From: Shakeel Butt <shakeelb@google.com>
To: Jan Kara <jack@suse.cz>
Cc: Andrew Morton <akpm@linux-foundation.org>,
Michal Hocko <mhocko@kernel.org>,
Johannes Weiner <hannes@cmpxchg.org>,
Vladimir Davydov <vdavydov.dev@gmail.com>,
Jan Kara <jack@suse.com>, Greg Thelen <gthelen@google.com>,
Amir Goldstein <amir73il@gmail.com>, Roman Gushchin <guro@fb.com>,
Alexander Viro <viro@zeniv.linux.org.uk>,
LKML <linux-kernel@vger.kernel.org>,
Cgroups <cgroups@vger.kernel.org>,
linux-fsdevel <linux-fsdevel@vger.kernel.org>,
Linux MM <linux-mm@kvack.org>
Subject: Re: [PATCH 1/2] fs: fsnotify: account fsnotify metadata to kmemcg
Date: Thu, 28 Jun 2018 12:21:26 -0700 [thread overview]
Message-ID: <CALvZod5Fy7cUnqMvCqw8M52wm8+wBtGD-bhUibN=Uwdzb+5Kyw@mail.gmail.com> (raw)
In-Reply-To: <20180628100253.jscxkw2d6vfhnbo5@quack2.suse.cz>
On Thu, Jun 28, 2018 at 12:03 PM Jan Kara <jack@suse.cz> wrote:
>
> On Wed 27-06-18 12:12:49, Shakeel Butt wrote:
> > A lot of memory can be consumed by the events generated for the huge or
> > unlimited queues if there is either no or slow listener. This can cause
> > system level memory pressure or OOMs. So, it's better to account the
> > fsnotify kmem caches to the memcg of the listener.
> >
> > However the listener can be in a different memcg than the memcg of the
> > producer and these allocations happen in the context of the event
> > producer. This patch introduces remote memcg charging API which the
> > producer can use to charge the allocations to the memcg of the listener.
> >
> > There are seven fsnotify kmem caches and among them allocations from
> > dnotify_struct_cache, dnotify_mark_cache, fanotify_mark_cache and
> > inotify_inode_mark_cachep happens in the context of syscall from the
> > listener. So, SLAB_ACCOUNT is enough for these caches.
> >
> > The objects from fsnotify_mark_connector_cachep are not accounted as they
> > are small compared to the notification mark or events and it is unclear
> > whom to account connector to since it is shared by all events attached to
> > the inode.
> >
> > The allocations from the event caches happen in the context of the event
> > producer. For such caches we will need to remote charge the allocations
> > to the listener's memcg. Thus we save the memcg reference in the
> > fsnotify_group structure of the listener.
> >
> > This patch has also moved the members of fsnotify_group to keep the size
> > same, at least for 64 bit build, even with additional member by filling
> > the holes.
>
> ...
>
> > static int __init fanotify_user_setup(void)
> > {
> > - fanotify_mark_cache = KMEM_CACHE(fsnotify_mark, SLAB_PANIC);
> > + fanotify_mark_cache = KMEM_CACHE(fsnotify_mark,
> > + SLAB_PANIC|SLAB_ACCOUNT);
> > fanotify_event_cachep = KMEM_CACHE(fanotify_event_info, SLAB_PANIC);
> > if (IS_ENABLED(CONFIG_FANOTIFY_ACCESS_PERMISSIONS)) {
> > fanotify_perm_event_cachep =
>
> Why don't you setup also fanotify_event_cachep and
> fanotify_perm_event_cachep caches with SLAB_ACCOUNT and instead specify
> __GFP_ACCOUNT manually? Otherwise the patch looks good to me.
>
Hi Jan, IMHO having a visible __GFP_ACCOUNT along with
memalloc_use_memcg() makes the code more explicit and readable that we
want to targeted/remote memcg charging. However if you think
otherwise, I will replace __GFP_ACCOUNT with SLAB_ACCOUNT.
thanks,
Shakeel
next prev parent reply other threads:[~2018-06-28 19:21 UTC|newest]
Thread overview: 21+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-27 19:12 [PATCH v8 0/2] Directed kmem charging Shakeel Butt
2018-06-27 19:12 ` [PATCH 1/2] fs: fsnotify: account fsnotify metadata to kmemcg Shakeel Butt
2018-06-28 10:02 ` Jan Kara
2018-06-28 19:21 ` Shakeel Butt [this message]
2018-06-29 9:52 ` Michal Hocko
2018-06-29 17:44 ` Jan Kara
2018-07-02 21:54 ` [PATCH] fs-fsnotify-account-fsnotify-metadata-to-kmemcg.patch.cleanup Shakeel Butt
2018-07-02 21:56 ` Shakeel Butt
2018-06-27 19:12 ` [PATCH 2/2] fs, mm: account buffer_head to kmemcg Shakeel Butt
2018-07-02 22:02 ` [PATCH] fs-mm-account-buffer_head-to-kmemcg.patch.fix Shakeel Butt
2018-08-15 22:25 ` [PATCH v8 0/2] Directed kmem charging Andrew Morton
2018-08-17 13:04 ` Johannes Weiner
-- strict thread matches above, loose matches on Subject: below --
2018-06-25 23:06 [PATCH v7 " Shakeel Butt
2018-06-25 23:06 ` [PATCH 1/2] fs: fsnotify: account fsnotify metadata to kmemcg Shakeel Butt
2018-06-26 5:49 ` Amir Goldstein
2018-06-26 18:00 ` Shakeel Butt
2018-06-26 18:57 ` Johannes Weiner
2018-06-26 19:07 ` Shakeel Butt
2018-06-27 7:31 ` Jan Kara
2018-06-26 19:06 ` Johannes Weiner
2018-06-26 20:05 ` Shakeel Butt
2018-06-27 5:50 ` Amir Goldstein
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