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Commit cf8496ea authored by Shaohua Li's avatar Shaohua Li Committed by Linus Torvalds
Browse files

proc: show MADV_FREE pages info in smaps 

Show MADV_FREE pages info of each vma in smaps.  The interface is for
diganose or monitoring purpose, userspace could use it to understand
what happens in the application.  Since userspace could dirty MADV_FREE
pages without notice from kernel, this interface is the only place we
can get accurate accounting info about MADV_FREE pages.

[mhocko@kernel.org: update Documentation/filesystems/proc.txt]
Link: http://lkml.kernel.org/r/89efde633559de1ec07444f2ef0f4963a97a2ce8.1487965799.git.shli@fb.com


Signed-off-by: default avatarShaohua Li <shli@fb.com>
Acked-by: default avatarJohannes Weiner <hannes@cmpxchg.org>
Acked-by: default avatarMinchan Kim <minchan@kernel.org>
Acked-by: default avatarMichal Hocko <mhocko@suse.com>
Acked-by: default avatarHillf Danton <hillf.zj@alibaba-inc.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Mel Gorman <mgorman@techsingularity.net>
Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
parent 93e06c7a

Documentation/filesystems/proc.txt

+6 −0
Original line number Diff line number Diff line
@@ -413,6 +413,7 @@ Private_Clean: 0 kB 
Private_Dirty:         0 kB

Referenced:          892 kB

Anonymous:             0 kB

LazyFree:              0 kB

AnonHugePages:         0 kB

ShmemPmdMapped:        0 kB

Shared_Hugetlb:        0 kB
@@ -442,6 +443,11 @@ accessed. 
"Anonymous" shows the amount of memory that does not belong to any file.  Even

a mapping associated with a file may contain anonymous pages: when MAP_PRIVATE

and a page is modified, the file page is replaced by a private anonymous copy.

"LazyFree" shows the amount of memory which is marked by madvise(MADV_FREE).

The memory isn't freed immediately with madvise(). It's freed in memory

pressure if the memory is clean. Please note that the printed value might

be lower than the real value due to optimizations used in the current

implementation. If this is not desirable please file a bug report.

"AnonHugePages" shows the ammount of memory backed by transparent hugepage.

"ShmemPmdMapped" shows the ammount of shared (shmem/tmpfs) memory backed by

huge pages.

fs/proc/task_mmu.c

+7 −1
Original line number Diff line number Diff line
@@ -441,6 +441,7 @@ struct mem_size_stats { 
	unsigned long private_dirty;

	unsigned long referenced;

	unsigned long anonymous;

	unsigned long lazyfree;

	unsigned long anonymous_thp;

	unsigned long shmem_thp;

	unsigned long swap;
@@ -457,8 +458,11 @@ static void smaps_account(struct mem_size_stats *mss, struct page *page, 
	int i, nr = compound ? 1 << compound_order(page) : 1;

	unsigned long size = nr * PAGE_SIZE;



	if (PageAnon(page))

	if (PageAnon(page)) {

		mss->anonymous += size;

		if (!PageSwapBacked(page) && !dirty && !PageDirty(page))

			mss->lazyfree += size;

	}



	mss->resident += size;

	/* Accumulate the size in pages that have been accessed. */
@@ -771,6 +775,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) 
		   "Private_Dirty:  %8lu kB\n"

		   "Referenced:     %8lu kB\n"

		   "Anonymous:      %8lu kB\n"

		   "LazyFree:       %8lu kB\n"

		   "AnonHugePages:  %8lu kB\n"

		   "ShmemPmdMapped: %8lu kB\n"

		   "Shared_Hugetlb: %8lu kB\n"
@@ -789,6 +794,7 @@ static int show_smap(struct seq_file *m, void *v, int is_pid) 
		   mss.private_dirty >> 10,

		   mss.referenced >> 10,

		   mss.anonymous >> 10,

		   mss.lazyfree >> 10,

		   mss.anonymous_thp >> 10,

		   mss.shmem_thp >> 10,

		   mss.shared_hugetlb >> 10,