline void mem_cgroup_dec_page_stat(struct page *page,
 {
 }
 
+static inline bool mem_cgroup_has_dirty_limit(void)
+{
+	return false;
+}
+
+static inline void vm_dirty_param(struct vm_dirty_param *param)
+{
+	global_vm_dirty_param(param);
+}
+
+static inline s64 mem_cgroup_page_stat(enum mem_cgroup_nr_pages_item item)
+{
+	return -ENOSYS;
+}
+
 static inline
 unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
 					    gfp_t gfp_mask)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 3884a85..eef25fe 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -233,6 +233,10 @@ struct mem_cgroup {
 	atomic_t	refcnt;
 
 	unsigned int	swappiness;
+
+	/* control memory cgroup dirty pages */
+	struct vm_dirty_param dirty_param;
+
 	/* OOM-Killer disable */
 	int		oom_kill_disable;
 
@@ -1149,6 +1153,178 @@ static unsigned int get_swappiness(struct mem_cgroup *memcg)
 	return swappiness;
 }
 
+/*
+ * Returns a snapshot of the current dirty limits which is not synchronized with
+ * the routines that change the dirty limits.  If this routine races with an
+ * update to the dirty bytes/ratio value, then the caller must handle the case
+ * where both dirty_[background_]_ratio and _bytes are set.
+ */
+static void __mem_cgroup_dirty_param(struct vm_dirty_param *param,
+				     struct mem_cgroup *mem)
+{
+	if (mem && !mem_cgroup_is_root(mem)) {
+		param->dirty_ratio = mem->dirty_param.dirty_ratio;
+		param->dirty_bytes = mem->dirty_param.dirty_bytes;
+		param->dirty_background_ratio =
+			mem->dirty_param.dirty_background_ratio;
+		param->dirty_background_bytes =
+			mem->dirty_param.dirty_background_bytes;
+	} else {
+		global_vm_dirty_param(param);
+	}
+}
+
+/*
+ * Get dirty memory parameters of the current memcg or global values (if memory
+ * cgroups are disabled or querying the root cgroup).
+ *
+ * The current task may be moved to other cgroup while we access cgroup changing
+ * the task's dirty limit.  But a precise check is meaningless because the task
+ * can be moved after our access and writeback tends to take long time.  At
+ * least, "memcg" will not be freed while holding rcu_read_lock().
+ */
+void vm_dirty_param(struct vm_dirty_param *param)
+{
+	struct mem_cgroup *memcg;
+
+	if (mem_cgroup_disabled()) {
+		global_vm_dirty_param(param);
+		return;
+	}
+
+	rcu_read_lock();
+	memcg = mem_cgroup_from_task(current);
+	__mem_cgroup_dirty_param(param, memcg);
+	rcu_read_unlock();
+}
+
+/*
+ * Return true if the current memory cgroup has local dirty memory settings.
+ * There is an allowed race between the current task migrating in-to/out-of the
+ * root cgroup while this routine runs.  So the return value may be incorrect if
+ * the current task is being simultaneously migrated.
+ */
+bool mem_cgroup_has_dirty_limit(void)
+{
+	struct mem_cgroup *mem;
+	bool ret;
+
+	if (mem_cgroup_disabled())
+		return false;
+
+	rcu_read_lock();
+	mem = mem_cgroup_from_task(current);
+	ret = mem && !mem_cgroup_is_root(mem);
+	rcu_read_unlock();
+
+	return ret;
+}
+
+static inline bool mem_cgroup_can_swap(struct mem_cgroup *memcg)
+{
+	if (!do_swap_account)
+		return nr_swap_pages > 0;
+	return !memcg->memsw_is_minimum &&
+		(res_counter_read_u64(&memcg->memsw, RES_LIMIT) > 0);
+}
+
+static s64 mem_cgroup_local_page_stat(struct mem_cgroup *mem,
+				      enum mem_cgroup_nr_pages_item item)
+{
+	s64 ret;
+
+	switch (item) {
+	case MEMCG_NR_DIRTYABLE_PAGES:
+		ret = mem_cgroup_read_stat(mem, LRU_ACTIVE_FILE) +
+			mem_cgroup_read_stat(mem, LRU_INACTIVE_FILE);
+		if (mem_cgroup_can_swap(mem))
+			ret += mem_cgroup_read_stat(mem, LRU_ACTIVE_ANON) +
+				mem_cgroup_read_stat(mem, LRU_INACTIVE_ANON);
+		break;
+	case MEMCG_NR_RECLAIM_PAGES:
+		ret = mem_cgroup_read_stat(mem,	MEM_CGROUP_STAT_FILE_DIRTY) +
+			mem_cgroup_read_stat(mem,
+					     MEM_CGROUP_STAT_FILE_UNSTABLE_NFS);
+		break;
+	case MEMCG_NR_WRITEBACK:
+		ret = mem_cgroup_read_stat(mem, MEM_CGROUP_STAT_FILE_WRITEBACK);
+		break;
+	case MEMCG_NR_DIRTY_WRITEBACK_PAGES:
+		ret = mem_cgroup_read_stat(mem,
+					   MEM_CGROUP_STAT_FILE_WRITEBACK) +
+			mem_cgroup_read_stat(mem,
+					     MEM_CGROUP_STAT_FILE_UNSTABLE_NFS);
+		break;
+	default:
+		BUG();
+		break;
+	}
+	return ret;
+}
+
+static unsigned long long
+memcg_hierarchical_free_pages(struct mem_cgroup *mem)
+{
+	struct cgroup *cgroup;
+	unsigned long long min_free, free;
+
+	min_free = res_counter_read_u64(&mem->res, RES_LIMIT) -
+		res_counter_read_u64(&mem->res, RES_USAGE);
+	cgroup = mem->css.cgroup;
+	if (!mem->use_hierarchy)
+		goto out;
+
+	while (cgroup->parent) {
+		cgroup = cgroup->parent;
+		mem = mem_cgroup_from_cont(cgroup);
+		if (!mem->use_hierarchy)
+			break;
+		free = res_counter_read_u64(&mem->res, RES_LIMIT) -
+			res_counter_read_u64(&mem->res, RES_USAGE);
+		min_free = min(min_free, free);
+	}
+out:
+	/* Translate free memory in pages */
+	return min_free >> PAGE_SHIFT;
+}
+
+/*
+ * mem_cgroup_page_stat() - get memory cgroup file cache statistics
+ * @item:      memory statistic item exported to the kernel
+ *
+ * Return the accounted statistic value.
+ */
+s64 mem_cgroup_page_stat(enum mem_cgroup_nr_pages_item item)
+{
+	struct mem_cgroup *mem;
+	struct mem_cgroup *iter;
+	s64 value;
+
+	rcu_read_lock();
+	mem = mem_cgroup_from_task(current);
+	if (mem && !mem_cgroup_is_root(mem)) {
+		/*
+		 * If we're looking for dirtyable pages we need to evaluate
+		 * free pages depending on the limit and usage of the parents
+		 * first of all.
+		 */
+		if (item == MEMCG_NR_DIRTYABLE_PAGES)
+			value = memcg_hierarchical_free_pages(mem);
+		else
+			value = 0;
+		/*
+		 * Recursively evaluate page statistics against all cgroup
+		 * under hierarchy tree
+		 */
+		for_each_mem_cgroup_tree(iter, mem)
+			value += mem_cgroup_local_page_stat(iter, item);
+	} else
+		value = -EINVAL;
+	rcu_read_unlock();
+
+	return value;
+}
+
 static void mem_cgroup_start_move(struct mem_cgroup *mem)
 {
 	int cpu;
@@ -4452,8 +4628,16 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
 	spin_lock_init(&mem->reclaim_param_lock);
 	INIT_LIST_HEAD(&mem->oom_notify);
 
