From: Joonsoo Kim <iamjoonsoo.kim@lge.com>
To: Tejun Heo <tj@kernel.org>
Cc: vdavydov.dev@gmail.com, cl@linux.com, penberg@kernel.org,
rientjes@google.com, akpm@linux-foundation.org, jsvana@fb.com,
hannes@cmpxchg.org, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, cgroups@vger.kernel.org, kernel-team@fb.com
Subject: Re: [PATCHSET v2] slab: make memcg slab destruction scalable
Date: Wed, 18 Jan 2017 16:54:48 +0900 [thread overview]
Message-ID: <20170118075448.GA1255@js1304-P5Q-DELUXE> (raw)
In-Reply-To: <20170117164913.GB28948@mtj.duckdns.org>
On Tue, Jan 17, 2017 at 08:49:13AM -0800, Tejun Heo wrote:
> Hello,
>
> On Tue, Jan 17, 2017 at 09:12:57AM +0900, Joonsoo Kim wrote:
> > Could you confirm that your series solves the problem that is reported
> > by Doug? It would be great if the result is mentioned to the patch
> > description.
> >
> > https://bugzilla.kernel.org/show_bug.cgi?id=172991
>
> So, that's an issue in the creation path which is already resolved by
> switching to an ordered workqueue (it'd probably be better to use
> per-cpu wq w/ @max_active == 1 tho). This patchset is about relesae
> path. slab_mutex contention would definitely go down with this but
> I don't think there's more connection to it than that.
That problem is caused by slow release path and then contention on the
slab_mutex. With an ordered workqueue, kworker would not be created a
lot but it can be possible that a lot of work items to create a new
cache for memcg is pending for a long time due to slow release path.
Your patchset replaces optimization for release path so it's better to
check that the work isn't pending for a long time in above workload.
Thanks.
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next prev parent reply other threads:[~2017-01-18 7:48 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-14 18:48 [PATCHSET v2] slab: make memcg slab destruction scalable Tejun Heo
2017-01-14 18:48 ` [PATCH 1/8] Revert "slub: move synchronize_sched out of slab_mutex on shrink" Tejun Heo
2017-01-14 18:48 ` [PATCH 2/8] slab: remove synchronous rcu_barrier() call in memcg cache release path Tejun Heo
2017-01-14 18:48 ` [PATCH 3/8] slab: reorganize memcg_cache_params Tejun Heo
2017-01-14 18:48 ` [PATCH 4/8] slab: link memcg kmem_caches on their associated memory cgroup Tejun Heo
2017-01-14 18:48 ` [PATCH 5/8] slab: implement slab_root_caches list Tejun Heo
2017-01-14 18:48 ` [PATCH 6/8] slab: introduce __kmemcg_cache_deactivate() Tejun Heo
2017-01-14 18:48 ` [PATCH 7/8] slab: remove synchronous synchronize_sched() from memcg cache deactivation path Tejun Heo
2017-01-17 0:26 ` Joonsoo Kim
2017-01-17 16:42 ` Tejun Heo
2017-01-14 18:48 ` [PATCH 8/8] slab: remove slub sysfs interface files early for empty memcg caches Tejun Heo
2017-01-17 0:12 ` [PATCHSET v2] slab: make memcg slab destruction scalable Joonsoo Kim
2017-01-17 16:49 ` Tejun Heo
2017-01-18 7:54 ` Joonsoo Kim [this message]
2017-01-18 21:01 ` Tejun Heo
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