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From: Li Zefan <lizefan@huawei.com>
To: Tejun Heo <tj@kernel.org>
Cc: <cgroups@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
	<hannes@cmpxchg.org>
Subject: Re: [PATCHSET cgroup/for-3.16] cgroup: iterate cgroup_subsys_states directly
Date: Wed, 14 May 2014 12:21:25 +0800	[thread overview]
Message-ID: <5372EF45.8060701@huawei.com> (raw)
In-Reply-To: <1399671091-23867-1-git-send-email-tj@kernel.org>

Hi Tejun,

On 2014/5/10 5:31, Tejun Heo wrote:
> Hello,
> 
> Currently, while csses (cgroup_subsys_states) have ->parent linkage
> too, only cgroups form full tree through their ->children and
> ->sibling fields and css iterations naturally is implemented by
> iterating cgroups and then dereferencing the css for the specified
> subsystem.
> 
> There are now use cases where controllers need to iterate through
> csses regardless of their online state as long as they have positive

What use cases are we talking about here?

> reference.  This can't easily be achieved by iterating cgroups because
> its css pointer array needs to be cleared on offline and there may be
> multiple dying csses for a cgroup for the same subsystem and there's
> only one pointer per cgroup-subsystem pair.
> 


  parent reply	other threads:[~2014-05-14  4:21 UTC|newest]

Thread overview: 48+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2014-05-09 21:31 [PATCHSET cgroup/for-3.16] cgroup: iterate cgroup_subsys_states directly Tejun Heo
2014-05-09 21:31 ` [PATCH 01/14] cgroup: remove css_parent() Tejun Heo
2014-05-11  1:47   ` David Miller
2014-05-11 13:02   ` Neil Horman
2014-05-12 13:16   ` Michal Hocko
2014-05-13 18:50   ` [PATCH v2 " Tejun Heo
2014-05-09 21:31 ` [PATCH 02/14] cgroup: remove pointless has tasks/children test from mem_cgroup_force_empty() Tejun Heo
2014-05-12 14:53   ` Michal Hocko
2014-05-12 14:58     ` [PATCH] memcg: deprecate memory.force_empty knob Michal Hocko
2014-05-12 15:00       ` Tejun Heo
2014-05-12 15:20         ` Michal Hocko
2014-05-12 15:25           ` Tejun Heo
2014-05-12 15:34             ` Michal Hocko
2014-05-13 13:16               ` Johannes Weiner
2014-05-13 15:09                 ` Michal Hocko
2014-05-12 14:59     ` [PATCH 02/14] cgroup: remove pointless has tasks/children test from mem_cgroup_force_empty() Tejun Heo
2014-05-12 15:21       ` Michal Hocko
2014-05-13 13:10     ` Johannes Weiner
2014-05-13 16:46     ` Tejun Heo
2014-05-13 18:51     ` [PATCH UPDATED 02/14] memcg: remove " Tejun Heo
2014-05-09 21:31 ` [PATCH 03/14] memcg: update memcg_has_children() to use css_next_child() Tejun Heo
2014-05-12 15:18   ` Michal Hocko
2014-05-13 16:53   ` [PATCH v2 " Tejun Heo
2014-05-09 21:31 ` [PATCH 04/14] device_cgroup: remove direct access to cgroup->children Tejun Heo
2014-05-13 12:56   ` Aristeu Rozanski
2014-05-14 12:52   ` Serge E. Hallyn
2014-05-09 21:31 ` [PATCH 05/14] cgroup: remove cgroup->parent Tejun Heo
2014-05-09 21:31 ` [PATCH 06/14] cgroup: move cgroup->sibling and ->children into cgroup_subsys_state Tejun Heo
2014-05-09 21:31 ` [PATCH 07/14] cgroup: link all cgroup_subsys_states in their sibling lists Tejun Heo
2014-05-09 21:31 ` [PATCH 08/14] cgroup: move cgroup->serial_nr into cgroup_subsys_state Tejun Heo
2014-05-09 21:31 ` [PATCH 09/14] cgroup: introduce CSS_RELEASED and reduce css iteration fallback window Tejun Heo
2014-05-16 16:07   ` [PATCH v2 " Tejun Heo
2014-05-09 21:31 ` [PATCH 10/14] cgroup: iterate cgroup_subsys_states directly Tejun Heo
2014-05-09 21:31 ` [PATCH 11/14] cgroup: use CSS_ONLINE instead of CGRP_DEAD Tejun Heo
2014-05-09 21:31 ` [PATCH 12/14] cgroup: convert cgroup_has_live_children() into css_has_online_children() Tejun Heo
2014-05-09 21:31 ` [PATCH 13/14] device_cgroup: use css_has_online_children() instead of has_children() Tejun Heo
2014-05-13 12:56   ` Aristeu Rozanski
2014-05-14 12:53   ` Serge E. Hallyn
2014-05-09 21:31 ` [PATCH 14/14] cgroup: implement css_tryget() Tejun Heo
2014-05-11  4:54   ` Johannes Weiner
2014-05-11 12:38     ` Tejun Heo
2014-05-16 16:07   ` [PATCH v2 " Tejun Heo
2014-05-13 16:59 ` [PATCHSET cgroup/for-3.16] cgroup: iterate cgroup_subsys_states directly Tejun Heo
2014-05-14  4:21 ` Li Zefan [this message]
2014-05-14 13:07   ` Tejun Heo
2014-05-16  1:28     ` Li Zefan
2014-05-16  1:29 ` Li Zefan
2014-05-16 16:08 ` Tejun Heo

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