linux-kernel - Re: [PATCH] zram: reduce load operation in page_same

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Date:   Thu, 2 Mar 2017 16:02:47 +0900
From:   Minchan Kim <minchan@...nel.org>
To:     Sangwoo <sangwoo2.park@....com>
Cc:     ngupta@...are.org, sergey.senozhatsky.work@...il.com,
        linux-kernel@...r.kernel.org,
        Andrew Morton <akpm@...ux-foundation.org>
Subject: Re: [PATCH] zram: reduce load operation in page_same_filled

Hi Sangwoo,

On Thu, Mar 02, 2017 at 01:15:04PM +0900, Sangwoo wrote:
> In page_same_filled function, all elements in the page is compared
> with next index value. The current comparison routine compares
> the (i)th and (i+1)th values of the page.
> In this case, two load operaions occur for each comparison.
> But if we store first value of the page stores at 'val' variable
> and using it to compare with others, the load opearation is reduced.
> It reduce load operation per page by up to 64times.
> 
> Signed-off-by: Sangwoo <sangwoo2.park@....com>

The rule is that you should use your full name Sangwoo Park for SOB. :)
Anyway, Good spot!

FYI,
Ccing Andrew because he merges zram patches to mmotm tree.

Acked-by: Minchan Kim <minchan@...nel.org>

Thanks.