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authorRodrigo Freire <rfreire@redhat.com>2016-01-14 15:21:58 -0800
committerLinus Torvalds <torvalds@linux-foundation.org>2016-01-14 16:00:49 -0800
commit0bc126d460453736c0e03d9da7ae0e9d4fcf86b3 (patch)
tree93c98c4e2fe8cec166574fc188a03825fc60db3d /Documentation
parent6f754ba4cfcc044078d4836056ac45404e1b6e85 (diff)
Documentation/filesystems: describe the shared memory usage/accounting
The Shared Memory accounting support is present in Kernel since commit 4b02108ac1b3 ("mm: oom analysis: add shmem vmstat") and in userland free(1) since 2014. This patch updates the Documentation to reflect this change. Signed-off-by: Rodrigo Freire <rfreire@redhat.com> Acked-by: Vlastimil Babka <vbabka@suse.cz> Cc: Hugh Dickins <hughd@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'Documentation')
-rw-r--r--Documentation/filesystems/proc.txt2
-rw-r--r--Documentation/filesystems/tmpfs.txt8
2 files changed, 6 insertions, 4 deletions
diff --git a/Documentation/filesystems/proc.txt b/Documentation/filesystems/proc.txt
index ffcd49589ab5..e95aa1c6eadf 100644
--- a/Documentation/filesystems/proc.txt
+++ b/Documentation/filesystems/proc.txt
@@ -855,6 +855,7 @@ Dirty: 968 kB
Writeback: 0 kB
AnonPages: 861800 kB
Mapped: 280372 kB
+Shmem: 644 kB
Slab: 284364 kB
SReclaimable: 159856 kB
SUnreclaim: 124508 kB
@@ -911,6 +912,7 @@ MemAvailable: An estimate of how much memory is available for starting new
AnonPages: Non-file backed pages mapped into userspace page tables
AnonHugePages: Non-file backed huge pages mapped into userspace page tables
Mapped: files which have been mmaped, such as libraries
+ Shmem: Total memory used by shared memory (shmem) and tmpfs
Slab: in-kernel data structures cache
SReclaimable: Part of Slab, that might be reclaimed, such as caches
SUnreclaim: Part of Slab, that cannot be reclaimed on memory pressure
diff --git a/Documentation/filesystems/tmpfs.txt b/Documentation/filesystems/tmpfs.txt
index 98ef55124158..d392e1505f17 100644
--- a/Documentation/filesystems/tmpfs.txt
+++ b/Documentation/filesystems/tmpfs.txt
@@ -17,10 +17,10 @@ RAM, where you have to create an ordinary filesystem on top. Ramdisks
cannot swap and you do not have the possibility to resize them.
Since tmpfs lives completely in the page cache and on swap, all tmpfs
-pages currently in memory will show up as cached. It will not show up
-as shared or something like that. Further on you can check the actual
-RAM+swap use of a tmpfs instance with df(1) and du(1).
-
+pages will be shown as "Shmem" in /proc/meminfo and "Shared" in
+free(1). Notice that these counters also include shared memory
+(shmem, see ipcs(1)). The most reliable way to get the count is
+using df(1) and du(1).
tmpfs has the following uses: