From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932327Ab0LMGzl (ORCPT ); Mon, 13 Dec 2010 01:55:41 -0500 Received: from mga02.intel.com ([134.134.136.20]:28331 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755213Ab0LMGtn (ORCPT ); Mon, 13 Dec 2010 01:49:43 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.59,335,1288594800"; d="scan'208";a="583111651" Message-Id: <20101213064841.543258832@intel.com> User-Agent: quilt/0.48-1 Date: Mon, 13 Dec 2010 14:43:26 +0800 From: Wu Fengguang To: Andrew Morton CC: Jan Kara , Chris Mason , Wu Fengguang CC: Christoph Hellwig CC: Trond Myklebust CC: Dave Chinner CC: "Theodore Ts'o" CC: Peter Zijlstra CC: Mel Gorman CC: Rik van Riel CC: KOSAKI Motohiro CC: Greg Thelen CC: Minchan Kim Cc: linux-mm Cc: Cc: LKML Subject: [PATCH 37/47] btrfs: lower the dirty balacing rate limit References: <20101213064249.648862451@intel.com> Content-Disposition: inline; filename=btrfs-limit-nr-dirtied.patch Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Call balance_dirty_pages_ratelimit_nr() on every 16 pages dirtied. Experiments show that larger intervals (in the original code) can easily make the bdi dirty limit exceeded on 100 concurrent dd. CC: Chris Mason Signed-off-by: Wu Fengguang --- fs/btrfs/file.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) --- linux-next.orig/fs/btrfs/file.c 2010-12-09 12:24:59.000000000 +0800 +++ linux-next/fs/btrfs/file.c 2010-12-09 12:25:00.000000000 +0800 @@ -924,9 +924,8 @@ static ssize_t btrfs_file_aio_write(stru } iov_iter_init(&i, iov, nr_segs, count, num_written); - nrptrs = min((iov_iter_count(&i) + PAGE_CACHE_SIZE - 1) / - PAGE_CACHE_SIZE, PAGE_CACHE_SIZE / - (sizeof(struct page *))); + nrptrs = min(DIV_ROUND_UP(iov_iter_count(&i), PAGE_CACHE_SIZE), + min(16UL, PAGE_CACHE_SIZE / (sizeof(struct page *)))); pages = kmalloc(nrptrs * sizeof(struct page *), GFP_KERNEL); /* generic_write_checks can change our pos */