From: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
To: Michal Hocko <mhocko-AlSwsSmVLrQ@public.gmane.org>
Cc: linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org
Subject: Re: [PATCH 3/8] cgroup: use cgroup_lock_live_group(parent) in cgroup_create()
Date: Thu, 1 Nov 2012 08:43:20 -0700 [thread overview]
Message-ID: <20121101154320.GA8712@htj.dyndns.org> (raw)
In-Reply-To: <20121101151556.GB5065-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
Hey, Michal.
On Thu, Nov 01, 2012 at 04:15:56PM +0100, Michal Hocko wrote:
> > if (!cgroup_lock_live_group(parent))
> > return -ENODEV;
> >
> > cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
> > if (!cgrp)
> > return -ENOMEM;
>
> this needs to drop the lock of course but it doesn't make it much more
> complicated...
Yeah, now look at the error exit path of the function. You have to
reorder them too so that it matches the changed order above, which is
all fine and dandy, but one way is not necessarily better than the
other, so there's no good reason to incur that churn.
Thanks.
--
tejun
WARNING: multiple messages have this Message-ID (diff)
From: Tejun Heo <tj@kernel.org>
To: Michal Hocko <mhocko@suse.cz>
Cc: lizefan@huawei.com, hannes@cmpxchg.org, bsingharora@gmail.com,
kamezawa.hiroyu@jp.fujitsu.com,
containers@lists.linux-foundation.org, cgroups@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: Re: [PATCH 3/8] cgroup: use cgroup_lock_live_group(parent) in cgroup_create()
Date: Thu, 1 Nov 2012 08:43:20 -0700 [thread overview]
Message-ID: <20121101154320.GA8712@htj.dyndns.org> (raw)
In-Reply-To: <20121101151556.GB5065@dhcp22.suse.cz>
Hey, Michal.
On Thu, Nov 01, 2012 at 04:15:56PM +0100, Michal Hocko wrote:
> > if (!cgroup_lock_live_group(parent))
> > return -ENODEV;
> >
> > cgrp = kzalloc(sizeof(*cgrp), GFP_KERNEL);
> > if (!cgrp)
> > return -ENOMEM;
>
> this needs to drop the lock of course but it doesn't make it much more
> complicated...
Yeah, now look at the error exit path of the function. You have to
reorder them too so that it matches the changed order above, which is
all fine and dandy, but one way is not necessarily better than the
other, so there's no good reason to incur that churn.
Thanks.
--
tejun
next prev parent reply other threads:[~2012-11-01 15:43 UTC|newest]
Thread overview: 128+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-10-31 4:22 [PATCHSET] cgroup: simplify cgroup removal path Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 4:22 ` [PATCH 1/8] cgroup: kill cgroup_subsys->__DEPRECATED_clear_css_refs Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-2-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 13:21 ` Glauber Costa
2012-10-31 13:21 ` Glauber Costa
[not found] ` <509125D9.8070100-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-31 16:38 ` Tejun Heo
2012-10-31 16:38 ` Tejun Heo
2012-10-31 13:21 ` Glauber Costa
2012-10-31 14:37 ` Michal Hocko
2012-10-31 14:37 ` Michal Hocko
[not found] ` <20121031143751.GA22809-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 16:41 ` Tejun Heo
2012-10-31 16:41 ` Tejun Heo
2012-10-31 16:41 ` Tejun Heo
[not found] ` <20121031164123.GD2945-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-31 16:48 ` Michal Hocko
2012-10-31 16:48 ` Michal Hocko
[not found] ` <20121031164855.GI22809-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 17:22 ` Tejun Heo
2012-10-31 17:22 ` Tejun Heo
2012-10-31 14:37 ` Michal Hocko
2012-11-02 9:23 ` Kamezawa Hiroyuki
2012-11-02 9:23 ` Kamezawa Hiroyuki
