* [PATCH] docs: cgroup: mm: Document why inactive_X + active_X may not equal X
@ 2019-11-11 14:49 Chris Down
2019-11-11 14:53 ` Michal Hocko
0 siblings, 1 reply; 2+ messages in thread
From: Chris Down @ 2019-11-11 14:49 UTC (permalink / raw)
To: Andrew Morton
Cc: Johannes Weiner, Tejun Heo, Roman Gushchin, Michal Hocko,
linux-kernel, cgroups, linux-mm, kernel-team
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
^ permalink raw reply related [flat|nested] 2+ messages in thread
* Re: [PATCH] docs: cgroup: mm: Document why inactive_X + active_X may not equal X
2019-11-11 14:49 [PATCH] docs: cgroup: mm: Document why inactive_X + active_X may not equal X Chris Down
@ 2019-11-11 14:53 ` Michal Hocko
0 siblings, 0 replies; 2+ messages in thread
From: Michal Hocko @ 2019-11-11 14:53 UTC (permalink / raw)
To: Chris Down
Cc: Andrew Morton, Johannes Weiner, Tejun Heo, Roman Gushchin,
linux-kernel, cgroups, linux-mm, kernel-team
On Mon 11-11-19 14:49:58, Chris Down wrote:
> 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
Acked-by: Michal Hocko <mhocko@suse.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
and anon will move to file list after MADV_FREE.
> + 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
--
Michal Hocko
SUSE Labs
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