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
WARNING: multiple messages have this Message-ID (diff)
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
--
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>
next prev parent reply other threads:[~2017-10-09 6:24 UTC|newest]
Thread overview: 104+ 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
2017-10-05 22:21 ` Shakeel Butt
2017-10-06 7:59 ` Michal Hocko
2017-10-06 7:59 ` Michal Hocko
2017-10-06 19:33 ` Shakeel Butt
2017-10-06 19:33 ` Shakeel Butt
2017-10-09 6:24 ` Michal Hocko [this message]
2017-10-09 6:24 ` Michal Hocko
2017-10-09 17:52 ` Greg Thelen
2017-10-09 17:52 ` Greg Thelen
2017-10-09 18:04 ` Michal Hocko
2017-10-09 18:04 ` Michal Hocko
2017-10-09 18:17 ` Michal Hocko
2017-10-09 18:17 ` Michal Hocko
2017-10-10 9:10 ` Michal Hocko
2017-10-10 9:10 ` Michal Hocko
2017-10-10 22:21 ` Shakeel Butt
2017-10-10 22:21 ` Shakeel Butt
2017-10-11 9:09 ` Michal Hocko
2017-10-11 9:09 ` Michal Hocko
2017-10-09 20:26 ` Johannes Weiner
2017-10-09 20:26 ` Johannes Weiner
2017-10-10 9:14 ` Michal Hocko
2017-10-10 9:14 ` Michal Hocko
2017-10-10 14:17 ` Johannes Weiner
2017-10-10 14:17 ` Johannes Weiner
2017-10-10 14:24 ` Michal Hocko
2017-10-10 14:24 ` Michal Hocko
2017-10-12 19:03 ` Johannes Weiner
2017-10-12 19:03 ` Johannes Weiner
2017-10-12 23:57 ` Greg Thelen
2017-10-12 23:57 ` Greg Thelen
2017-10-13 6:51 ` Michal Hocko
2017-10-13 6:51 ` Michal Hocko
2017-10-13 6:35 ` Michal Hocko
2017-10-13 6:35 ` Michal Hocko
2017-10-13 7:00 ` Michal Hocko
2017-10-13 7:00 ` Michal Hocko
2017-10-13 15:24 ` Michal Hocko
2017-10-13 15:24 ` Michal Hocko
2017-10-24 12:18 ` Michal Hocko
2017-10-24 12:18 ` Michal Hocko
2017-10-24 17:54 ` Johannes Weiner
2017-10-24 17:54 ` Johannes Weiner
2017-10-24 16:06 ` Johannes Weiner
2017-10-24 16:06 ` Johannes Weiner
2017-10-24 16:22 ` Michal Hocko
2017-10-24 16:22 ` Michal Hocko
2017-10-24 17:23 ` Johannes Weiner
2017-10-24 17:23 ` Johannes Weiner
2017-10-24 17:55 ` Michal Hocko
2017-10-24 17:55 ` Michal Hocko
2017-10-24 18:58 ` Johannes Weiner
2017-10-24 18:58 ` Johannes Weiner
2017-10-24 20:15 ` Michal Hocko
2017-10-24 20:15 ` Michal Hocko
2017-10-25 6:51 ` Greg Thelen
2017-10-25 6:51 ` Greg Thelen
2017-10-25 7:15 ` Michal Hocko
2017-10-25 7:15 ` Michal Hocko
2017-10-25 13:11 ` Johannes Weiner
2017-10-25 13:11 ` Johannes Weiner
2017-10-25 14:12 ` Michal Hocko
2017-10-25 14:12 ` Michal Hocko
2017-10-25 16:44 ` Johannes Weiner
2017-10-25 16:44 ` Johannes Weiner
2017-10-25 17:29 ` Michal Hocko
2017-10-25 17:29 ` Michal Hocko
2017-10-25 18:11 ` Johannes Weiner
2017-10-25 18:11 ` Johannes Weiner
2017-10-25 19:00 ` Michal Hocko
2017-10-25 19:00 ` Michal Hocko
2017-10-25 21:13 ` Johannes Weiner
2017-10-25 21:13 ` Johannes Weiner
2017-10-25 22:49 ` Greg Thelen
2017-10-25 22:49 ` Greg Thelen
2017-10-26 7:49 ` Michal Hocko
2017-10-26 7:49 ` Michal Hocko
2017-10-26 12:45 ` Tetsuo Handa
2017-10-26 12:45 ` Tetsuo Handa
2017-10-26 14:31 ` Johannes Weiner
2017-10-26 14:31 ` Johannes Weiner
2017-10-26 19:56 ` Greg Thelen
2017-10-26 19:56 ` Greg Thelen
2017-10-27 8:20 ` Michal Hocko
2017-10-27 8:20 ` Michal Hocko
2017-10-27 20:50 ` Shakeel Butt
2017-10-27 20:50 ` Shakeel Butt
2017-10-30 8:29 ` Michal Hocko
2017-10-30 8:29 ` Michal Hocko
2017-10-30 19:28 ` Shakeel Butt
2017-10-30 19:28 ` Shakeel Butt
2017-10-31 8:00 ` Michal Hocko
2017-10-31 8:00 ` Michal Hocko
2017-10-31 16:49 ` Johannes Weiner
2017-10-31 16:49 ` Johannes Weiner
2017-10-31 18:50 ` Michal Hocko
2017-10-31 18:50 ` Michal Hocko
2017-10-24 15:45 ` Johannes Weiner
2017-10-24 15:45 ` Johannes Weiner
2017-10-24 16:30 ` Michal Hocko
2017-10-24 16:30 ` Michal Hocko
2017-10-10 23:32 ` Al Viro
2017-10-10 23:32 ` Al Viro
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=20171009062426.hmqedtqz5hkmhnff@dhcp22.suse.cz \
--to=mhocko@kernel.org \
--cc=akpm@linux-foundation.org \
--cc=gthelen@google.com \
--cc=linux-fsdevel@vger.kernel.org \
--cc=linux-kernel@vger.kernel.org \
--cc=linux-mm@kvack.org \
--cc=shakeelb@google.com \
--cc=vdavydov.dev@gmail.com \
--cc=viro@zeniv.linux.org.uk \
/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.