From: Stephen Warren <swarren@wwwdotorg.org>
To: Tejun Heo <tj@kernel.org>, lizefan@huawei.com
Cc: cgroups@vger.kernel.org, linux-kernel@vger.kernel.org,
"linux-tegra@vger.kernel.org" <linux-tegra@vger.kernel.org>,
ARM kernel mailing list <linux-arm-kernel@lists.infradead.org>
Subject: Re: [PATCH 9/9] cgroup: use cgroup->self.refcnt for cgroup refcnting
Date: Thu, 15 May 2014 13:07:14 -0600 [thread overview]
Message-ID: <53751062.2050401@wwwdotorg.org> (raw)
In-Reply-To: <1399670015-23463-10-git-send-email-tj@kernel.org>
On 05/09/2014 03:13 PM, Tejun Heo wrote:
> Currently cgroup implements refcnting separately using atomic_t
> cgroup->refcnt. The destruction paths of cgroup and css are rather
> complex and bear a lot of similiarities including the use of RCU and
> bouncing to a work item.
>
> This patch makes cgroup use the refcnt of self css for refcnting
> instead of using its own. This makes cgroup refcnting use css's
> percpu refcnt and share the destruction mechanism.
>...
In next-20150515, this patch causes silent boot failures on NVIDIA Tegra
ARM systems. There isn't even any earlyprintk. Reverting this one patch
solves this.
I was a bit surprised that cgroups would cause such an issue, but
looking at a normal kernel boot, I guess cgroup does get initialized
very early:
Uncompressing Linux... done, booting the kernel.
[ 0.000000] Booting Linux on physical CPU 0x0
[ 0.000000] Initializing cgroup subsys cpu
[ 0.000000] Initializing cgroup subsys cpuacct
Anyway, I'll try to track down what the problem is, but if someone
familiar with this patch could give it a look, that'd be very useful,
since I'm not at all familiar with this code or feature.
next prev parent reply other threads:[~2014-05-15 19:07 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-05-09 21:13 [PATCHSET cgroup/for-3.16] cgroup: use css->refcnt for cgroup reference counting Tejun Heo
2014-05-09 21:13 ` [PATCH 1/9] cgroup: use restart_syscall() for mount retries Tejun Heo
2014-05-14 2:53 ` Li Zefan
2014-05-14 13:12 ` [PATCH v2 " Tejun Heo
2014-05-09 21:13 ` [PATCH 2/9] cgroup: rename cgroup->dummy_css to ->self and move it to the top Tejun Heo
2014-05-09 21:13 ` [PATCH 3/9] cgroup: separate out cgroup_has_live_children() from cgroup_destroy_locked() Tejun Heo
2014-05-09 21:13 ` [PATCH 4/9] cgroup: move check_for_release(parent) call to the end of cgroup_destroy_locked() Tejun Heo
2014-05-09 21:13 ` [PATCH 5/9] cgroup: move cgroup->sibling unlinking to cgroup_put() Tejun Heo
2014-05-09 21:13 ` [PATCH 6/9] cgroup: remove cgroup_destory_css_killed() Tejun Heo
2014-05-09 21:13 ` [PATCH 7/9] cgroup: bounce css release through css->destroy_work Tejun Heo
2014-05-09 21:13 ` [PATCH 8/9] cgroup: enable refcnting for root csses Tejun Heo
2014-05-09 21:13 ` [PATCH 9/9] cgroup: use cgroup->self.refcnt for cgroup refcnting Tejun Heo
2014-05-15 19:07 ` Stephen Warren [this message]
2014-05-15 21:56 ` Stephen Warren
2014-05-16 14:37 ` Tejun Heo
2014-05-16 15:43 ` [PATCH cgroup/for-3.16] cgroup: introduce CSS_NO_REF and skip refcnting on normal root csses Tejun Heo
2014-05-16 16:59 ` Stephen Warren
2014-05-16 17:09 ` [PATCH v2 " Tejun Heo
2014-05-16 17:19 ` Stephen Warren
2014-05-16 17:23 ` Tejun Heo
2014-05-13 16:59 ` [PATCHSET cgroup/for-3.16] cgroup: use css->refcnt for cgroup reference counting Tejun Heo
2014-05-14 3:15 ` Li Zefan
2014-05-14 17:04 ` Tejun Heo
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