From: Waiman Long <longman@redhat.com>
To: Roman Gushchin <guro@fb.com>
Cc: Christoph Lameter <cl@linux.com>,
Pekka Enberg <penberg@kernel.org>,
David Rientjes <rientjes@google.com>,
Joonsoo Kim <iamjoonsoo.kim@lge.com>,
Andrew Morton <akpm@linux-foundation.org>,
Alexander Viro <viro@zeniv.linux.org.uk>,
Jonathan Corbet <corbet@lwn.net>,
Luis Chamberlain <mcgrof@kernel.org>,
Kees Cook <keescook@chromium.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Michal Hocko <mhocko@kernel.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
"linux-doc@vger.kernel.org" <linux-doc@vger.kernel.org>,
"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
"cgroups@vger.kernel.org" <cgroups@vger.kernel.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
Shakeel Butt <shakeelb@google.com>,
Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 2/2] mm, slab: Extend vm/drop_caches to shrink kmem slabs
Date: Thu, 27 Jun 2019 17:31:58 -0400 [thread overview]
Message-ID: <73f18141-7e74-9630-06ff-ac8cf9688e6e@redhat.com> (raw)
In-Reply-To: <20190627212419.GA25233@tower.DHCP.thefacebook.com>
On 6/27/19 5:24 PM, Roman Gushchin wrote:
>>> 2) what's your long-term vision here? do you think that we need to shrink
>>> kmem_caches periodically, depending on memory pressure? how a user
>>> will use this new sysctl?
>> Shrinking the kmem caches under extreme memory pressure can be one way
>> to free up extra pages, but the effect will probably be temporary.
>>> What's the problem you're trying to solve in general?
>> At least for the slub allocator, shrinking the caches allow the number
>> of active objects reported in slabinfo to be more accurate. In addition,
>> this allow to know the real slab memory consumption. I have been working
>> on a BZ about continuous memory leaks with a container based workloads.
>> The ability to shrink caches allow us to get a more accurate memory
>> consumption picture. Another alternative is to turn on slub_debug which
>> will then disables all the per-cpu slabs.
> I see... I agree with Michal here, that extending drop_caches sysctl isn't
> the best idea. Isn't it possible to achieve the same effect using slub sysfs?
Yes, using the slub sysfs interface can be a possible alternative.
Cheers,
Longman
next prev parent reply other threads:[~2019-06-27 21:32 UTC|newest]
Thread overview: 19+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-24 17:42 [PATCH 0/2] mm, slab: Extend vm/drop_caches to shrink kmem slabs Waiman Long
2019-06-24 17:42 ` [PATCH 1/2] mm, memcontrol: Add memcg_iterate_all() Waiman Long
2019-06-27 15:07 ` Michal Hocko
2019-06-27 21:03 ` Waiman Long
2019-06-28 7:10 ` Michal Hocko
2019-06-24 17:42 ` [PATCH 2/2] mm, slab: Extend vm/drop_caches to shrink kmem slabs Waiman Long
2019-06-26 20:19 ` Roman Gushchin
2019-06-27 20:57 ` Waiman Long
2019-06-27 21:24 ` Roman Gushchin
2019-06-27 21:31 ` Waiman Long [this message]
2019-06-28 15:32 ` Christopher Lameter
2019-06-28 16:33 ` Roman Gushchin
2019-06-28 17:16 ` Yang Shi
2019-06-28 17:30 ` Roman Gushchin
2019-06-27 21:25 ` Luis Chamberlain
2019-06-27 15:15 ` Michal Hocko
2019-06-27 21:16 ` Waiman Long
2019-06-28 7:31 ` Michal Hocko
2019-07-02 18:41 ` Waiman Long
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