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Date: Sat, 21 Jun 2008 00:56:07 -0700
From: "Paul Menage" <menage@google.com>
To: "KOSAKI Motohiro" <kosaki.motohiro@jp.fujitsu.com>,
       "Balbir Singh" <balbir@linux.vnet.ibm.com>,
       "Pavel Emelianov" <xemul@openvz.org>
Subject: Re: [PATCH] introduce task cgroup v2
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       "Li Zefan" <lizf@cn.fujitsu.com>,
       "Andrew Morton" <akpm@linux-foundation.org>
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On Sun, Jun 15, 2008 at 6:32 PM, KOSAKI Motohiro
<kosaki.motohiro@jp.fujitsu.com> wrote:
>
> honestly, I used res_counter on early version.
> but I got bad performance.

Bad performance on the charge/uncharge?

The only difference I can see is that res_counter uses
spin_lock_irqsave()/spin_unlock_irqrestore(), and you're using plain
spin_lock()/spin_unlock().

Is the overhead of a pushf/cli/popf really going to matter compared
with the overhead of forking/exiting a task?

Or approaching this from the other side, does res_counter really need
irq-safe locking, or is it just being cautious?

Paul