linux-kernel - Re: [RFC] mm/zsmalloc: remove redundant SetPagePrivate2 in create_page

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Message-ID: <20170214161653.GA10321@tigerII.localdomain>
Date:   Wed, 15 Feb 2017 01:16:53 +0900
From:   Sergey Senozhatsky <sergey.senozhatsky@...il.com>
To:     Yisheng Xie <xieyisheng1@...wei.com>
Cc:     akpm@...ux-foundation.org, minchan@...nel.org, ngupta@...are.org,
        sergey.senozhatsky.work@...il.com, linux-mm@...ck.org,
        linux-kernel@...r.kernel.org, guohanjun@...wei.com
Subject: Re: [RFC] mm/zsmalloc: remove redundant SetPagePrivate2 in
 create_page_chain

On (02/14/17 20:48), Yisheng Xie wrote:
> We had used page->lru to link the component pages (except the first
> page) of a zspage, and used INIT_LIST_HEAD(&page->lru) to init it.
> Therefore, to get the last page's next page, which is NULL, we had to
> use page flag PG_Private_2 to identify it.
> 
> But now, we use page->freelist to link all of the pages in zspage and
> init the page->freelist as NULL for last page, so no need to use
> PG_Private_2 anymore.
> 
> This patch is to remove redundant SetPagePrivate2 in create_page_chain
> and ClearPagePrivate2 in reset_page(). Maybe can save few cycles for
> migration of zsmalloc page :)
> 
> Signed-off-by: Yisheng Xie <xieyisheng1@...wei.com>

looks good to me.

Reviewed-by: Sergey Senozhatsky <sergey.senozhatsky@...il.com>

	-ss