From mboxrd@z Thu Jan 1 00:00:00 1970 From: Wu Fengguang Subject: [PATCH 26/35] btrfs: wait on too many nr_async_bios Date: Mon, 13 Dec 2010 22:47:12 +0800 Message-ID: <20101213150329.473271564@intel.com> References: <20101213144646.341970461@intel.com> Return-path: Received: from kanga.kvack.org ([205.233.56.17]) by lo.gmane.org with esmtp (Exim 4.69) (envelope-from ) id 1PSA2R-0002El-5D for glkm-linux-mm-2@m.gmane.org; Mon, 13 Dec 2010 16:10:07 +0100 Received: from mail203.messagelabs.com (mail203.messagelabs.com [216.82.254.243]) by kanga.kvack.org (Postfix) with SMTP id AA3266B00AB for ; Mon, 13 Dec 2010 10:08:51 -0500 (EST) Content-Disposition: inline; filename=btrfs-nr_async_bios-wait.patch Sender: owner-linux-mm@kvack.org To: Andrew Morton Cc: Jan Kara , Wu Fengguang , Christoph Hellwig , Trond Myklebust , Dave Chinner , Theodore Ts'o , Chris Mason , Peter Zijlstra , Mel Gorman , Rik van Riel , KOSAKI Motohiro , Greg Thelen , Minchan Kim , linux-mm , linux-fsdevel@vger.kernel.org, LKML List-Id: linux-mm.kvack.org Tests show that btrfs is repeatedly moving _all_ PG_dirty pages into PG_writeback state. It's desirable to have some limit on the number of writeback pages. Signed-off-by: Wu Fengguang --- fs/btrfs/disk-io.c | 7 +++++++ 1 file changed, 7 insertions(+) before patch: http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/tests/3G/btrfs-1dd-1M-8p-2952M-2.6.37-rc5+-2010-12-08-21-30/vmstat-dirty-300.png after patch: http://www.kernel.org/pub/linux/kernel/people/wfg/writeback/tests/3G/btrfs-1dd-1M-8p-2952M-2.6.37-rc5+-2010-12-08-21-14/vmstat-dirty-300.png --- linux-next.orig/fs/btrfs/disk-io.c 2010-12-13 21:45:55.000000000 +0800 +++ linux-next/fs/btrfs/disk-io.c 2010-12-13 21:46:20.000000000 +0800 @@ -590,6 +590,7 @@ int btrfs_wq_submit_bio(struct btrfs_fs_ extent_submit_bio_hook_t *submit_bio_done) { struct async_submit_bio *async; + int limit; async = kmalloc(sizeof(*async), GFP_NOFS); if (!async) @@ -617,6 +618,12 @@ int btrfs_wq_submit_bio(struct btrfs_fs_ btrfs_queue_worker(&fs_info->workers, &async->work); + limit = btrfs_async_submit_limit(fs_info); + + if (atomic_read(&fs_info->nr_async_bios) > limit) + wait_event(fs_info->async_submit_wait, + (atomic_read(&fs_info->nr_async_bios) < limit)); + while (atomic_read(&fs_info->async_submit_draining) && atomic_read(&fs_info->nr_async_submits)) { wait_event(fs_info->async_submit_wait, -- 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