From: Chris Down <chris@chrisdown.name>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>, Tejun Heo <tj@kernel.org>,
Roman Gushchin <guro@fb.com>, Michal Hocko <mhocko@kernel.org>,
linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
linux-mm@kvack.org, kernel-team@fb.com
Subject: [PATCH] docs: cgroup: mm: Document why inactive_X + active_X may not equal X
Date: Mon, 11 Nov 2019 14:49:58 +0000 [thread overview]
Message-ID: <20191111144958.GA11914@chrisdown.name> (raw)
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
Signed-off-by: Chris Down <chris@chrisdown.name>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Tejun Heo <tj@kernel.org>
Cc: Roman Gushchin <guro@fb.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: linux-kernel@vger.kernel.org
Cc: cgroups@vger.kernel.org
Cc: linux-mm@kvack.org
Cc: kernel-team@fb.com
---
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 0704552ed94f..0636bcb60b5a 100644
--- a/Documentation/admin-guide/cgroup-v2.rst
+++ b/Documentation/admin-guide/cgroup-v2.rst
@@ -1289,7 +1289,12 @@ 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
--
2.24.0
next reply other threads:[~2019-11-11 14:50 UTC|newest]
Thread overview: 2+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-11-11 14:49 Chris Down [this message]
2019-11-11 14:53 ` [PATCH] docs: cgroup: mm: Document why inactive_X + active_X may not equal X Michal Hocko
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