From mboxrd@z Thu Jan 1 00:00:00 1970 From: Theodore Ts'o Subject: Re: [PATCH 10/35] undo-io: add new calls to and speed up the undo io manager Date: Tue, 5 May 2015 10:20:25 -0400 Message-ID: <20150505142025.GB12468@thunk.org> References: <20150402023359.25243.79782.stgit@birch.djwong.org> <20150402023506.25243.44459.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: linux-ext4@vger.kernel.org To: "Darrick J. Wong" Return-path: Received: from imap.thunk.org ([74.207.234.97]:45866 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2993156AbbEEOU1 (ORCPT ); Tue, 5 May 2015 10:20:27 -0400 Content-Disposition: inline In-Reply-To: <20150402023506.25243.44459.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Wed, Apr 01, 2015 at 07:35:06PM -0700, Darrick J. Wong wrote: > Implement pass-through calls for discard, zero-out, and readahead in > the IO manager so that we can take advantage of any underlying > support. > > Furthermore, improve tdb write-out speed by disabling locking and only > fsyncing at the end -- we don't care about locking because having > multiple writers to the undo file will produce an undo database full > of garbage blocks; and we only need to fsync at the end because if we > fail before the end, our undo file will lack the necessary superblock > data that e2undo requires to do replay safely. Without this, we call > fsync four times per tdb update(!) This reduces the overhead of using > undo_io while converting a 2TB FS to metadata_csum from 3+ hours to 55 > minutes. > > Signed-off-by: Darrick J. Wong Thanks, applied. - Ted