-	if (parent)
+	if (parent) {
 		mem->swappiness = get_swappiness(parent);
+		__mem_cgroup_dirty_param(&mem->dirty_param, parent);
+	} else {
+		/*
+		 * The root cgroup dirty_param field is not used, instead,
+		 * system-wide dirty limits are used.
+		 */
+	}
+
 	atomic_set(&mem->refcnt, 1);
 	mem->move_charge_at_immigrate = 0;
 	mutex_init(&mem->thresholds_lock);
-- 
1.7.1

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[PATCH v2 08/11] memcg: CPU hotplug lockdep warning fix

[Greg Thelen]

From: Balbir Singh <balbir@linux.vnet.ibm.com>

memcg has lockdep warnings (sleep inside rcu lock)

From: Balbir Singh <balbir@linux.vnet.ibm.com>

Recent move to get_online_cpus() ends up calling get_online_cpus() from
mem_cgroup_read_stat(). However mem_cgroup_read_stat() is called under rcu
lock. get_online_cpus() can sleep. The dirty limit patches expose
this BUG more readily due to their usage of mem_cgroup_page_stat()

This patch address this issue as identified by lockdep and moves the
hotplug protection to a higher layer. This might increase the time
required to hotplug, but not by much.

Warning messages

BUG: sleeping function called from invalid context at kernel/cpu.c:62
in_atomic(): 0, irqs_disabled(): 0, pid: 6325, name: pagetest
2 locks held by pagetest/6325:
do_page_fault+0x27d/0x4a0
mem_cgroup_page_stat+0x0/0x23f
Pid: 6325, comm: pagetest Not tainted 2.6.36-rc5-mm1+ #201
Call Trace:
[<ffffffff81041224>] __might_sleep+0x12d/0x131
[<ffffffff8104f4af>] get_online_cpus+0x1c/0x51
[<ffffffff8110eedb>] mem_cgroup_read_stat+0x27/0xa3
[<ffffffff811125d2>] mem_cgroup_page_stat+0x131/0x23f
[<ffffffff811124a1>] ? mem_cgroup_page_stat+0x0/0x23f
[<ffffffff810d57c3>] global_dirty_limits+0x42/0xf8
[<ffffffff810d58b3>] throttle_vm_writeout+0x3a/0xb4
[<ffffffff810dc2f8>] shrink_zone+0x3e6/0x3f8
[<ffffffff81074a35>] ? ktime_get_ts+0xb2/0xbf
[<ffffffff810dd1aa>] do_try_to_free_pages+0x106/0x478
[<ffffffff810dd601>] try_to_free_mem_cgroup_pages+0xe5/0x14c
[<ffffffff8110f947>] mem_cgroup_hierarchical_reclaim+0x314/0x3a2
[<ffffffff81111b31>] __mem_cgroup_try_charge+0x29b/0x593
[<ffffffff8111194a>] ? __mem_cgroup_try_charge+0xb4/0x593
[<ffffffff81071258>] ? local_clock+0x40/0x59
[<ffffffff81009015>] ? sched_clock+0x9/0xd
[<ffffffff810710d5>] ? sched_clock_local+0x1c/0x82
[<ffffffff8111398a>] mem_cgroup_charge_common+0x4b/0x76
[<ffffffff81141469>] ? bio_add_page+0x36/0x38
[<ffffffff81113ba9>] mem_cgroup_cache_charge+0x1f4/0x214
[<ffffffff810cd195>] add_to_page_cache_locked+0x4a/0x148
....

