linux-kernel - Re: [PATCH] xen: selfballoon: remove unnecessary static in frontswap

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Message-ID: <d60b1758-bd77-202a-067d-07c8f3db578b@embeddedor.com>
Date:   Fri, 21 Jul 2017 15:46:46 -0500
From:   "Gustavo A. R. Silva" <garsilva@...eddedor.com>
To:     Juergen Gross <jgross@...e.com>,
        Boris Ostrovsky <boris.ostrovsky@...cle.com>
Cc:     xen-devel@...ts.xenproject.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] xen: selfballoon: remove unnecessary static in
 frontswap_selfshrink()

Hi Juergen,

On 07/21/2017 02:36 AM, Juergen Gross wrote:
> On 04/07/17 20:34, Gustavo A. R. Silva wrote:
>> Remove unnecessary static on local variables last_frontswap_pages and
>> tgt_frontswap_pages. Such variables are initialized before being used,
>> on every execution path throughout the function. The statics have no
>> benefit and, removing them reduce the code size.
>>
>> This issue was detected using Coccinelle and the following semantic patch:
>>
>> @bad exists@
>> position p;
>> identifier x;
>> type T;
>> @@
>>
>> static T x@p;
>> ...
>> x = <+...x...+>
>>
>> @@
>> identifier x;
>> expression e;
>> type T;
>> position p != bad.p;
>> @@
>>
>> -static
>>  T x@p;
>>  ... when != x
>>      when strict
>> ?x = e;
>>
>> You can see a significant difference in the code size after executing
>> the size command, before and after the code change:
>>
>> before:
>>    text	   data	    bss	    dec	    hex	filename
>>    5633	   3452	    384	   9469	   24fd	drivers/xen/xen-selfballoon.o
>>
>> after:
>>    text	   data	    bss	    dec	    hex	filename
>>    5576	   3308	    256	   9140	   23b4	drivers/xen/xen-selfballoon.o
>>
>> Signed-off-by: Gustavo A. R. Silva <garsilva@...eddedor.com>
>
> Reviewed-by: Juergen Gross <jgross@...e.com>
>

Thank you!

-- 
Gustavo A. R. Silva