From: Vladimir Davydov <vdavydov@tarantool.org>
To: Tejun Heo <tj@kernel.org>
Cc: cl@linux.com, penberg@kernel.org, rientjes@google.com,
iamjoonsoo.kim@lge.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: [PATCH 2/9] slab: remove synchronous rcu_barrier() call in memcg cache release path
Date: Sat, 14 Jan 2017 16:19:39 +0300 [thread overview]
Message-ID: <20170114131939.GA2668@esperanza> (raw)
In-Reply-To: <20170114055449.11044-3-tj@kernel.org>
Hello Tejun,
Thanks a lot for looking into this issue as it seems to affect a lot of
users!
On Sat, Jan 14, 2017 at 12:54:42AM -0500, Tejun Heo wrote:
> This patch updates the cache release path so that it simply uses
> call_rcu() instead of the synchronous rcu_barrier() + custom batching.
> This doesn't cost more while being logically simpler and way more
> scalable.
The point of rcu_barrier() is to wait until all rcu calls freeing slabs
from the cache being destroyed are over (rcu_free_slab, kmem_rcu_free).
I'm not sure if call_rcu() guarantees that for all rcu implementations
too. If it did, why would we need rcu_barrier() at all?
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next prev parent reply other threads:[~2017-01-14 13:19 UTC|newest]
Thread overview: 26+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-14 5:54 [PATCHSET] slab: make memcg slab destruction scalable Tejun Heo
2017-01-14 5:54 ` [PATCH 1/9] Revert "slub: move synchronize_sched out of slab_mutex on shrink" Tejun Heo
2017-01-14 5:54 ` [PATCH 2/9] slab: remove synchronous rcu_barrier() call in memcg cache release path Tejun Heo
2017-01-14 13:19 ` Vladimir Davydov [this message]
2017-01-14 15:19 ` Tejun Heo
[not found] ` <20170114151921.GA32693-qYNAdHglDFBN0TnZuCh8vA@public.gmane.org>
2017-01-17 0:07 ` Joonsoo Kim
2017-01-17 16:37 ` Tejun Heo
2017-01-17 17:02 ` Tejun Heo
2017-01-14 5:54 ` [PATCH 3/9] slab: simplify shutdown_memcg_caches() Tejun Heo
2017-01-14 13:27 ` Vladimir Davydov
2017-01-14 15:38 ` Tejun Heo
2017-01-14 15:53 ` Tejun Heo
2017-01-14 5:54 ` [PATCH 4/9] slab: reorganize memcg_cache_params Tejun Heo
2017-01-14 13:30 ` Vladimir Davydov
2017-01-14 5:54 ` [PATCH 5/9] slab: link memcg kmem_caches on their associated memory cgroup Tejun Heo
2017-01-14 13:33 ` Vladimir Davydov
2017-01-14 5:54 ` [PATCH 6/9] slab: don't put memcg caches on slab_caches list Tejun Heo
2017-01-14 13:39 ` Vladimir Davydov
2017-01-14 15:39 ` Tejun Heo
2017-01-14 5:54 ` [PATCH 7/9] slab: introduce __kmemcg_cache_deactivate() Tejun Heo
2017-01-14 13:42 ` Vladimir Davydov
2017-01-14 15:39 ` Tejun Heo
2017-01-14 5:54 ` [PATCH 8/9] slab: remove synchronous synchronize_sched() from memcg cache deactivation path Tejun Heo
[not found] ` <20170114055449.11044-9-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2017-01-14 13:57 ` Vladimir Davydov
2017-01-14 5:54 ` [PATCH 9/9] slab: remove slub sysfs interface files early for empty memcg caches Tejun Heo
2017-01-14 14:00 ` Vladimir Davydov
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