Acked-by: Greg Thelen <gthelen@google.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
---
 mm/memcontrol.c |    4 ++--
 1 files changed, 2 insertions(+), 2 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index eef25fe..1e4c9d2 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -588,7 +588,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
 	int cpu;
 	s64 val = 0;
 
-	get_online_cpus();
 	for_each_online_cpu(cpu)
 		val += per_cpu(mem->stat->count[idx], cpu);
 #ifdef CONFIG_HOTPLUG_CPU
@@ -596,7 +595,6 @@ static s64 mem_cgroup_read_stat(struct mem_cgroup *mem,
 	val += mem->nocpu_base.count[idx];
 	spin_unlock(&mem->pcp_counter_lock);
 #endif
-	put_online_cpus();
 	return val;
 }
 
@@ -1300,6 +1298,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_nr_pages_item item)
 	struct mem_cgroup *iter;
 	s64 value;
 
+	get_online_cpus();
 	rcu_read_lock();
 	mem = mem_cgroup_from_task(current);
 	if (mem && !mem_cgroup_is_root(mem)) {
@@ -1321,6 +1320,7 @@ s64 mem_cgroup_page_stat(enum mem_cgroup_nr_pages_item item)
 	} else
 		value = -EINVAL;
 	rcu_read_unlock();
+	put_online_cpus();
 
 	return value;
 }
-- 
1.7.1

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[PATCH v2 09/11] memcg: add cgroupfs interface to memcg dirty limits

[Greg Thelen]

Add cgroupfs interface to memcg dirty page limits:
  Direct write-out is controlled with:
  - memory.dirty_ratio
  - memory.dirty_limit_in_bytes

  Background write-out is controlled with:
  - memory.dirty_background_ratio
  - memory.dirty_background_limit_bytes

Other memcg cgroupfs files support 'M', 'm', 'k', 'K', 'g'
and 'G' suffixes for byte counts.  This patch provides the
same functionality for memory.dirty_limit_in_bytes and
memory.dirty_background_limit_bytes.

Signed-off-by: Andrea Righi <arighi@develer.com>
Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
---
 mm/memcontrol.c |  116 +++++++++++++++++++++++++++++++++++++++++++++++++++++++
 1 files changed, 116 insertions(+), 0 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1e4c9d2..4f5a103 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -100,6 +100,13 @@ enum mem_cgroup_stat_index {
 	MEM_CGROUP_STAT_NSTATS,
 };
 
+enum {
+	MEM_CGROUP_DIRTY_RATIO,
+	MEM_CGROUP_DIRTY_LIMIT_IN_BYTES,
+	MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
+	MEM_CGROUP_DIRTY_BACKGROUND_LIMIT_IN_BYTES,
+};
+
 struct mem_cgroup_stat_cpu {
 	s64 count[MEM_CGROUP_STAT_NSTATS];
 };
@@ -4306,6 +4313,91 @@ static int mem_cgroup_oom_control_write(struct cgroup *cgrp,
 	return 0;
 }
 
+static u64 mem_cgroup_dirty_read(struct cgroup *cgrp, struct cftype *cft)
+{
+	struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+	bool root;
+
+	root = mem_cgroup_is_root(mem);
+
+	switch (cft->private) {
+	case MEM_CGROUP_DIRTY_RATIO:
+		return root ? vm_dirty_ratio : mem->dirty_param.dirty_ratio;
+	case MEM_CGROUP_DIRTY_LIMIT_IN_BYTES:
+		return root ? vm_dirty_bytes : mem->dirty_param.dirty_bytes;
+	case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
+		return root ? dirty_background_ratio :
+			mem->dirty_param.dirty_background_ratio;
+	case MEM_CGROUP_DIRTY_BACKGROUND_LIMIT_IN_BYTES:
+		return root ? dirty_background_bytes :
+			mem->dirty_param.dirty_background_bytes;
+	default:
+		BUG();
+	}
+}
+
+static int
+mem_cgroup_dirty_write_string(struct cgroup *cgrp, struct cftype *cft,
+				const char *buffer)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+	int type = cft->private;
+	int ret = -EINVAL;
+	unsigned long long val;
+
+	if (cgrp->parent == NULL)
+		return ret;
+
+	switch (type) {
+	case MEM_CGROUP_DIRTY_LIMIT_IN_BYTES:
+		/* This function does all necessary parse...reuse it */
+		ret = res_counter_memparse_write_strategy(buffer, &val);
+		if (ret)
+			break;
+		memcg->dirty_param.dirty_bytes = val;
+		memcg->dirty_param.dirty_ratio  = 0;
+		break;
+	case MEM_CGROUP_DIRTY_BACKGROUND_LIMIT_IN_BYTES:
+		ret = res_counter_memparse_write_strategy(buffer, &val);
+		if (ret)
+			break;
+		memcg->dirty_param.dirty_background_bytes = val;
+		memcg->dirty_param.dirty_background_ratio = 0;
+		break;
+	default:
+		BUG();
+		break;
+	}
+	return ret;
+}
+
+static int
+mem_cgroup_dirty_write(struct cgroup *cgrp, struct cftype *cft, u64 val)
+{
+	struct mem_cgroup *memcg = mem_cgroup_from_cont(cgrp);
+	int type = cft->private;
+
+	if (cgrp->parent == NULL)
+		return -EINVAL;
+	if ((type == MEM_CGROUP_DIRTY_RATIO ||
+	     type == MEM_CGROUP_DIRTY_BACKGROUND_RATIO) && val > 100)
+		return -EINVAL;
+	switch (type) {
+	case MEM_CGROUP_DIRTY_RATIO:
+		memcg->dirty_param.dirty_ratio = val;
+		memcg->dirty_param.dirty_bytes = 0;
+		break;
+	case MEM_CGROUP_DIRTY_BACKGROUND_RATIO:
+		memcg->dirty_param.dirty_background_ratio = val;
+		memcg->dirty_param.dirty_background_bytes = 0;
+		break;
+	default:
+		BUG();
+		break;
+	}
+	return 0;
+}
+
 static struct cftype mem_cgroup_files[] = {
 	{
 		.name = "usage_in_bytes",
@@ -4369,6 +4461,30 @@ static struct cftype mem_cgroup_files[] = {
 		.unregister_event = mem_cgroup_oom_unregister_event,
 		.private = MEMFILE_PRIVATE(_OOM_TYPE, OOM_CONTROL),
 	},
+	{
+		.name = "dirty_ratio",
+		.read_u64 = mem_cgroup_dirty_read,
+		.write_u64 = mem_cgroup_dirty_write,
+		.private = MEM_CGROUP_DIRTY_RATIO,
+	},
+	{
+		.name = "dirty_limit_in_bytes",
+		.read_u64 = mem_cgroup_dirty_read,
+		.write_string = mem_cgroup_dirty_write_string,
+		.private = MEM_CGROUP_DIRTY_LIMIT_IN_BYTES,
+	},
+	{
+		.name = "dirty_background_ratio",
+		.read_u64 = mem_cgroup_dirty_read,
+		.write_u64 = mem_cgroup_dirty_write,
+		.private = MEM_CGROUP_DIRTY_BACKGROUND_RATIO,
+	},
+	{
+		.name = "dirty_background_limit_in_bytes",
+		.read_u64 = mem_cgroup_dirty_read,
+		.write_string = mem_cgroup_dirty_write_string,
+		.private = MEM_CGROUP_DIRTY_BACKGROUND_LIMIT_IN_BYTES,
+	},
 };
 
 #ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
-- 
1.7.1

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[PATCH v2 10/11] writeback: make determine_dirtyable_memory() static.

