From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH 25/35] btrfs: lower the dirty balacing rate limit Date: Mon, 13 Dec 2010 22:47:11 +0800 Message-ID: <20101213150329.351105237@intel.com> References: <20101213144646.341970461@intel.com> Cc: Jan Kara , Chris Mason , Wu Fengguang To: Andrew Morton Return-path: 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 Content-Disposition: inline; filename=btrfs-limit-nr-dirtied.patch Sender: owner-linux-mm@kvack.org List-Id: linux-fsdevel.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 2010-12-13 21:46:19.000000000 +0800 +++ linux-next/fs/btrfs/file.c 2010-12-13 21:46:20.000000000 +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 */ -- 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/ . Fight unfair telecom policy in Canada: sign http://dissolvethecrtc.ca/ Don't email: email@kvack.org