From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pd0-f178.google.com (mail-pd0-f178.google.com [209.85.192.178]) by kanga.kvack.org (Postfix) with ESMTP id 7EE7A6B0037 for ; Thu, 24 Apr 2014 14:57:44 -0400 (EDT) Received: by mail-pd0-f178.google.com with SMTP id fp1so69340pdb.23 for ; Thu, 24 Apr 2014 11:57:44 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTP id hp1si3225680pad.57.2014.04.24.11.57.43 for ; Thu, 24 Apr 2014 11:57:43 -0700 (PDT) Date: Thu, 24 Apr 2014 14:57:40 -0400 From: Matthew Wilcox Subject: Re: [PATCH v3 5/7] swap: Use bdev_read_page() / bdev_write_page() Message-ID: <20140424185740.GE5886@linux.intel.com> References: <9fb0b4031b0fba312963a7cc21bf258d944cddcf.1397429628.git.matthew.r.wilcox@intel.com> <20140424111817.9cc62b2ff1e368c5cf27d262@linux-foundation.org> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20140424111817.9cc62b2ff1e368c5cf27d262@linux-foundation.org> Sender: owner-linux-mm@kvack.org List-ID: To: Andrew Morton Cc: Matthew Wilcox , linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Hugh Dickins On Thu, Apr 24, 2014 at 11:18:17AM -0700, Andrew Morton wrote: > On Sun, 13 Apr 2014 18:59:54 -0400 Matthew Wilcox wrote: > > > mm/page_io.c | 23 +++++++++++++++++++++-- > > 1 file changed, 21 insertions(+), 2 deletions(-) > > Some changelog here would be nice. What were the reasons for the > change? Any observable performance changes? Whoops ... I could swear I wrote one. Wonder what happened to it. Here was all I had: We can avoid allocating a BIO if we use the writepage path instead of the Direct I/O path. But that's kind of lame. I don't have any performance numbers right now, so how about we go with: By calling the device driver to write the page directly, we avoid allocating a BIO, which allows us to free memory without allocating memory. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org