[Greg Thelen]

The determine_dirtyable_memory() function is not used outside of
page writeback.  Make the routine static.  No functional change.
Just a cleanup in preparation for a change that adds memcg dirty
limits consideration into global_dirty_limits().

Signed-off-by: Andrea Righi <arighi@develer.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
---
 include/linux/writeback.h |    2 -
 mm/page-writeback.c       |  122 ++++++++++++++++++++++----------------------
 2 files changed, 61 insertions(+), 63 deletions(-)

diff --git a/include/linux/writeback.h b/include/linux/writeback.h
index c7299d2..c18e374 100644
--- a/include/linux/writeback.h
+++ b/include/linux/writeback.h
@@ -105,8 +105,6 @@ extern int vm_highmem_is_dirtyable;
 extern int block_dump;
 extern int laptop_mode;
 
-extern unsigned long determine_dirtyable_memory(void);
-
 extern int dirty_background_ratio_handler(struct ctl_table *table, int write,
 		void __user *buffer, size_t *lenp,
 		loff_t *ppos);
diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index 820eb66..a0bb3e2 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -132,6 +132,67 @@ static struct prop_descriptor vm_completions;
 static struct prop_descriptor vm_dirties;
 
 /*
+ * Work out the current dirty-memory clamping and background writeout
+ * thresholds.
+ *
+ * The main aim here is to lower them aggressively if there is a lot of mapped
+ * memory around.  To avoid stressing page reclaim with lots of unreclaimable
+ * pages.  It is better to clamp down on writers than to start swapping, and
+ * performing lots of scanning.
+ *
+ * We only allow 1/2 of the currently-unmapped memory to be dirtied.
+ *
+ * We don't permit the clamping level to fall below 5% - that is getting rather
+ * excessive.
+ *
+ * We make sure that the background writeout level is below the adjusted
+ * clamping level.
+ */
+
+static unsigned long highmem_dirtyable_memory(unsigned long total)
+{
+#ifdef CONFIG_HIGHMEM
+	int node;
+	unsigned long x = 0;
+
+	for_each_node_state(node, N_HIGH_MEMORY) {
+		struct zone *z =
+			&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
+
+		x += zone_page_state(z, NR_FREE_PAGES) +
+		     zone_reclaimable_pages(z);
+	}
+	/*
+	 * Make sure that the number of highmem pages is never larger
+	 * than the number of the total dirtyable memory. This can only
+	 * occur in very strange VM situations but we want to make sure
+	 * that this does not occur.
+	 */
+	return min(x, total);
+#else
+	return 0;
+#endif
+}
+
+/**
+ * determine_dirtyable_memory - amount of memory that may be used
+ *
+ * Returns the numebr of pages that can currently be freed and used
+ * by the kernel for direct mappings.
+ */
+static unsigned long determine_dirtyable_memory(void)
+{
+	unsigned long x;
+
+	x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();
+
+	if (!vm_highmem_is_dirtyable)
+		x -= highmem_dirtyable_memory(x);
+
+	return x + 1;	/* Ensure that we never return 0 */
+}
+
+/*
  * couple the period to the dirty_ratio:
  *
  *   period/2 ~ roundup_pow_of_two(dirty limit)
@@ -337,67 +398,6 @@ int bdi_set_max_ratio(struct backing_dev_info *bdi, unsigned max_ratio)
 EXPORT_SYMBOL(bdi_set_max_ratio);
 
 /*
- * Work out the current dirty-memory clamping and background writeout
- * thresholds.
- *
- * The main aim here is to lower them aggressively if there is a lot of mapped
- * memory around.  To avoid stressing page reclaim with lots of unreclaimable
- * pages.  It is better to clamp down on writers than to start swapping, and
- * performing lots of scanning.
- *
- * We only allow 1/2 of the currently-unmapped memory to be dirtied.
- *
- * We don't permit the clamping level to fall below 5% - that is getting rather
- * excessive.
- *
- * We make sure that the background writeout level is below the adjusted
- * clamping level.
- */
-
-static unsigned long highmem_dirtyable_memory(unsigned long total)
-{
-#ifdef CONFIG_HIGHMEM
-	int node;
-	unsigned long x = 0;
-
-	for_each_node_state(node, N_HIGH_MEMORY) {
-		struct zone *z =
-			&NODE_DATA(node)->node_zones[ZONE_HIGHMEM];
-
-		x += zone_page_state(z, NR_FREE_PAGES) +
-		     zone_reclaimable_pages(z);
-	}
-	/*
-	 * Make sure that the number of highmem pages is never larger
-	 * than the number of the total dirtyable memory. This can only
-	 * occur in very strange VM situations but we want to make sure
-	 * that this does not occur.
-	 */
-	return min(x, total);
-#else
-	return 0;
-#endif
-}
-
-/**
- * determine_dirtyable_memory - amount of memory that may be used
- *
- * Returns the numebr of pages that can currently be freed and used
- * by the kernel for direct mappings.
- */
-unsigned long determine_dirtyable_memory(void)
-{
-	unsigned long x;
-
-	x = global_page_state(NR_FREE_PAGES) + global_reclaimable_pages();
-
-	if (!vm_highmem_is_dirtyable)
-		x -= highmem_dirtyable_memory(x);
-
-	return x + 1;	/* Ensure that we never return 0 */
-}
-
-/*
  * global_dirty_limits - background-writeback and dirty-throttling thresholds
  *
  * Calculate the dirty thresholds based on sysctl parameters
-- 
1.7.1

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[PATCH v2 11/11] memcg: check memcg dirty limits in page writeback

[Greg Thelen]

If the current process is in a non-root memcg, then
global_dirty_limits() will consider the memcg dirty limit.
This allows different cgroups to have distinct dirty limits
which trigger direct and background writeback at different
levels.

