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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>, Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 18/18] writeback: rearrange the wb_writeback() loop
Date: Tue, 24 May 2011 13:14:29 +0800	[thread overview]
Message-ID: <20110524051900.458087722@intel.com> (raw)
In-Reply-To: 20110524051411.924582719@intel.com

[-- Attachment #1: loop-cleanup --]
[-- Type: text/plain, Size: 2851 bytes --]

Move the terminate conditions to the end of the loop, and move the
work->older_than_this updates close to each others.

Proposed-by: Dave Chinner <david@fromorbit.com>
Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 fs/fs-writeback.c |   58 +++++++++++++++++++++++---------------------
 1 file changed, 31 insertions(+), 27 deletions(-)

--- linux-next.orig/fs/fs-writeback.c	2011-05-24 11:17:28.000000000 +0800
+++ linux-next/fs/fs-writeback.c	2011-05-24 11:17:30.000000000 +0800
@@ -713,42 +713,22 @@ static long wb_writeback(struct bdi_writ
 	unsigned long oldest_jif;
 	struct inode *inode;
 	long progress;
+	bool bg_retry_all = false;
 
 	oldest_jif = jiffies;
 	work->older_than_this = &oldest_jif;
 
 	spin_lock(&wb->list_lock);
 	for (;;) {
-		/*
-		 * Stop writeback when nr_pages has been consumed
-		 */
-		if (work->nr_pages <= 0)
-			break;
-
-		/*
-		 * Background writeout and kupdate-style writeback may
-		 * run forever. Stop them if there is other work to do
-		 * so that e.g. sync can proceed. They'll be restarted
-		 * after the other works are all done.
-		 */
-		if ((work->for_background || work->for_kupdate) &&
-		    !list_empty(&wb->bdi->work_list))
-			break;
-
-		/*
-		 * For background writeout, stop when we are below the
-		 * background dirty threshold
-		 */
-		if (work->for_background && !over_bground_thresh())
-			break;
-
-		if (work->for_kupdate || work->for_background) {
+		if (bg_retry_all) {
+			bg_retry_all = false;
+			work->older_than_this = NULL;
+		} else if (work->for_kupdate || work->for_background) {
 			oldest_jif = jiffies -
 				msecs_to_jiffies(dirty_expire_interval * 10);
 			work->older_than_this = &oldest_jif;
 		}
 
-retry:
 		trace_writeback_start(wb->bdi, work);
 		if (list_empty(&wb->b_io))
 			queue_io(wb, work->older_than_this);
@@ -778,14 +758,38 @@ retry:
 		    work->older_than_this &&
 		    list_empty(&wb->b_io) &&
 		    list_empty(&wb->b_more_io)) {
-			work->older_than_this = NULL;
-			goto retry;
+			bg_retry_all = true;
+			continue;
 		}
 		/*
 		 * No more inodes for IO, bail
 		 */
 		if (list_empty(&wb->b_more_io))
 			break;
+
+		/*
+		 * Stop writeback when nr_pages has been consumed
+		 */
+		if (work->nr_pages <= 0)
+			break;
+
+		/*
+		 * For background writeout, stop when we are below the
+		 * background dirty threshold
+		 */
+		if (work->for_background && !over_bground_thresh())
+			break;
+
+		/*
+		 * Background writeout and kupdate-style writeback may
+		 * run forever. Stop them if there is other work to do
+		 * so that e.g. sync can proceed. They'll be restarted
+		 * after the other works are all done.
+		 */
+		if ((work->for_background || work->for_kupdate) &&
+		    !list_empty(&wb->bdi->work_list))
+			break;
+
 		/*
 		 * Nothing written. Wait for some inode to
 		 * become available for writeback. Otherwise

  parent reply	other threads:[~2011-05-24  5:14 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-05-24  5:14 [PATCH 00/18] writeback fixes and cleanups for 2.6.40 (v4) Wu Fengguang
2011-05-24  5:14 ` [PATCH 01/18] writeback: introduce .tagged_writepages for the WB_SYNC_NONE sync stage Wu Fengguang
2011-05-24  5:14 ` [PATCH 02/18] writeback: update dirtied_when for synced inode to prevent livelock Wu Fengguang
2011-05-24  5:14 ` [PATCH 03/18] writeback: introduce writeback_control.inodes_cleaned Wu Fengguang
2011-05-24  5:14 ` [PATCH 04/18] writeback: try more writeback as long as something was written Wu Fengguang
2011-05-24  5:14 ` [PATCH 05/18] writeback: the kupdate expire timestamp should be a moving target Wu Fengguang
2011-05-24  5:14 ` [PATCH 06/18] writeback: sync expired inodes first in background writeback Wu Fengguang
2011-05-24 15:52   ` Jan Kara
2011-05-25 14:38     ` Wu Fengguang
2011-05-26 23:10       ` Jan Kara
2011-05-27 15:06         ` Wu Fengguang
2011-05-27 15:17       ` Wu Fengguang
2011-05-24  5:14 ` [PATCH 07/18] writeback: refill b_io iff empty Wu Fengguang
2011-05-24  5:14 ` [PATCH 08/18] writeback: split inode_wb_list_lock into bdi_writeback.list_lock Wu Fengguang
2011-05-24  5:14 ` [PATCH 09/18] writeback: elevate queue_io() into wb_writeback() Wu Fengguang
2011-05-24  5:14 ` [PATCH 10/18] writeback: avoid extra sync work at enqueue time Wu Fengguang
2011-05-24  5:14 ` [PATCH 11/18] writeback: add bdi_dirty_limit() kernel-doc Wu Fengguang
2011-05-24  5:14 ` [PATCH 12/18] writeback: skip balance_dirty_pages() for in-memory fs Wu Fengguang
2011-05-24  5:14 ` [PATCH 13/18] writeback: remove writeback_control.more_io Wu Fengguang
2011-05-24  5:14 ` [PATCH 14/18] writeback: remove .nonblocking and .encountered_congestion Wu Fengguang
2011-05-24  5:14 ` [PATCH 15/18] writeback: trace event writeback_single_inode Wu Fengguang
2011-05-24  5:14 ` [PATCH 16/18] writeback: trace event writeback_queue_io Wu Fengguang
2011-05-24  5:14 ` [PATCH 17/18] writeback: make writeback_control.nr_to_write straight Wu Fengguang
2011-05-24  5:14 ` Wu Fengguang [this message]
2011-05-29  7:34 ` [PATCH 00/18] writeback fixes and cleanups for 2.6.40 (v4) Sedat Dilek
  -- strict thread matches above, loose matches on Subject: below --
2011-05-19 21:45 [PATCH 00/18] writeback fixes and cleanups for 2.6.40 (v3) Wu Fengguang
2011-05-19 21:45 ` [PATCH 18/18] writeback: rearrange the wb_writeback() loop Wu Fengguang

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