From: Michal Hocko <mhocko@kernel.org>
To: Shakeel Butt <shakeelb@google.com>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Greg Thelen <gthelen@google.com>,
Andrew Morton <akpm@linux-foundation.org>,
Linux MM <linux-mm@kvack.org>,
linux-fsdevel@vger.kernel.org,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH] fs, mm: account filp and names caches to kmemcg
Date: Mon, 9 Oct 2017 08:24:26 +0200 [thread overview]
Message-ID: <20171009062426.hmqedtqz5hkmhnff@dhcp22.suse.cz> (raw)
In-Reply-To: <CALvZod7YN4JCG7Anm2FViyZ0-APYy+nxEd3nyxe5LT_P0FC9wg@mail.gmail.com>
On Fri 06-10-17 12:33:03, Shakeel Butt wrote:
> >> names_cachep = kmem_cache_create("names_cache", PATH_MAX, 0,
> >> - SLAB_HWCACHE_ALIGN|SLAB_PANIC, NULL);
> >> + SLAB_HWCACHE_ALIGN|SLAB_PANIC|SLAB_ACCOUNT, NULL);
> >
> > I might be wrong but isn't name cache only holding temporary objects
> > used for path resolution which are not stored anywhere?
> >
>
> Even though they're temporary, many containers can together use a
> significant amount of transient uncharged memory. We've seen machines
> with 100s of MiBs in names_cache.
Yes that might be possible but are we prepared for random ENOMEM from
vfs calls which need to allocate a temporary name?
>
> >> filp_cachep = kmem_cache_create("filp", sizeof(struct file), 0,
> >> - SLAB_HWCACHE_ALIGN | SLAB_PANIC, NULL);
> >> + SLAB_HWCACHE_ALIGN | SLAB_PANIC | SLAB_ACCOUNT, NULL);
> >> percpu_counter_init(&nr_files, 0, GFP_KERNEL);
> >> }
> >
> > Don't we have a limit for the maximum number of open files?
> >
>
> Yes, there is a system limit of maximum number of open files. However
> this limit is shared between different users on the system and one
> user can hog this resource. To cater that, we set the maximum limit
> very high and let the memory limit of each user limit the number of
> files they can open.
Similarly here. Are all syscalls allocating a fd prepared to return
ENOMEM?
--
Michal Hocko
SUSE Labs
next prev parent reply other threads:[~2017-10-09 6:24 UTC|newest]
Thread overview: 52+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-10-05 22:21 [PATCH] fs, mm: account filp and names caches to kmemcg Shakeel Butt
2017-10-06 7:59 ` Michal Hocko
2017-10-06 19:33 ` Shakeel Butt
2017-10-09 6:24 ` Michal Hocko [this message]
2017-10-09 17:52 ` Greg Thelen
2017-10-09 18:04 ` Michal Hocko
2017-10-09 18:17 ` Michal Hocko
2017-10-10 9:10 ` Michal Hocko
2017-10-10 22:21 ` Shakeel Butt
2017-10-11 9:09 ` Michal Hocko
2017-10-09 20:26 ` Johannes Weiner
2017-10-10 9:14 ` Michal Hocko
2017-10-10 14:17 ` Johannes Weiner
2017-10-10 14:24 ` Michal Hocko
2017-10-12 19:03 ` Johannes Weiner
2017-10-12 23:57 ` Greg Thelen
2017-10-13 6:51 ` Michal Hocko
2017-10-13 6:35 ` Michal Hocko
2017-10-13 7:00 ` Michal Hocko
2017-10-13 15:24 ` Michal Hocko
2017-10-24 12:18 ` Michal Hocko
2017-10-24 17:54 ` Johannes Weiner
2017-10-24 16:06 ` Johannes Weiner
2017-10-24 16:22 ` Michal Hocko
2017-10-24 17:23 ` Johannes Weiner
2017-10-24 17:55 ` Michal Hocko
2017-10-24 18:58 ` Johannes Weiner
2017-10-24 20:15 ` Michal Hocko
2017-10-25 6:51 ` Greg Thelen
2017-10-25 7:15 ` Michal Hocko
2017-10-25 13:11 ` Johannes Weiner
2017-10-25 14:12 ` Michal Hocko
2017-10-25 16:44 ` Johannes Weiner
2017-10-25 17:29 ` Michal Hocko
2017-10-25 18:11 ` Johannes Weiner
2017-10-25 19:00 ` Michal Hocko
2017-10-25 21:13 ` Johannes Weiner
2017-10-25 22:49 ` Greg Thelen
2017-10-26 7:49 ` Michal Hocko
2017-10-26 12:45 ` Tetsuo Handa
2017-10-26 14:31 ` Johannes Weiner
2017-10-26 19:56 ` Greg Thelen
2017-10-27 8:20 ` Michal Hocko
2017-10-27 20:50 ` Shakeel Butt
2017-10-30 8:29 ` Michal Hocko
2017-10-30 19:28 ` Shakeel Butt
2017-10-31 8:00 ` Michal Hocko
2017-10-31 16:49 ` Johannes Weiner
2017-10-31 18:50 ` Michal Hocko
2017-10-24 15:45 ` Johannes Weiner
2017-10-24 16:30 ` Michal Hocko
2017-10-10 23:32 ` Al Viro
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