Signed-off-by: Andrea Righi <arighi@develer.com>
Signed-off-by: Greg Thelen <gthelen@google.com>
---
 mm/page-writeback.c |   89 +++++++++++++++++++++++++++++++++++++++++---------
 1 files changed, 73 insertions(+), 16 deletions(-)

diff --git a/mm/page-writeback.c b/mm/page-writeback.c
index a0bb3e2..9b34f01 100644
--- a/mm/page-writeback.c
+++ b/mm/page-writeback.c
@@ -180,7 +180,7 @@ static unsigned long highmem_dirtyable_memory(unsigned long total)
  * Returns the numebr of pages that can currently be freed and used
  * by the kernel for direct mappings.
  */
-static unsigned long determine_dirtyable_memory(void)
+static unsigned long global_dirtyable_memory(void)
 {
 	unsigned long x;
 
@@ -192,6 +192,58 @@ static unsigned long determine_dirtyable_memory(void)
 	return x + 1;	/* Ensure that we never return 0 */
 }
 
+static unsigned long dirtyable_memory(void)
+{
+	unsigned long memory;
+	s64 memcg_memory;
+
+	memory = global_dirtyable_memory();
+	if (!mem_cgroup_has_dirty_limit())
+		return memory;
+	memcg_memory = mem_cgroup_page_stat(MEMCG_NR_DIRTYABLE_PAGES);
+	BUG_ON(memcg_memory < 0);
+
+	return min((unsigned long)memcg_memory, memory);
+}
+
+static long reclaimable_pages(void)
+{
+	s64 ret;
+
+	if (!mem_cgroup_has_dirty_limit())
+		return global_page_state(NR_FILE_DIRTY) +
+			global_page_state(NR_UNSTABLE_NFS);
+	ret = mem_cgroup_page_stat(MEMCG_NR_RECLAIM_PAGES);
+	BUG_ON(ret < 0);
+
+	return ret;
+}
+
+static long writeback_pages(void)
+{
+	s64 ret;
+
+	if (!mem_cgroup_has_dirty_limit())
+		return global_page_state(NR_WRITEBACK);
+	ret = mem_cgroup_page_stat(MEMCG_NR_WRITEBACK);
+	BUG_ON(ret < 0);
+
+	return ret;
+}
+
+static unsigned long dirty_writeback_pages(void)
+{
+	s64 ret;
+
+	if (!mem_cgroup_has_dirty_limit())
+		return global_page_state(NR_UNSTABLE_NFS) +
+			global_page_state(NR_WRITEBACK);
+	ret = mem_cgroup_page_stat(MEMCG_NR_DIRTY_WRITEBACK_PAGES);
+	BUG_ON(ret < 0);
+
+	return ret;
+}
+
 /*
  * couple the period to the dirty_ratio:
  *
@@ -204,8 +256,8 @@ static int calc_period_shift(void)
 	if (vm_dirty_bytes)
 		dirty_total = vm_dirty_bytes / PAGE_SIZE;
 	else
-		dirty_total = (vm_dirty_ratio * determine_dirtyable_memory()) /
-				100;
+		dirty_total = (vm_dirty_ratio * global_dirtyable_memory()) /
+			100;
 	return 2 + ilog2(dirty_total - 1);
 }
 
@@ -410,18 +462,23 @@ void global_dirty_limits(unsigned long *pbackground, unsigned long *pdirty)
 {
 	unsigned long background;
 	unsigned long dirty;
-	unsigned long available_memory = determine_dirtyable_memory();
+	unsigned long available_memory = dirtyable_memory();
 	struct task_struct *tsk;
+	struct vm_dirty_param dirty_param;
 
-	if (vm_dirty_bytes)
-		dirty = DIV_ROUND_UP(vm_dirty_bytes, PAGE_SIZE);
+	vm_dirty_param(&dirty_param);
+
+	if (dirty_param.dirty_bytes)
+		dirty = DIV_ROUND_UP(dirty_param.dirty_bytes, PAGE_SIZE);
 	else
-		dirty = (vm_dirty_ratio * available_memory) / 100;
+		dirty = (dirty_param.dirty_ratio * available_memory) / 100;
 
-	if (dirty_background_bytes)
-		background = DIV_ROUND_UP(dirty_background_bytes, PAGE_SIZE);
+	if (dirty_param.dirty_background_bytes)
+		background = DIV_ROUND_UP(dirty_param.dirty_background_bytes,
+					  PAGE_SIZE);
 	else
-		background = (dirty_background_ratio * available_memory) / 100;
+		background = (dirty_param.dirty_background_ratio *
+			      available_memory) / 100;
 
 	if (background >= dirty)
 		background = dirty / 2;
@@ -493,9 +550,8 @@ static void balance_dirty_pages(struct address_space *mapping,
 			.range_cyclic	= 1,
 		};
 
-		nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
-					global_page_state(NR_UNSTABLE_NFS);
-		nr_writeback = global_page_state(NR_WRITEBACK);
+		nr_reclaimable = reclaimable_pages();
+		nr_writeback = writeback_pages();
 
 		global_dirty_limits(&background_thresh, &dirty_thresh);
 
@@ -652,6 +708,7 @@ void throttle_vm_writeout(gfp_t gfp_mask)
 {
 	unsigned long background_thresh;
 	unsigned long dirty_thresh;
+	unsigned long dirty;
 
         for ( ; ; ) {
 		global_dirty_limits(&background_thresh, &dirty_thresh);
@@ -662,9 +719,9 @@ void throttle_vm_writeout(gfp_t gfp_mask)
                  */
                 dirty_thresh += dirty_thresh / 10;      /* wheeee... */
 