2012-11-02 9:23 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` [PATCH 2/8] cgroup: kill CSS_REMOVED Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-3-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 15:39 ` Michal Hocko
2012-10-31 15:39 ` Michal Hocko
[not found] ` <20121031153926.GC22809-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 16:57 ` Tejun Heo
2012-10-31 16:57 ` Tejun Heo
[not found] ` <20121031165739.GE2945-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-31 17:06 ` Glauber Costa
2012-10-31 17:06 ` Glauber Costa
[not found] ` <50915A87.4070504-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-31 17:10 ` Tejun Heo
2012-10-31 17:10 ` Tejun Heo
[not found] ` <CAOS58YP=CjTPFdETLRXnc3gXEzX2=EEe2dMdSh3Eov7zRfV4Qg-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-10-31 17:19 ` Glauber Costa
2012-10-31 17:19 ` Glauber Costa
[not found] ` <50915DB7.5020706-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-31 17:25 ` Tejun Heo
2012-10-31 17:25 ` Tejun Heo
[not found] ` <20121031172522.GJ2945-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-31 17:38 ` Glauber Costa
2012-10-31 17:38 ` Glauber Costa
[not found] ` <50916218.3090301-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-31 17:44 ` Tejun Heo
2012-10-31 17:44 ` Tejun Heo
2012-10-31 17:39 ` Glauber Costa
2012-10-31 17:39 ` Glauber Costa
2012-10-31 19:16 ` Michal Hocko
2012-10-31 19:16 ` Michal Hocko
[not found] ` <20121031191602.GB1271-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 19:33 ` Tejun Heo
2012-10-31 19:33 ` Tejun Heo
2012-10-31 15:39 ` Michal Hocko
2012-11-02 9:30 ` Kamezawa Hiroyuki
2012-11-02 9:30 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` [PATCH 3/8] cgroup: use cgroup_lock_live_group(parent) in cgroup_create() Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-4-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 15:55 ` Michal Hocko
2012-10-31 15:55 ` Michal Hocko
[not found] ` <20121031155514.GD22809-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 17:04 ` Tejun Heo
2012-10-31 17:04 ` Tejun Heo
2012-10-31 17:04 ` Tejun Heo
[not found] ` <20121031170431.GF2945-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-11-01 9:16 ` Michal Hocko
2012-11-01 9:16 ` Michal Hocko
[not found] ` <20121101091644.GA8533-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-11-01 14:52 ` Tejun Heo
2012-11-01 14:52 ` Tejun Heo
[not found] ` <CAOS58YM+kRtspVUzmnSmOmrDoNS_kF6KA02zWGxqH5FUcRWo1Q-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2012-11-01 15:05 ` Michal Hocko
2012-11-01 15:05 ` Michal Hocko
2012-11-01 15:05 ` Michal Hocko
[not found] ` <20121101150532.GA5065-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-11-01 15:15 ` Michal Hocko
2012-11-01 15:15 ` Michal Hocko
2012-11-01 15:15 ` Michal Hocko
[not found] ` <20121101151556.GB5065-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-11-01 15:43 ` Tejun Heo [this message]
2012-11-01 15:43 ` Tejun Heo
2012-11-02 9:37 ` Kamezawa Hiroyuki
2012-11-02 9:37 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` Tejun Heo
2012-10-31 4:22 ` [PATCH 4/8] cgroup: deactivate CSS's and mark cgroup dead before invoking ->pre_destroy() Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-5-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 13:42 ` Glauber Costa
2012-10-31 13:42 ` Glauber Costa
2012-10-31 16:05 ` Michal Hocko
2012-10-31 16:05 ` Michal Hocko
2012-11-02 9:43 ` Kamezawa Hiroyuki
2012-11-02 9:43 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` [PATCH 5/8] cgroup: remove CGRP_WAIT_ON_RMDIR, cgroup_exclude_rmdir() and cgroup_release_and_wakeup_rmdir() Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-6-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 16:27 ` Michal Hocko
