All of lore.kernel.org
 help / color / mirror / Atom feed
From: Michal Hocko <mhocko@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Tejun Heo <tj@kernel.org>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH] mm: memcontrol: do not recurse in direct reclaim
Date: Tue, 25 Oct 2016 17:07:59 +0200	[thread overview]
Message-ID: <20161025150758.GN31137@dhcp22.suse.cz> (raw)
In-Reply-To: <20161025150142.GA31081@cmpxchg.org>

On Tue 25-10-16 11:01:42, Johannes Weiner wrote:
> On Tue, Oct 25, 2016 at 04:45:44PM +0200, Michal Hocko wrote:
> > On Tue 25-10-16 10:10:50, Johannes Weiner wrote:
> > > Like other direct reclaimers, mark tasks in memcg reclaim PF_MEMALLOC
> > > to avoid recursing into any other form of direct reclaim. Then let
> > > recursive charges from PF_MEMALLOC contexts bypass the cgroup limit.
> > 
> > Should we mark this for stable (up to 4.5) which changed the out-out to
> > opt-in?
> 
> Yes, good point.
> 
> Internally, we're pulling it into our 4.6 tree as well. The commit
> that fixes the particular bug we encountered in btrfs is a9bb7e620efd
> ("memcg: only account kmem allocations marked as __GFP_ACCOUNT") in
> 4.5+, so you could argue that we don't need the backport in kernels
> with this commit. And I'm not aware of other manifestations of this
> problem. But the unbounded recursion hole is still there, technically,
> so we might just want to put it into all stable kernels and be safe.
> 
> So either
> 
> Cc: <stable@vger.kernel.org>	# up to and including 4.5

As the patch was released in 4.5 it shouldn't be needed in 4.5 stable
tree but

> or, and I'm leaning toward that, simply
> 
> Cc: <stable@vger.kernel.org>

this sounds less confusing I guess.

-- 
Michal Hocko
SUSE Labs

WARNING: multiple messages have this Message-ID (diff)
From: Michal Hocko <mhocko@kernel.org>
To: Johannes Weiner <hannes@cmpxchg.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
	Vladimir Davydov <vdavydov.dev@gmail.com>,
	Tejun Heo <tj@kernel.org>,
	linux-mm@kvack.org, cgroups@vger.kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCH] mm: memcontrol: do not recurse in direct reclaim
Date: Tue, 25 Oct 2016 17:07:59 +0200	[thread overview]
Message-ID: <20161025150758.GN31137@dhcp22.suse.cz> (raw)
In-Reply-To: <20161025150142.GA31081@cmpxchg.org>

On Tue 25-10-16 11:01:42, Johannes Weiner wrote:
> On Tue, Oct 25, 2016 at 04:45:44PM +0200, Michal Hocko wrote:
> > On Tue 25-10-16 10:10:50, Johannes Weiner wrote:
> > > Like other direct reclaimers, mark tasks in memcg reclaim PF_MEMALLOC
> > > to avoid recursing into any other form of direct reclaim. Then let
> > > recursive charges from PF_MEMALLOC contexts bypass the cgroup limit.
> > 
> > Should we mark this for stable (up to 4.5) which changed the out-out to
> > opt-in?
> 
> Yes, good point.
> 
> Internally, we're pulling it into our 4.6 tree as well. The commit
> that fixes the particular bug we encountered in btrfs is a9bb7e620efd
> ("memcg: only account kmem allocations marked as __GFP_ACCOUNT") in
> 4.5+, so you could argue that we don't need the backport in kernels
> with this commit. And I'm not aware of other manifestations of this
> problem. But the unbounded recursion hole is still there, technically,
> so we might just want to put it into all stable kernels and be safe.
> 
> So either
> 
> Cc: <stable@vger.kernel.org>	# up to and including 4.5

As the patch was released in 4.5 it shouldn't be needed in 4.5 stable
tree but

> or, and I'm leaning toward that, simply
> 
> Cc: <stable@vger.kernel.org>

this sounds less confusing I guess.

-- 
Michal Hocko
SUSE Labs

--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@kvack.org.  For more info on Linux MM,
see: http://www.linux-mm.org/ .
Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>

  reply	other threads:[~2016-10-25 15:08 UTC|newest]

Thread overview: 13+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-10-24 20:30 [PATCH] mm: memcontrol: do not recurse in direct reclaim Johannes Weiner
2016-10-24 20:30 ` Johannes Weiner
2016-10-25  9:07 ` Michal Hocko
2016-10-25  9:07   ` Michal Hocko
2016-10-25 14:10   ` Johannes Weiner
2016-10-25 14:10     ` Johannes Weiner
2016-10-25 14:10     ` Johannes Weiner
2016-10-25 14:45     ` Michal Hocko
2016-10-25 14:45       ` Michal Hocko
2016-10-25 15:01       ` Johannes Weiner
2016-10-25 15:01         ` Johannes Weiner
2016-10-25 15:07         ` Michal Hocko [this message]
2016-10-25 15:07           ` Michal Hocko

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=20161025150758.GN31137@dhcp22.suse.cz \
    --to=mhocko@kernel.org \
    --cc=akpm@linux-foundation.org \
    --cc=cgroups@vger.kernel.org \
    --cc=hannes@cmpxchg.org \
    --cc=kernel-team@fb.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=linux-mm@kvack.org \
    --cc=tj@kernel.org \
    --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.