-                if (global_page_state(NR_UNSTABLE_NFS) +
-			global_page_state(NR_WRITEBACK) <= dirty_thresh)
-                        	break;
+		dirty = dirty_writeback_pages();
+		if (dirty <= dirty_thresh)
+			break;
                 congestion_wait(BLK_RW_ASYNC, HZ/10);
 
 		/*
-- 
1.7.1

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Re: [PATCH v2 04/11] memcg: disable softirq in lock_page_cgroup()

[Minchan Kim]

On Sat, Oct 16, 2010 at 6:14 AM, Greg Thelen <gthelen@google.com> wrote:
> If pages are being migrated from a memcg, then updates to that
> memcg's page statistics are protected by grabbing a bit spin lock
> using lock_page_cgroup().  In an upcoming commit memcg dirty page
> accounting will be updating memcg page accounting (specifically:
> num writeback pages) from softirq.  Avoid a deadlocking nested
> spin lock attempt by disabling softirq on the local processor
> when grabbing the page_cgroup bit_spin_lock in lock_page_cgroup().
> This avoids the following deadlock:
> statistic
>      CPU 0             CPU 1
>                    inc_file_mapped
>                    rcu_read_lock
>  start move
>  synchronize_rcu
>                    lock_page_cgroup
>                      softirq
>                      test_clear_page_writeback
>                      mem_cgroup_dec_page_stat(NR_WRITEBACK)
>                      rcu_read_lock
>                      lock_page_cgroup   /* deadlock */
>                      unlock_page_cgroup
>                      rcu_read_unlock
>                    unlock_page_cgroup
>                    rcu_read_unlock
>
> By disabling softirq in lock_page_cgroup, nested calls are avoided.
> The softirq would be delayed until after inc_file_mapped enables
> softirq when calling unlock_page_cgroup().
>
> The normal, fast path, of memcg page stat updates typically
> does not need to call lock_page_cgroup(), so this change does
> not affect the performance of the common case page accounting.
>
> Signed-off-by: Andrea Righi <arighi@develer.com>
> Signed-off-by: Greg Thelen <gthelen@google.com>
> ---
>  include/linux/page_cgroup.h |    6 ++++++
>  1 files changed, 6 insertions(+), 0 deletions(-)
>
> diff --git a/include/linux/page_cgroup.h b/include/linux/page_cgroup.h
> index b59c298..0585546 100644
> --- a/include/linux/page_cgroup.h
> +++ b/include/linux/page_cgroup.h
> @@ -3,6 +3,8 @@
>
>  #ifdef CONFIG_CGROUP_MEM_RES_CTLR
>  #include <linux/bit_spinlock.h>
> +#include <linux/hardirq.h>
> +
>  /*
>  * Page Cgroup can be considered as an extended mem_map.
>  * A page_cgroup page is associated with every page descriptor. The
> @@ -119,12 +121,16 @@ static inline enum zone_type page_cgroup_zid(struct page_cgroup *pc)
>
>  static inline void lock_page_cgroup(struct page_cgroup *pc)
>  {
> +       /* This routine is only deadlock safe from softirq or lower. */
> +       VM_BUG_ON(in_irq());
> +       local_bh_disable();
>        bit_spin_lock(PCG_LOCK, &pc->flags);
>  }
>
>  static inline void unlock_page_cgroup(struct page_cgroup *pc)
>  {
>        bit_spin_unlock(PCG_LOCK, &pc->flags);
> +       local_bh_enable();
>  }
>
>  #else /* CONFIG_CGROUP_MEM_RES_CTLR */
> --
> 1.7.1
>
>

Please, see recent Kame's patch.
http://lkml.org/lkml/2010/10/15/54

-- 
Kind regards,
Minchan Kim

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Re: [PATCH v2 02/11] memcg: document cgroup dirty memory interfaces

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:30 -0700
Greg Thelen <gthelen@google.com> wrote:

> Document cgroup dirty memory interfaces and statistics.
> 
> Signed-off-by: Andrea Righi <arighi@develer.com>
> Signed-off-by: Greg Thelen <gthelen@google.com>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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Re: [PATCH v2 03/11] memcg: create extensible page stat update routines

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:31 -0700
Greg Thelen <gthelen@google.com> wrote:

> Replace usage of the mem_cgroup_update_file_mapped() memcg
> statistic update routine with two new routines:
> * mem_cgroup_inc_page_stat()
> * mem_cgroup_dec_page_stat()
> 
> As before, only the file_mapped statistic is managed.  However,
> these more general interfaces allow for new statistics to be
> more easily added.  New statistics are added with memcg dirty
> page accounting.
> 
> Signed-off-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: Andrea Righi <arighi@develer.com>

