From: Glauber Costa <glommer-bzQdu9zFT3WakBO8gow8eQ@public•gmane.org>
To: Neil Horman <nhorman-2XuSBdqkA4R54TAoqtyWWQ@public•gmane.org>
Cc: Daniel Wagner <wagi-kQCPcA+X3s7YtjvyW6yDsg@public•gmane.org>,
<netdev-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
<cgroups-u79uwXL29TY76Z2rM5mHXA@public•gmane.org>,
Daniel Wagner
<daniel.wagner-98C5kh4wR6ohFhg+JK9F0w@public•gmane.org>,
"David S. Miller" <davem-fT/PcQaiUtIeIZ0/mPfg9Q@public•gmane.org>,
Gao feng <gaofeng-BthXqXjhjHXQFUHtdCDX3A@public•gmane.org>,
Jamal Hadi Salim <jhs-jkUAjuhPggJWk0Htik3J/w@public•gmane.org>,
John Fastabend
<john.r.fastabend-ral2JQCrhuEAvxtiuMwx3w@public•gmane.org>,
Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public•gmane.org>,
Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public•gmane.org>
Subject: Re: [PATCH v1 3/5] cgroup: Protect access to task_cls_classid() when built as module
Date: Tue, 21 Aug 2012 13:12:33 +0400 [thread overview]
Message-ID: <50335101.5030109@parallels.com> (raw)
In-Reply-To: <20120820170342.GC1734-B26myB8xz7F8NnZeBjwnZQMhkBWG/bsMQH7oEaQurus@public.gmane.org>
On 08/20/2012 09:03 PM, Neil Horman wrote:
>>> 2) Keep a separate internal counter to track the number of cgroup instances
>>> > > so that you only inc the static key on the first create and dec it on the last
>>> > > delete.
>> >
>> > If I got you right, than this would not be different then direclty using
>> > static_key_slow_[inc|dec].
>> >
> As long as a cgroup subsystems ->destroy method is only called when the
> subsystem is being removed, then I think thats correct. I'm not 100% sure thats
> the case though.
>
THAT is correct, but not the call itself. ->destroy() is called with the
cgroup_lock held, and there is a lockdep dependency created by cpuset
that prevents the cpu_hotplug lock, taken by static branch updates, to
be taken inside cgroup_lock.
So unless cpuset is fixed - which is a major work, we can't do
static_branch updates while holding the cgroup_lock.
next prev parent reply other threads:[~2012-08-21 9:12 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-08-17 14:58 [PATCH v1 0/5] cgroup: Assign subsystem IDs during compile time Daniel Wagner
[not found] ` <1345215494-9181-1-git-send-email-wagi-kQCPcA+X3s7YtjvyW6yDsg@public.gmane.org>
2012-08-17 14:58 ` [PATCH v1 1/5] cgroup: Use empty task_cls_classid() when !CONFIG_NET_CLS(_MODULE) Daniel Wagner
2012-08-17 14:58 ` [PATCH v1 2/5] cgroup: Move sock_update_classid() decleration to cls_cgroup.h Daniel Wagner
2012-08-17 14:58 ` [PATCH v1 3/5] cgroup: Protect access to task_cls_classid() when built as module Daniel Wagner
[not found] ` <1345215494-9181-4-git-send-email-wagi-kQCPcA+X3s7YtjvyW6yDsg@public.gmane.org>
2012-08-17 18:28 ` Neil Horman
2012-08-20 0:59 ` Li Zefan
[not found] ` <50318BF9.2080803-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2012-08-20 11:08 ` Neil Horman
[not found] ` <20120817182855.GA11607-B26myB8xz7F8NnZeBjwnZQMhkBWG/bsMQH7oEaQurus@public.gmane.org>
2012-08-20 11:29 ` Daniel Wagner
[not found] ` <20120820112938.GA22415-rjQKm2AMs/APuY3F5OKgMy7zKzJi9e1+kcYEyfhdaNw@public.gmane.org>
2012-08-20 11:33 ` Glauber Costa
2012-08-20 17:03 ` Neil Horman
[not found] ` <20120820170342.GC1734-B26myB8xz7F8NnZeBjwnZQMhkBWG/bsMQH7oEaQurus@public.gmane.org>
2012-08-21 9:12 ` Glauber Costa [this message]
[not found] ` <50335101.5030109-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-08-23 9:12 ` Daniel Wagner
[not found] ` <5035F3FC.202-kQCPcA+X3s7YtjvyW6yDsg@public.gmane.org>
2012-08-23 9:12 ` Glauber Costa
2012-08-17 14:58 ` [PATCH v1 4/5] cgroup: Protect access to task_netprioidx() " Daniel Wagner
2012-08-17 14:58 ` [PATCH v1 5/5] cgroup: Assign subsystem IDs during compile time Daniel Wagner
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