linux-kernel - Re: [PATCH 0/3 v2] mm: Batch page reclamation under shink_page

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Message-ID: <20120911053657.GC14494@bbox>
Date:	Tue, 11 Sep 2012 14:36:57 +0900
From:	Minchan Kim <minchan@...nel.org>
To:	Tim Chen <tim.c.chen@...ux.intel.com>
Cc:	Andrew Morton <akpm@...ux-foundation.org>,
	Mel Gorman <mel@....ul.ie>,
	Johannes Weiner <hannes@...xchg.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@...fujitsu.com>,
	Andrea Arcangeli <aarcange@...hat.com>,
	David Rientjes <rientjes@...gle.com>,
	Michal Hocko <mhocko@...e.cz>,
	Xiao Guangrong <xiaoguangrong@...ux.vnet.ibm.com>,
	Paul Gortmaker <paul.gortmaker@...driver.com>,
	Matthew Wilcox <willy@...ux.intel.com>,
	"Kirill A. Shutemov" <kirill.shutemov@...ux.intel.com>,
	Andi Kleen <ak@...ux.intel.com>, linux-mm@...ck.org,
	linux-kernel <linux-kernel@...r.kernel.org>,
	Alex Shi <alex.shi@...el.com>,
	Fengguang Wu <fengguang.wu@...el.com>
Subject: Re: [PATCH 0/3 v2] mm: Batch page reclamation under shink_page_list

Hi Tim,

On Mon, Sep 10, 2012 at 09:19:20AM -0700, Tim Chen wrote:
> This is the second version of the patch series. Thanks to Matthew Wilcox 
> for many valuable suggestions on improving the patches.
> 
> To do page reclamation in shrink_page_list function, there are two
> locks taken on a page by page basis.  One is the tree lock protecting
> the radix tree of the page mapping and the other is the
> mapping->i_mmap_mutex protecting the mapped
> pages.  I try to batch the operations on pages sharing the same lock
> to reduce lock contentions.  The first patch batch the operations protected by
> tree lock while the second and third patch batch the operations protected by 
> the i_mmap_mutex.
> 
> I managed to get 14% throughput improvement when with a workload putting
> heavy pressure of page cache by reading many large mmaped files
> simultaneously on a 8 socket Westmere server.
> 
> Tim
> 
> Signed-off-by: Tim Chen <tim.c.chen@...ux.intel.com>

If you send next versions, please use git-format-patch --thread style.
Quote from man
"       If given --thread, git-format-patch will generate In-Reply-To and References
       headers to make the second and subsequent patch mails appear as replies to the
       first mail; this also generates a Message-Id header to reference.
"

It helps making your all patches in this series thread type in mailbox
so reviewers can find all patches related to a subject easily.

Thanks.

-- 
Kind regards,
Minchan Kim
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