From: Li Zefan <lizefan-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
To: Kent Overstreet <koverstreet-hpIqsD4AKlfQT0dZR+AlfA@public.gmane.org>
Cc: Tejun Heo <tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>,
cgroups-u79uwXL29TY76Z2rM5mHXA@public.gmane.org,
containers-cunTk1MwBs9QetFLy7KEm3xJsTq8ys+cHZ5vskTnxNA@public.gmane.org,
cl-de/tnXTf+JLsfHDXvbKv3WD2FQJk+8+b@public.gmane.org,
linux-kernel-u79uwXL29TY76Z2rM5mHXA@public.gmane.org
Subject: Re: [PATCH 04/11] cgroup: use kzalloc() and list_del_init()
Date: Thu, 13 Jun 2013 11:13:23 +0800 [thread overview]
Message-ID: <51B938D3.4000605@huawei.com> (raw)
In-Reply-To: <20130613023831.GB10979@localhost>
On 2013/6/13 10:38, Kent Overstreet wrote:
> On Thu, Jun 13, 2013 at 10:36:40AM +0800, Li Zefan wrote:
>> On 2013/6/13 5:03, Tejun Heo wrote:
>>> There's no point in using kmalloc() and list_del() instead of the
>>> clearing variants for trivial stuff. We can live dangerously
>>> elsewhere. Use kzalloc() and list_del_init() instead and drop 0
>>> inits.
>>>
>>
>> Do you mean we prefer list_del_init() than list_del() in general? Then
>> in which cases do we prefer list_del()?
>
> IMO, list_del() is preferred when the object shouldn't be reused (i.e.
> it gets taken off a list and then it's freed).
yeah, this is what I have in my mind. I would wonder why list_del_init()
if I know that object won't be used anymore.
> list_del_init() could
> hide bugs.
>
Same here. I do worry a bit about this.
WARNING: multiple messages have this Message-ID (diff)
From: Li Zefan <lizefan@huawei.com>
To: Kent Overstreet <koverstreet@google.com>
Cc: Tejun Heo <tj@kernel.org>,
<containers@lists.linux-foundation.org>,
<cgroups@vger.kernel.org>, <linux-kernel@vger.kernel.org>,
<cl@linux-foundation.org>
Subject: Re: [PATCH 04/11] cgroup: use kzalloc() and list_del_init()
Date: Thu, 13 Jun 2013 11:13:23 +0800 [thread overview]
Message-ID: <51B938D3.4000605@huawei.com> (raw)
In-Reply-To: <20130613023831.GB10979@localhost>
On 2013/6/13 10:38, Kent Overstreet wrote:
> On Thu, Jun 13, 2013 at 10:36:40AM +0800, Li Zefan wrote:
>> On 2013/6/13 5:03, Tejun Heo wrote:
>>> There's no point in using kmalloc() and list_del() instead of the
>>> clearing variants for trivial stuff. We can live dangerously
>>> elsewhere. Use kzalloc() and list_del_init() instead and drop 0
>>> inits.
>>>
>>
>> Do you mean we prefer list_del_init() than list_del() in general? Then
>> in which cases do we prefer list_del()?
>
> IMO, list_del() is preferred when the object shouldn't be reused (i.e.
> it gets taken off a list and then it's freed).
yeah, this is what I have in my mind. I would wonder why list_del_init()
if I know that object won't be used anymore.
> list_del_init() could
> hide bugs.
>
Same here. I do worry a bit about this.
