From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/6] fs: Take mapping lock in generic read paths
Date: Thu, 31 Jan 2013 15:59:40 -0800 [thread overview]
Message-ID: <20130131155940.7b1f8e0e.akpm@linux-foundation.org> (raw)
In-Reply-To: <1359668994-13433-3-git-send-email-jack@suse.cz>
On Thu, 31 Jan 2013 22:49:50 +0100
Jan Kara <jack@suse.cz> wrote:
> Add mapping lock to struct address_space and grab it in all paths
> creating pages in page cache to read data into them. That means buffered
> read, readahead, and page fault code.
Boy, this does look expensive in both speed and space.
As you pointed out in [0/n], it's 2-3%. As always with pagecache
stuff, the cost of filling the page generally swamps any inefficiencies
in preparing that page.
WARNING: multiple messages have this Message-ID (diff)
From: Andrew Morton <akpm@linux-foundation.org>
To: Jan Kara <jack@suse.cz>
Cc: LKML <linux-kernel@vger.kernel.org>,
linux-fsdevel@vger.kernel.org, linux-mm@kvack.org
Subject: Re: [PATCH 2/6] fs: Take mapping lock in generic read paths
Date: Thu, 31 Jan 2013 15:59:40 -0800 [thread overview]
Message-ID: <20130131155940.7b1f8e0e.akpm@linux-foundation.org> (raw)
In-Reply-To: <1359668994-13433-3-git-send-email-jack@suse.cz>
On Thu, 31 Jan 2013 22:49:50 +0100
Jan Kara <jack@suse.cz> wrote:
> Add mapping lock to struct address_space and grab it in all paths
> creating pages in page cache to read data into them. That means buffered
> read, readahead, and page fault code.
Boy, this does look expensive in both speed and space.
As you pointed out in [0/n], it's 2-3%. As always with pagecache
stuff, the cost of filling the page generally swamps any inefficiencies
in preparing that page.
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next prev parent reply other threads:[~2013-01-31 23:59 UTC|newest]
Thread overview: 46+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-01-31 21:49 [PATCH 0/6 RFC] Mapping range lock Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-01-31 21:49 ` [PATCH 1/6] lib: Implement range locks Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-01-31 23:57 ` Andrew Morton
2013-01-31 23:57 ` Andrew Morton
2013-02-04 16:41 ` Jan Kara
2013-02-04 16:41 ` Jan Kara
2013-02-11 5:42 ` Michel Lespinasse
2013-02-11 5:42 ` Michel Lespinasse
2013-02-11 10:27 ` Jan Kara
2013-02-11 10:27 ` Jan Kara
2013-02-11 11:03 ` Michel Lespinasse
2013-02-11 11:03 ` Michel Lespinasse
2013-02-11 12:58 ` Jan Kara
2013-02-11 12:58 ` Jan Kara
2013-01-31 21:49 ` [PATCH 2/6] fs: Take mapping lock in generic read paths Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-01-31 23:59 ` Andrew Morton [this message]
2013-01-31 23:59 ` Andrew Morton
2013-02-04 12:47 ` Jan Kara
2013-02-04 12:47 ` Jan Kara
2013-02-08 14:59 ` Jan Kara
2013-02-08 14:59 ` Jan Kara
2013-01-31 21:49 ` [PATCH 3/6] fs: Provide function to take mapping lock in buffered write path Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-01-31 21:49 ` [PATCH 4/6] fs: Don't call dio_cleanup() before submitting all bios Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-01-31 21:49 ` [PATCH 5/6] fs: Take mapping lock during direct IO Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-01-31 21:49 ` [PATCH 6/6] ext3: Convert ext3 to use mapping lock Jan Kara
2013-01-31 21:49 ` Jan Kara
2013-02-01 0:07 ` [PATCH 0/6 RFC] Mapping range lock Andrew Morton
2013-02-01 0:07 ` Andrew Morton
2013-02-04 9:29 ` Zheng Liu
2013-02-04 9:29 ` Zheng Liu
2013-02-04 12:38 ` Jan Kara
2013-02-04 12:38 ` Jan Kara
2013-02-05 23:25 ` Dave Chinner
2013-02-05 23:25 ` Dave Chinner
2013-02-06 19:25 ` Jan Kara
2013-02-06 19:25 ` Jan Kara
2013-02-07 2:43 ` Dave Chinner
2013-02-07 2:43 ` Dave Chinner
2013-02-07 11:06 ` Jan Kara
2013-02-07 11:06 ` Jan Kara
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