From: Li Zefan <lizf@cn.fujitsu.com>
To: Paul Menage <menage@google.com>
Cc: "akpm >> Andrew Morton" <akpm@linux-foundation.org>,
Stephane Eranian <eranian@google.com>,
LKML <linux-kernel@vger.kernel.org>,
containers@lists.linux-foundation.org
Subject: Re: [PATCH 1/7] cgroups: Shrink struct cgroup_subsys
Date: Wed, 10 Nov 2010 08:52:34 +0800 [thread overview]
Message-ID: <4CD9ECD2.3030805@cn.fujitsu.com> (raw)
In-Reply-To: <AANLkTim6d1fQLZbkmZST3PTN0RMSs3m=oossF81pYBn9@mail.gmail.com>
Paul Menage wrote:
> On Sun, Nov 7, 2010 at 9:23 PM, Li Zefan <lizf@cn.fujitsu.com> wrote:
>> bool active;
>> bool disabled;
>> ...
>>
>> ?
>>
>> With alignment 5-8 bool values == 8 bytes in 64-bit machine, compared to
>> 4 bytes with the approach this patch takes.
>
> I meant specifying it as:
>
> bool active:1;
> bool disabled:1;
>
It won't compile, but unsigned char active:1 will do. ;)
> i.e. keeping the bit-sized flags but also keeping the bool semantics.
> Having said that, I'm not really sure why saving 12 bytes per
> subsystem is worth a patch.
Every thing that reduces code size (without sacrifice readability
and maintain maintainability) should be worth.
This is one of the reasons we accept patches that replacing
kmalloc+memset with kzalloc, which just saves 8 bytes in my box.
next prev parent reply other threads:[~2010-11-10 0:51 UTC|newest]
Thread overview: 38+ messages / expand[flat|nested] mbox.gz Atom feed top
2010-10-22 8:09 [PATCH 0/7] cgroups: Allow to bind/unbind subsystems to/from non-trival hierarchy Li Zefan
2010-10-22 8:09 ` [PATCH 1/7] cgroups: Shrink struct cgroup_subsys Li Zefan
2010-10-28 23:34 ` Paul Menage
2010-11-08 5:23 ` Li Zefan
2010-11-09 21:05 ` Paul Menage
2010-11-10 0:52 ` Li Zefan [this message]
2010-11-10 1:53 ` Paul Menage
2010-11-10 2:06 ` Li Zefan
2010-11-10 2:15 ` Paul Menage
2010-10-22 8:09 ` [PATCH 2/7] cgroups: Allow to bind a subsystem to a cgroup hierarchy Li Zefan
2010-10-22 12:47 ` Peter Zijlstra
2010-10-25 0:59 ` Li Zefan
2010-10-22 21:38 ` Matt Helsley
2010-10-25 1:23 ` Li Zefan
2010-10-28 23:57 ` Paul Menage
2010-10-28 23:55 ` Paul Menage
2010-11-08 5:26 ` Li Zefan
2010-10-22 8:10 ` [PATCH 3/7] cgroups: Allow to unbind subsystem from a cgroup hierarachy Li Zefan
2010-10-29 0:02 ` Paul Menage
2010-10-22 8:11 ` [PATCH 4/7] cgroups: Mark some subsystems bindable Li Zefan
2010-10-22 8:11 ` [PATCH 5/7] cgroups: Make freezer subsystem bindable Li Zefan
2010-10-22 20:57 ` Matt Helsley
2010-10-22 21:46 ` Matt Helsley
2010-10-29 0:06 ` Paul Menage
2010-10-22 21:57 ` Matt Helsley
2010-10-25 1:15 ` Li Zefan
2010-10-22 8:12 ` [PATCH 6/7] cgroups: Warn if a bindable subsystem calls css_get() Li Zefan
2010-10-29 0:05 ` Paul Menage
2010-10-22 8:12 ` [PATCH 7/7] cgroups: Update documentation for bindable subsystems Li Zefan
2010-10-25 0:36 ` KAMEZAWA Hiroyuki
2010-10-25 0:52 ` Li Zefan
2010-10-25 0:56 ` Li Zefan
2010-10-29 0:13 ` Paul Menage
2010-10-29 0:15 ` Paul Menage
2010-11-08 5:27 ` Li Zefan
2010-10-22 12:50 ` [PATCH 0/7] cgroups: Allow to bind/unbind subsystems to/from non-trival hierarchy Peter Zijlstra
2010-10-25 1:07 ` Li Zefan
2010-10-28 23:33 ` Paul Menage
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