Re: [PATCH] memcg: Add kmem.slabinfo to v2 for debugging purpose

From: Waiman Long
Date: Thu Jun 27 2019 - 09:48:00 EST

On 6/26/19 6:25 PM, Andrew Morton wrote:
> On Wed, 26 Jun 2019 12:56:14 -0400 Waiman Long <longman@xxxxxxxxxx> wrote:
>> With memory cgroup v1, there is a kmem.slabinfo file that can be
>> used to view what slabs are allocated to the memory cgroup. There
>> is currently no such equivalent in memory cgroup v2. This file can
>> be useful for debugging purpose.
>> This patch adds an equivalent kmem.slabinfo to v2 with the caveat that
>> this file will only show up as ".__DEBUG__.memory.kmem.slabinfo" when the
>> "cgroup_debug" parameter is specified in the kernel boot command line.
>> This is to avoid cluttering the cgroup v2 interface with files that
>> are seldom used by end users.
>> ...
>> mm/memcontrol.c | 16 ++++++++++++++++
>> 1 file changed, 16 insertions(+)
> A change to the kernel's user interface triggers a change to the
> kernel's user interface documentation. This should be automatic by
> now :(
We don't usually document debugging only files as they are subject to
change with no stability guarantee. That is the point of marking it for
debugging instead of a regular file that we need to support forever.