2012-10-31 16:27 ` Michal Hocko
[not found] ` <20121031162735.GF22809-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 17:16 ` Tejun Heo
2012-10-31 17:16 ` Tejun Heo
2012-11-02 9:53 ` Kamezawa Hiroyuki
2012-11-02 9:53 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` [PATCH 6/8] memcg: make mem_cgroup_reparent_charges non failing Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-7-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-11-02 9:54 ` Kamezawa Hiroyuki
2012-11-02 9:54 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` [PATCH 7/8] hugetlb: do not fail in hugetlb_cgroup_pre_destroy Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-8-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-11-02 9:56 ` Kamezawa Hiroyuki
2012-11-02 9:56 ` Kamezawa Hiroyuki
2012-11-02 9:56 ` Kamezawa Hiroyuki
2012-10-31 4:22 ` [PATCH 8/8] cgroup: make ->pre_destroy() return void Tejun Heo
2012-10-31 4:22 ` Tejun Heo
[not found] ` <1351657365-25055-9-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 13:57 ` Vivek Goyal
2012-10-31 13:57 ` Vivek Goyal
2012-10-31 16:28 ` Michal Hocko
2012-10-31 16:28 ` Michal Hocko
2012-11-02 9:57 ` Kamezawa Hiroyuki
2012-11-02 9:57 ` Kamezawa Hiroyuki
2012-10-31 13:49 ` [PATCHSET] cgroup: simplify cgroup removal path Glauber Costa
2012-10-31 13:49 ` Glauber Costa
[not found] ` <50912C6D.6020000-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-31 17:18 ` Tejun Heo
2012-10-31 17:18 ` Tejun Heo
[not found] ` <20121031171849.GH2945-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-31 17:24 ` Glauber Costa
2012-10-31 17:24 ` Glauber Costa
2012-10-31 17:24 ` Glauber Costa
[not found] ` <50915EB6.3060704-bzQdu9zFT3WakBO8gow8eQ@public.gmane.org>
2012-10-31 17:26 ` Tejun Heo
2012-10-31 17:26 ` Tejun Heo
[not found] ` <20121031172617.GK2945-Gd/HAXX7CRxy/B6EtB590w@public.gmane.org>
2012-10-31 17:33 ` Glauber Costa
2012-10-31 17:33 ` Glauber Costa
2012-10-31 16:31 ` Michal Hocko
2012-10-31 16:31 ` Michal Hocko
[not found] ` <20121031163134.GH22809-2MMpYkNvuYDjFM9bn6wA6Q@public.gmane.org>
2012-10-31 16:35 ` Tejun Heo
2012-10-31 16:35 ` Tejun Heo
-- strict thread matches above, loose matches on Subject: below --
2012-10-31 18:16 [PATCHSET v2] " Tejun Heo
2012-10-31 18:16 ` [PATCH 3/8] cgroup: use cgroup_lock_live_group(parent) in cgroup_create() Tejun Heo
[not found] ` <1351707391-22287-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 18:16 ` Tejun Heo
2012-10-31 19:44 [PATCHSET RESEND v2] cgroup: simplify cgroup removal path Tejun Heo
[not found] ` <1351712650-23709-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-10-31 19:44 ` [PATCH 3/8] cgroup: use cgroup_lock_live_group(parent) in cgroup_create() Tejun Heo
2012-10-31 19:44 ` Tejun Heo
[not found] ` <1351712650-23709-4-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2012-11-02 10:03 ` Kamezawa Hiroyuki
2012-11-02 10:03 ` Kamezawa Hiroyuki
2012-11-05 5:36 ` Li Zefan
2012-11-05 5:36 ` Li Zefan
2012-11-05 5:36 ` Li Zefan
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=20121101154320.GA8712@htj.dyndns.org \
--to=tj-dgejt+ai2ygdnm+yrofe0a@public.gmane.org \
--cc=cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org \
--cc=hannes-druUgvl0LCNAfugRpC6u6w@public.gmane.org \
--cc=linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org \
--cc=mhocko-AlSwsSmVLrQ@public.gmane.org \
/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.