Acked-y: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>


> ---
>  include/linux/memcontrol.h |   31 ++++++++++++++++++++++++++++---
>  mm/memcontrol.c            |   16 +++++++---------
>  mm/rmap.c                  |    4 ++--
>  3 files changed, 37 insertions(+), 14 deletions(-)
> 
> diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
> index 159a076..067115c 100644
> --- a/include/linux/memcontrol.h
> +++ b/include/linux/memcontrol.h
> @@ -25,6 +25,11 @@ struct page_cgroup;
>  struct page;
>  struct mm_struct;
>  
> +/* Stats that can be updated by kernel. */
> +enum mem_cgroup_page_stat_item {
> +	MEMCG_NR_FILE_MAPPED, /* # of pages charged as file rss */
> +};
> +
>  extern unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
>  					struct list_head *dst,
>  					unsigned long *scanned, int order,
> @@ -121,7 +126,22 @@ static inline bool mem_cgroup_disabled(void)
>  	return false;
>  }
>  
> -void mem_cgroup_update_file_mapped(struct page *page, int val);
> +void mem_cgroup_update_page_stat(struct page *page,
> +				 enum mem_cgroup_page_stat_item idx,
> +				 int val);
> +
> +static inline void mem_cgroup_inc_page_stat(struct page *page,
> +					    enum mem_cgroup_page_stat_item idx)
> +{
> +	mem_cgroup_update_page_stat(page, idx, 1);
> +}
> +
> +static inline void mem_cgroup_dec_page_stat(struct page *page,
> +					    enum mem_cgroup_page_stat_item idx)
> +{
> +	mem_cgroup_update_page_stat(page, idx, -1);
> +}
> +
>  unsigned long mem_cgroup_soft_limit_reclaim(struct zone *zone, int order,
>  						gfp_t gfp_mask);
>  u64 mem_cgroup_get_limit(struct mem_cgroup *mem);
> @@ -293,8 +313,13 @@ mem_cgroup_print_oom_info(struct mem_cgroup *memcg, struct task_struct *p)
>  {
>  }
>  
> -static inline void mem_cgroup_update_file_mapped(struct page *page,
> -							int val)
> +static inline void mem_cgroup_inc_page_stat(struct page *page,
> +					    enum mem_cgroup_page_stat_item idx)
> +{
> +}
> +
> +static inline void mem_cgroup_dec_page_stat(struct page *page,
> +					    enum mem_cgroup_page_stat_item idx)
>  {
>  }
>  
> diff --git a/mm/memcontrol.c b/mm/memcontrol.c
> index a4034b6..369879a 100644
> --- a/mm/memcontrol.c
> +++ b/mm/memcontrol.c
> @@ -1609,7 +1609,8 @@ bool mem_cgroup_handle_oom(struct mem_cgroup *mem, gfp_t mask)
>   * possibility of race condition. If there is, we take a lock.
>   */
>  
> -static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
> +void mem_cgroup_update_page_stat(struct page *page,
> +				 enum mem_cgroup_page_stat_item idx, int val)
>  {
>  	struct mem_cgroup *mem;
>  	struct page_cgroup *pc = lookup_page_cgroup(page);
> @@ -1632,30 +1633,27 @@ static void mem_cgroup_update_file_stat(struct page *page, int idx, int val)
>  			goto out;
>  	}
>  
> -	this_cpu_add(mem->stat->count[idx], val);
> -
>  	switch (idx) {
> -	case MEM_CGROUP_STAT_FILE_MAPPED:
> +	case MEMCG_NR_FILE_MAPPED:
>  		if (val > 0)
>  			SetPageCgroupFileMapped(pc);
>  		else if (!page_mapped(page))
>  			ClearPageCgroupFileMapped(pc);
> +		idx = MEM_CGROUP_STAT_FILE_MAPPED;
>  		break;
>  	default:
>  		BUG();
>  	}
>  
> +	this_cpu_add(mem->stat->count[idx], val);
> +
>  out:
>  	if (unlikely(need_unlock))
>  		unlock_page_cgroup(pc);
>  	rcu_read_unlock();
>  	return;
>  }
> -
> -void mem_cgroup_update_file_mapped(struct page *page, int val)
> -{
> -	mem_cgroup_update_file_stat(page, MEM_CGROUP_STAT_FILE_MAPPED, val);
> -}
> +EXPORT_SYMBOL(mem_cgroup_update_page_stat);
>  
>  /*
>   * size of first charge trial. "32" comes from vmscan.c's magic value.
> diff --git a/mm/rmap.c b/mm/rmap.c
> index 1a8bf76..a66ab76 100644
> --- a/mm/rmap.c
> +++ b/mm/rmap.c
> @@ -911,7 +911,7 @@ void page_add_file_rmap(struct page *page)
>  {
>  	if (atomic_inc_and_test(&page->_mapcount)) {
>  		__inc_zone_page_state(page, NR_FILE_MAPPED);
> -		mem_cgroup_update_file_mapped(page, 1);
> +		mem_cgroup_inc_page_stat(page, MEMCG_NR_FILE_MAPPED);
>  	}
>  }
>  
> @@ -949,7 +949,7 @@ void page_remove_rmap(struct page *page)
>  		__dec_zone_page_state(page, NR_ANON_PAGES);
>  	} else {
>  		__dec_zone_page_state(page, NR_FILE_MAPPED);
> -		mem_cgroup_update_file_mapped(page, -1);
> +		mem_cgroup_dec_page_stat(page, MEMCG_NR_FILE_MAPPED);
>  	}
>  	/*
>  	 * It would be tidy to reset the PageAnon mapping here,
> -- 
> 1.7.1
> 
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Re: [PATCH v2 04/11] memcg: disable softirq in lock_page_cgroup()

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:32 -0700
Greg Thelen <gthelen@google.com> wrote:

> If pages are being migrated from a memcg, then updates to that
> memcg's page statistics are protected by grabbing a bit spin lock
> using lock_page_cgroup().  In an upcoming commit memcg dirty page
> accounting will be updating memcg page accounting (specifically:
> num writeback pages) from softirq.  Avoid a deadlocking nested
> spin lock attempt by disabling softirq on the local processor
> when grabbing the page_cgroup bit_spin_lock in lock_page_cgroup().
> This avoids the following deadlock:
> statistic
>       CPU 0             CPU 1
>                     inc_file_mapped
>                     rcu_read_lock
>   start move
>   synchronize_rcu
>                     lock_page_cgroup
>                       softirq
>                       test_clear_page_writeback
>                       mem_cgroup_dec_page_stat(NR_WRITEBACK)
>                       rcu_read_lock
>                       lock_page_cgroup   /* deadlock */
>                       unlock_page_cgroup
>                       rcu_read_unlock
>                     unlock_page_cgroup
>                     rcu_read_unlock
> 
> By disabling softirq in lock_page_cgroup, nested calls are avoided.
> The softirq would be delayed until after inc_file_mapped enables
> softirq when calling unlock_page_cgroup().
> 
> The normal, fast path, of memcg page stat updates typically
> does not need to call lock_page_cgroup(), so this change does
> not affect the performance of the common case page accounting.
> 
> Signed-off-by: Andrea Righi <arighi@develer.com>
> Signed-off-by: Greg Thelen <gthelen@google.com>

I have a patch for this problem.
So, could you reorder patch as

	1,2,3,5,6,7,8,9,10,11 

I'll post an add-on patch."12"

move_charge performance improbement patches will be posted later.

