From 0bc126d460453736c0e03d9da7ae0e9d4fcf86b3 Mon Sep 17 00:00:00 2001 From: Rodrigo Freire Date: Thu, 14 Jan 2016 15:21:58 -0800 Subject: [PATCH] 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 Acked-by: Vlastimil Babka Cc: Hugh Dickins Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/filesystems/proc.txt | 2 ++ Documentation/filesystems/tmpfs.txt | 8 ++++---- 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: -- 2.30.2