Date: Fri, 25 Apr 2014 10:01:01 -0400
From: Matthew Wilcox <willy@linux.intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <matthew.r.wilcox@intel.com>, linux-fsdevel@vger.kernel.org,
        linux-mm@kvack.org, linux-kernel@vger.kernel.org,
        Hugh Dickins <hughd@google.com>
Subject: Re: [PATCH v3 5/7] swap: Use bdev_read_page() / bdev_write_page()
Message-ID: <20140425140100.GF5886@linux.intel.com>
References: <cover.1397429628.git.matthew.r.wilcox@intel.com>
 <9fb0b4031b0fba312963a7cc21bf258d944cddcf.1397429628.git.matthew.r.wilcox@intel.com>
 <20140424111817.9cc62b2ff1e368c5cf27d262@linux-foundation.org>
 <20140424185740.GE5886@linux.intel.com>
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Sender: linux-kernel-owner@vger.kernel.org

On Thu, Apr 24, 2014 at 02:57:40PM -0400, Matthew Wilcox wrote:
> By calling the device driver to write the page directly, we avoid
> allocating a BIO, which allows us to free memory without allocating
> memory.

I got handed some performance numbers last night!  Next time you're updating
the patch description, please use:

By calling the device driver to write the page directly, we avoid
allocating a BIO, which allows us to free memory without allocating
memory.  When running a swap-heavy benchmark, system time is reduced by
about 20%.

Tested-by: Dheeraj Reddy <dheeraj.reddy@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>
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