linux-kernel - Re: [RESEND PATCH] fs/super.c set_anon

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Date:	Fri, 30 Nov 2012 11:10:02 +0530
From:	Abhijit Pawar <abhi.c.pawar@...il.com>
To:	Al Viro <viro@...IV.linux.org.uk>
CC:	Abhijit Pawar <abhi.c.pawar@...il.com>,
	linux-fsdevel@...r.kernel.org,
	"linux-btrfs@...r.kernel.org" <linux-btrfs@...r.kernel.org>,
	linux-kernel@...r.kernel.org, gregkh@...uxfoundation.org
Subject: Re: [RESEND PATCH] fs/super.c set_anon_super calling optimization

On 11/30/2012 09:35 AM, Al Viro wrote:
> On Fri, Oct 26, 2012 at 11:14:41AM -0200, Carlos Maiolino wrote:
>> Hi,
>>
>> On Thu, Oct 25, 2012 at 05:08:19PM +0530, Abhijit Pawar wrote:
>>> Hi,
>>> set_anon_super is called by many filesystems. Some call directly and
>>> some call through the wrapper. Many of them in the wrapper's call to
>>> this function are passing the second argument to this function which
>>> is not used anywhere.
>>>
>>> This patch replaces the second variable with NULL.
>>>
>>
>> If the variable isn't used anymore, why don't just get rid of it, instead of
>> call the function passing a NULL pointer on it?
> 
> 	Because we want it to be a valid sget() callback.  I doubt that this
> optimization is worth doing, though - might even micro-pessimize the things
> on architectures where all arguments are passed in registers.
> 
Al,
Yes. it will be helpful in registers case.

-- 
-
Abhijit
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