linux-kernel - Re: [PATCH] zram: constify attribute

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Message-ID: <11272aaf-edac-4463-c0a9-de509d8901d6@gmail.com>
Date:   Mon, 3 Jul 2017 16:00:24 +0530
From:   Arvind Yadav <arvind.yadav.cs@...il.com>
To:     Sergey Senozhatsky <sergey.senozhatsky.work@...il.com>
Cc:     minchan@...nel.org, ngupta@...are.org, linux-kernel@...r.kernel.org
Subject: Re: [PATCH] zram: constify attribute_group structures.

Hi,


On Monday 03 July 2017 02:30 PM, Sergey Senozhatsky wrote:
> On (07/03/17 11:43), Arvind Yadav wrote:
>> attribute_groups are not supposed to change at runtime. All functions
>> working with attribute_groups provided by <linux/sysfs.h> work with const
>> attribute_group. So mark the non-const structs as const.
>>
>> File size before:
>>     text	   data	    bss	    dec	    hex	filename
>>     8293	    841	      4	   9138	   23b2	drivers/block/zram/zram_drv.o
>>
>> File size After adding 'const':
>>     text	   data	    bss	    dec	    hex	filename
>>     8357	    777	      4	   9138	   23b2	drivers/block/zram/zram_drv.o
> sorry, what exactly is the improvement here?
> we grew .text bigger, why should we be happy about it?
Yes, .text size is increased but .data size got decreased.
Overall size will be same. the text segment is often read-only,
to prevent a program from accidentally modifying its instructions.
Here, attribute_group should be const.
> 	-ss
Thanks,
~arvind