From 1603c8d1b1fbfbc20dcb363543b690de862849c0 Mon Sep 17 00:00:00 2001 From: Chris Down Date: Sat, 30 Nov 2019 17:50:19 -0800 Subject: [PATCH] Documentation/admin-guide/cgroup-v2.rst: document why inactive_X + active_X may not equal X This has confused a significant number of people using cgroups inside Facebook, and some of those outside as well judging by posts like this[0] (although it's not a problem unique to cgroup v2). If shmem handling in particular becomes more coherent at some point in the future -- although that seems unlikely now -- we can change the wording here. [0]: https://unix.stackexchange.com/q/525092/10762 Link: http://lkml.kernel.org/r/20191111144958.GA11914@chrisdown.name Signed-off-by: Chris Down Acked-by: Michal Hocko Cc: Johannes Weiner Cc: Tejun Heo Cc: Roman Gushchin Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- Documentation/admin-guide/cgroup-v2.rst | 7 ++++++- 1 file changed, 6 insertions(+), 1 deletion(-) diff --git a/Documentation/admin-guide/cgroup-v2.rst b/Documentation/admin-guide/cgroup-v2.rst index 007ba86aef78..6d13f2de6d69 100644 --- a/Documentation/admin-guide/cgroup-v2.rst +++ b/Documentation/admin-guide/cgroup-v2.rst @@ -1288,7 +1288,12 @@ PAGE_SIZE multiple when read back. inactive_anon, active_anon, inactive_file, active_file, unevictable Amount of memory, swap-backed and filesystem-backed, on the internal memory management lists used by the - page reclaim algorithm + page reclaim algorithm. + + As these represent internal list state (eg. shmem pages are on anon + memory management lists), inactive_foo + active_foo may not be equal to + the value for the foo counter, since the foo counter is type-based, not + list-based. slab_reclaimable Part of "slab" that might be reclaimed, such as -- 2.30.2