| Message ID | 20191111144958.GA11914@chrisdown.name (mailing list archive) |
|---|---|
| State | New, archived |
| Headers | show |
| Series | docs: cgroup: mm: Document why inactive_X + active_X may not equal X | expand |
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
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
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(-)