next prev parent reply other threads:[~2013-06-13 3:13 UTC|newest]
Thread overview: 51+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-12 21:03 [PATCHSET cgroup/for-3.11] cgroup: convert cgroup_subsys_state refcnt to percpu_ref Tejun Heo
2013-06-12 21:03 ` Tejun Heo
[not found] ` <1371070996-20613-1-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2013-06-12 21:03 ` [PATCH 01/11] cgroup: remove now unused css_depth() Tejun Heo
2013-06-12 21:03 ` Tejun Heo
2013-06-12 21:03 ` [PATCH 02/11] cgroup: consistently use @cset for struct css_set variables Tejun Heo
2013-06-12 21:03 ` Tejun Heo
2013-06-12 21:03 ` [PATCH 03/11] cgroup: bring some sanity to naming around cg_cgroup_link Tejun Heo
2013-06-12 21:03 ` Tejun Heo
[not found] ` <1371070996-20613-4-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2013-06-13 2:34 ` Li Zefan
2013-06-13 2:34 ` Li Zefan
2013-06-12 21:03 ` [PATCH 04/11] cgroup: use kzalloc() and list_del_init() Tejun Heo
2013-06-12 21:03 ` [PATCH 05/11] cgroup: clean up css_[try]get() and css_put() Tejun Heo
2013-06-12 21:03 ` Tejun Heo
[not found] ` <1371070996-20613-6-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2013-06-13 2:38 ` Li Zefan
2013-06-13 2:38 ` Li Zefan
2013-06-12 21:03 ` [PATCH 06/11] cgroup: rename CGRP_REMOVED to CGRP_DEAD Tejun Heo
2013-06-12 21:03 ` [PATCH 07/11] cgroup: drop unnecessary RCU dancing from __put_css_set() Tejun Heo
2013-06-12 21:03 ` Tejun Heo
2013-06-12 21:03 ` [PATCH 08/11] cgroup: remove cgroup->count and use Tejun Heo
2013-06-12 21:03 ` [PATCH 09/11] cgroup: reorder the operations in cgroup_destroy_locked() Tejun Heo
2013-06-12 21:03 ` Tejun Heo
2013-06-12 21:03 ` [PATCH 10/11] cgroup: split cgroup destruction into two steps Tejun Heo
2013-06-12 21:03 ` Tejun Heo
2013-06-12 21:03 ` Tejun Heo
2013-06-12 21:03 ` [PATCH 11/11] cgroup: use percpu refcnt for cgroup_subsys_states Tejun Heo
2013-06-12 21:03 ` [PATCH 04/11] cgroup: use kzalloc() and list_del_init() Tejun Heo
[not found] ` <1371070996-20613-5-git-send-email-tj-DgEjT+Ai2ygdnm+yROfE0A@public.gmane.org>
2013-06-13 2:36 ` Li Zefan
2013-06-13 2:36 ` Li Zefan
[not found] ` <51B93038.9010202-hv44wF8Li93QT0dZR+AlfA@public.gmane.org>
2013-06-13 2:38 ` Kent Overstreet
2013-06-13 2:38 ` Kent Overstreet
2013-06-13 2:41 ` Tejun Heo
2013-06-13 2:41 ` Tejun Heo
2013-06-13 2:41 ` Tejun Heo
[not found] ` <CAOS58YPv_uKeTqZSNF=sXTEnLn=LTbsdpBPM5K_ykXoVT-+CpA-JsoAwUIsXosN+BqQ9rBEUg@public.gmane.org>
2013-06-13 2:43 ` Kent Overstreet
2013-06-13 2:43 ` Kent Overstreet
2013-06-13 2:43 ` Kent Overstreet
2013-06-13 2:48 ` Tejun Heo
2013-06-13 2:48 ` Tejun Heo
[not found] ` <20130613024859.GA7432-9pTldWuhBndy/B6EtB590w@public.gmane.org>
2013-06-13 2:52 ` Kent Overstreet
2013-06-13 2:52 ` Kent Overstreet
2013-06-13 2:56 ` Tejun Heo
2013-06-13 2:56 ` Tejun Heo
[not found] ` <20130613025623.GB7432-9pTldWuhBndy/B6EtB590w@public.gmane.org>
2013-06-13 3:05 ` Tejun Heo
2013-06-13 3:05 ` Tejun Heo
2013-06-13 3:13 ` Li Zefan [this message]
2013-06-13 3:13 ` Li Zefan
2013-06-13 2:39 ` Tejun Heo
2013-06-13 2:39 ` Tejun Heo
2013-06-12 21:03 ` [PATCH 06/11] cgroup: rename CGRP_REMOVED to CGRP_DEAD Tejun Heo
2013-06-12 21:03 ` [PATCH 08/11] cgroup: remove cgroup->count and use Tejun Heo
2013-06-12 21:03 ` [PATCH 11/11] cgroup: use percpu refcnt for cgroup_subsys_states Tejun Heo
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