From: Theodore Ts'o Subject: Re: [PATCH 23/25] ext2fs: add readahead method to improve scanning Date: Thu, 11 Sep 2014 17:10:31 -0400 Message-ID: <20140911211031.GA17990@thunk.org> References: <20140908231135.25904.66591.stgit@birch.djwong.org> <20140908231408.25904.47150.stgit@birch.djwong.org> Mime-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Transfer-Encoding: QUOTED-PRINTABLE Cc: linux-ext4@vger.kernel.org, Andreas Dilger To: "Darrick J. Wong" Return-path: Received: from imap.thunk.org ([74.207.234.97]:52055 "EHLO imap.thunk.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1757488AbaIKVKg (ORCPT ); Thu, 11 Sep 2014 17:10:36 -0400 Content-Disposition: inline In-Reply-To: <20140908231408.25904.47150.stgit@birch.djwong.org> Sender: linux-ext4-owner@vger.kernel.org List-ID: On Mon, Sep 08, 2014 at 04:14:08PM -0700, Darrick J. Wong wrote: > Fr=F8m: Andreas Dilger >=20 > Add a readahead method for prefetching ranges of disk blocks. This i= s > useful for inode table scanning, and other large contiguous ranges of > blocks, and may also prove useful for random block prefetch, since it > will allow reordering of the IO without waiting synchronously for the > reads to complete. >=20 > It is currently using the posix_fadvise(POSIX_FADV_WILLNEED) > interface, as this proved most efficient during our testing. >=20 > [darrick.wong@oracle.com] > Make the arguments to the readahead function take the same ULL values > as the other IO functions, and return an appropriate error code when > fadvise isn't available. >=20 > Signed-off-by: Andreas Dilger > Signed-off-by: Darrick J. Wong > --- > lib/ext2fs/ext2_io.h | 8 +++++++- > lib/ext2fs/io_manager.c | 9 +++++++++ > lib/ext2fs/unix_io.c | 27 ++++++++++++++++++++++++--- > 3 files changed, 40 insertions(+), 4 deletions(-) Could you also plumb through the new method in test_io.c? Because we often use this to interposed between mke2fs or e2fsprogs and unix_io.c for debugging purposes. Thanks! - Ted -- To unsubscribe from this list: send the line "unsubscribe linux-ext4" i= n the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html