All of lore.kernel.org
 help / color / mirror / Atom feed
From: Waiman Long <llong@redhat.com>
To: Roman Gushchin <guro@fb.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>,
	Michal Hocko <mhocko@kernel.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	linux-kernel@vger.kernel.org, cgroups@vger.kernel.org,
	linux-mm@kvack.org, Shakeel Butt <shakeelb@google.com>,
	Muchun Song <songmuchun@bytedance.com>
Subject: Re: [PATCH 2/3] mm, memcg: Remove obsolete memcg_free_kmem()
Date: Fri, 1 Oct 2021 22:03:05 -0400	[thread overview]
Message-ID: <b45fd235-a454-360e-4853-d41db3213e9d@redhat.com> (raw)
In-Reply-To: <YVehP18mCcsXmFy1@carbon.dhcp.thefacebook.com>

On 10/1/21 8:01 PM, Roman Gushchin wrote:
> On Fri, Oct 01, 2021 at 03:09:37PM -0400, Waiman Long wrote:
>> Since commit d648bcc7fe65 ("mm: kmem: make memcg_kmem_enabled()
>> irreversible"), the only thing memcg_free_kmem() does is to call
>> memcg_offline_kmem() when the memcg is still online. However,
>> memcg_offline_kmem() is only called from mem_cgroup_css_free() which
>> cannot be reached if the memcg hasn't been offlined first.
> Hm, is it true? What if online_css() fails?
I just realize that memcg_online_kmem() is called at css_create(). So 
yes, if css_online() fails (i.e. ENOMEM), we will need to do 
memcg_offline_kmem().
>> As this
>> function now serves no purpose, we should just remove it.
> It looks like we can just use memcg_offline_kmem() instead of
> memcg_free_kmem().

Right, memcg_free_kmem() isn't the right name for that. I agree that we 
should just change mem_cgroup_css_free() to call memcg_offline_kmem() 
directly. Will update the patch accordingly.

Thanks,
Longman


  reply	other threads:[~2021-10-02  2:03 UTC|newest]

Thread overview: 39+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-10-01 19:09 [PATCH 0/3] mm, memcg: Miscellaneous cleanups Waiman Long
2021-10-01 19:09 ` Waiman Long
2021-10-01 19:09 ` [PATCH 1/3] mm, memcg: Don't put offlined memcg into local stock Waiman Long
2021-10-01 19:09   ` Waiman Long
2021-10-01 21:17   ` kernel test robot
2021-10-01 21:17     ` kernel test robot
2021-10-01 21:17     ` kernel test robot
2021-10-01 23:06   ` kernel test robot
2021-10-01 23:06     ` kernel test robot
2021-10-01 23:06     ` kernel test robot
2021-10-01 23:51   ` Roman Gushchin
2021-10-01 23:51     ` Roman Gushchin
2021-10-02  1:54     ` Waiman Long
2021-10-02  1:54       ` Waiman Long
2022-01-31  3:55     ` Waiman Long
2022-01-31  3:55       ` Waiman Long
2022-01-31 17:01       ` Roman Gushchin
2022-01-31 17:01         ` Roman Gushchin
2022-01-31 17:09         ` Waiman Long
2022-01-31 17:15           ` Waiman Long
2022-01-31 17:19             ` Roman Gushchin
2022-01-31 17:19               ` Roman Gushchin
2022-01-31 17:25               ` Waiman Long
2022-01-31 17:25                 ` Waiman Long
2022-01-31 18:00                 ` Shakeel Butt
2022-01-31 18:00                   ` Shakeel Butt
2022-01-31 17:15           ` Roman Gushchin
2022-01-31 17:15             ` Roman Gushchin
2021-10-01 19:09 ` [PATCH 2/3] mm, memcg: Remove obsolete memcg_free_kmem() Waiman Long
2021-10-01 19:09   ` Waiman Long
2021-10-02  0:01   ` Roman Gushchin
2021-10-02  0:01     ` Roman Gushchin
2021-10-02  2:03     ` Waiman Long [this message]
2021-10-01 19:09 ` [PATCH 3/3] mm, memcg: Ensure valid memcg from objcg within a RCU critical section Waiman Long
2021-10-01 19:09   ` Waiman Long
2021-10-01 20:24   ` Shakeel Butt
2021-10-01 20:24     ` Shakeel Butt
2021-10-01 20:24     ` Shakeel Butt
2021-10-01 20:34     ` Waiman Long

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=b45fd235-a454-360e-4853-d41db3213e9d@redhat.com \
    --to=llong@redhat.com \
    --cc=akpm@linux-foundation.org \
    --cc=cgroups@vger.kernel.org \
    --cc=guro@fb.com \
    --cc=hannes@cmpxchg.org \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=mhocko@kernel.org \
    --cc=shakeelb@google.com \
    --cc=songmuchun@bytedance.com \
    --cc=vbabka@suse.cz \
    --cc=vdavydov.dev@gmail.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.