Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754202Ab2ECDnX (ORCPT ); Wed, 2 May 2012 23:43:23 -0400 Received: from mga01.intel.com ([192.55.52.88]:30606 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753154Ab2ECDnV (ORCPT ); Wed, 2 May 2012 23:43:21 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.71,315,1320652800"; d="scan'208";a="148757558" Date: Thu, 3 May 2012 11:43:11 +0800 From: Fengguang Wu To: Chris Mason Cc: Jan Kara , Andrew Morton , Jeff Moyer , Jens Axboe , linux-fsdevel@vger.kernel.org, LKML , Dave Chinner , Christoph Hellwig , Shaohua Li Subject: [PATCH] btrfs: lower metadata writeback threshold on low dirty threshold Message-ID: <20120503034311.GA14081@localhost> References: <20120408010600.GA31377@localhost> <20120411161344.309f12ef.akpm@linux-foundation.org> <20120412013224.GA5859@localhost> <20120412022040.GA6800@localhost> <20120412142634.GA16559@quack.suse.cz> <20120413014026.GA9027@localhost> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20120413014026.GA9027@localhost> User-Agent: Mutt/1.5.21 (2010-09-15) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1831 Lines: 37 This helps write performance when setting the dirty threshold to tiny numbers. 3.4.0-rc2 3.4.0-rc2-btrfs4+ ------------ ------------------------ 96.92 -0.4% 96.54 bay/thresh=1000M/btrfs-100dd-1-3.4.0-rc2 98.47 +0.0% 98.50 bay/thresh=1000M/btrfs-10dd-1-3.4.0-rc2 99.38 -0.3% 99.06 bay/thresh=1000M/btrfs-1dd-1-3.4.0-rc2 98.04 -0.0% 98.02 bay/thresh=100M/btrfs-100dd-1-3.4.0-rc2 98.68 +0.3% 98.98 bay/thresh=100M/btrfs-10dd-1-3.4.0-rc2 99.34 -0.0% 99.31 bay/thresh=100M/btrfs-1dd-1-3.4.0-rc2 ==> 88.98 +9.6% 97.53 bay/thresh=10M/btrfs-10dd-1-3.4.0-rc2 ==> 86.99 +13.1% 98.39 bay/thresh=10M/btrfs-1dd-1-3.4.0-rc2 ==> 2.75 +2442.4% 69.88 bay/thresh=1M/btrfs-10dd-1-3.4.0-rc2 ==> 3.31 +2634.1% 90.54 bay/thresh=1M/btrfs-1dd-1-3.4.0-rc2 Signed-off-by: Fengguang Wu --- fs/btrfs/disk-io.c | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) --- linux-next.orig/fs/btrfs/disk-io.c 2012-05-02 14:04:00.989262395 +0800 +++ linux-next/fs/btrfs/disk-io.c 2012-05-02 14:04:01.773262414 +0800 @@ -930,7 +930,8 @@ static int btree_writepages(struct addre /* this is a bit racy, but that's ok */ num_dirty = root->fs_info->dirty_metadata_bytes; - if (num_dirty < thresh) + if (num_dirty < min(thresh, + global_dirty_limit << (PAGE_CACHE_SHIFT-2))) return 0; } return btree_write_cache_pages(mapping, wbc); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/