Thanks,
-Kame

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Re: [PATCH v2 05/11] memcg: add dirty page accounting infrastructure

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:33 -0700
Greg Thelen <gthelen@google.com> wrote:

> Add memcg routines to track dirty, writeback, and unstable_NFS pages.
> These routines are not yet used by the kernel to count such pages.
> A later change adds kernel calls to these new routines.
> 
> Signed-off-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: Andrea Righi <arighi@develer.com>

BTW, please add "Changelog" for each patch in a series.

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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Re: [PATCH v2 07/11] memcg: add dirty limits to mem_cgroup

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:35 -0700
Greg Thelen <gthelen@google.com> wrote:

> Extend mem_cgroup to contain dirty page limits.  Also add routines
> allowing the kernel to query the dirty usage of a memcg.
> 
> These interfaces not used by the kernel yet.  A subsequent commit
> will add kernel calls to utilize these new routines.
> 
> Signed-off-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: Andrea Righi <arighi@develer.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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Re: [PATCH v2 08/11] memcg: CPU hotplug lockdep warning fix

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:36 -0700
Greg Thelen <gthelen@google.com> wrote:

> From: Balbir Singh <balbir@linux.vnet.ibm.com>
> 
> memcg has lockdep warnings (sleep inside rcu lock)
> 
> From: Balbir Singh <balbir@linux.vnet.ibm.com>
> 
> Recent move to get_online_cpus() ends up calling get_online_cpus() from
> mem_cgroup_read_stat(). However mem_cgroup_read_stat() is called under rcu
> lock. get_online_cpus() can sleep. The dirty limit patches expose
> this BUG more readily due to their usage of mem_cgroup_page_stat()
> 
> This patch address this issue as identified by lockdep and moves the
> hotplug protection to a higher layer. This might increase the time
> required to hotplug, but not by much.
> 
> Warning messages
> 
> BUG: sleeping function called from invalid context at kernel/cpu.c:62
> in_atomic(): 0, irqs_disabled(): 0, pid: 6325, name: pagetest
> 2 locks held by pagetest/6325:
> do_page_fault+0x27d/0x4a0
> mem_cgroup_page_stat+0x0/0x23f
> Pid: 6325, comm: pagetest Not tainted 2.6.36-rc5-mm1+ #201
> Call Trace:
> [<ffffffff81041224>] __might_sleep+0x12d/0x131
> [<ffffffff8104f4af>] get_online_cpus+0x1c/0x51
> [<ffffffff8110eedb>] mem_cgroup_read_stat+0x27/0xa3
> [<ffffffff811125d2>] mem_cgroup_page_stat+0x131/0x23f
> [<ffffffff811124a1>] ? mem_cgroup_page_stat+0x0/0x23f
> [<ffffffff810d57c3>] global_dirty_limits+0x42/0xf8
> [<ffffffff810d58b3>] throttle_vm_writeout+0x3a/0xb4
> [<ffffffff810dc2f8>] shrink_zone+0x3e6/0x3f8
> [<ffffffff81074a35>] ? ktime_get_ts+0xb2/0xbf
> [<ffffffff810dd1aa>] do_try_to_free_pages+0x106/0x478
> [<ffffffff810dd601>] try_to_free_mem_cgroup_pages+0xe5/0x14c
> [<ffffffff8110f947>] mem_cgroup_hierarchical_reclaim+0x314/0x3a2
> [<ffffffff81111b31>] __mem_cgroup_try_charge+0x29b/0x593
> [<ffffffff8111194a>] ? __mem_cgroup_try_charge+0xb4/0x593
> [<ffffffff81071258>] ? local_clock+0x40/0x59
> [<ffffffff81009015>] ? sched_clock+0x9/0xd
> [<ffffffff810710d5>] ? sched_clock_local+0x1c/0x82
> [<ffffffff8111398a>] mem_cgroup_charge_common+0x4b/0x76
> [<ffffffff81141469>] ? bio_add_page+0x36/0x38
> [<ffffffff81113ba9>] mem_cgroup_cache_charge+0x1f4/0x214
> [<ffffffff810cd195>] add_to_page_cache_locked+0x4a/0x148
> ....
> 
> Acked-by: Greg Thelen <gthelen@google.com>
> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>

Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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Re: [PATCH v2 09/11] memcg: add cgroupfs interface to memcg dirty limits

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:37 -0700
Greg Thelen <gthelen@google.com> wrote:

> Add cgroupfs interface to memcg dirty page limits:
>   Direct write-out is controlled with:
>   - memory.dirty_ratio
>   - memory.dirty_limit_in_bytes
> 
>   Background write-out is controlled with:
>   - memory.dirty_background_ratio
>   - memory.dirty_background_limit_bytes
> 
> Other memcg cgroupfs files support 'M', 'm', 'k', 'K', 'g'
> and 'G' suffixes for byte counts.  This patch provides the
> same functionality for memory.dirty_limit_in_bytes and
> memory.dirty_background_limit_bytes.
> 
> Signed-off-by: Andrea Righi <arighi@develer.com>
> Signed-off-by: Balbir Singh <balbir@linux.vnet.ibm.com>
> Signed-off-by: Greg Thelen <gthelen@google.com>
Acked-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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Re: [PATCH v2 10/11] writeback: make determine_dirtyable_memory() static.

[KAMEZAWA Hiroyuki]

On Fri, 15 Oct 2010 14:14:38 -0700
Greg Thelen <gthelen@google.com> wrote:

> The determine_dirtyable_memory() function is not used outside of
> page writeback.  Make the routine static.  No functional change.
> Just a cleanup in preparation for a change that adds memcg dirty
> limits consideration into global_dirty_limits().
> 
> Signed-off-by: Andrea Righi <arighi@develer.com>
> Signed-off-by: Greg Thelen <gthelen@google.com>

Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>

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