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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Theodore Ts'o <tytso@mit.edu>, Wu Fengguang <fengguang.wu@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jan Kara <jack@suse.cz>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Rik van Riel <riel@redhat.com>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Cc: Chris Mason <chris.mason@oracle.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: linux-mm <linux-mm@kvack.org>
Cc: <linux-fsdevel@vger.kernel.org>
Cc: LKML <linux-kernel@vger.kernel.org>
Subject: [PATCH 02/13] writeback: consolidate variable names in balance_dirty_pages()
Date: Wed, 17 Nov 2010 11:58:23 +0800	[thread overview]
Message-ID: <20101117035905.642642393@intel.com> (raw)

Andrew,
References: <20101117035821.000579293@intel.com>
Content-Disposition: inline; filename=writeback-cleanup-name-merge.patch

Lots of lenthy tests.. Let's compact the names

	*_dirty = NR_FILE_DIRTY + NR_WRITEBACK + NR_UNSTABLE_NFS

balance_dirty_pages() only cares about the above dirty sum except
in one place -- on starting background writeback.

Signed-off-by: Wu Fengguang <fengguang.wu@intel.com>
---
 mm/page-writeback.c |   26 ++++++++++++--------------
 1 file changed, 12 insertions(+), 14 deletions(-)

--- linux-next.orig/mm/page-writeback.c	2010-11-15 19:50:16.000000000 +0800
+++ linux-next/mm/page-writeback.c	2010-11-15 19:50:27.000000000 +0800
@@ -461,8 +461,8 @@ unsigned long bdi_dirty_limit(struct bac
 static void balance_dirty_pages(struct address_space *mapping,
 				unsigned long pages_dirtied)
 {
-	long nr_reclaimable, bdi_nr_reclaimable;
-	long nr_writeback, bdi_nr_writeback;
+	long nr_reclaimable;
+	long nr_dirty, bdi_dirty;  /* = file_dirty + writeback + unstable_nfs */
 	unsigned long background_thresh;
 	unsigned long dirty_thresh;
 	unsigned long bdi_thresh;
@@ -480,7 +480,7 @@ static void balance_dirty_pages(struct a
 		 */
 		nr_reclaimable = global_page_state(NR_FILE_DIRTY) +
 					global_page_state(NR_UNSTABLE_NFS);
-		nr_writeback = global_page_state(NR_WRITEBACK);
+		nr_dirty = nr_reclaimable + global_page_state(NR_WRITEBACK);
 
 		global_dirty_limits(&background_thresh, &dirty_thresh);
 
@@ -489,8 +489,7 @@ static void balance_dirty_pages(struct a
 		 * catch-up. This avoids (excessively) small writeouts
 		 * when the bdi limits are ramping up.
 		 */
-		if (nr_reclaimable + nr_writeback <=
-				(background_thresh + dirty_thresh) / 2)
+		if (nr_dirty <= (background_thresh + dirty_thresh) / 2)
 			break;
 
 		bdi_thresh = bdi_dirty_limit(bdi, dirty_thresh);
@@ -507,21 +506,21 @@ static void balance_dirty_pages(struct a
 		 * deltas.
 		 */
 		if (bdi_thresh < 2*bdi_stat_error(bdi)) {
-			bdi_nr_reclaimable = bdi_stat_sum(bdi, BDI_RECLAIMABLE);
-			bdi_nr_writeback = bdi_stat_sum(bdi, BDI_WRITEBACK);
+			bdi_dirty = bdi_stat_sum(bdi, BDI_RECLAIMABLE) +
+				    bdi_stat_sum(bdi, BDI_WRITEBACK);
 		} else {
-			bdi_nr_reclaimable = bdi_stat(bdi, BDI_RECLAIMABLE);
-			bdi_nr_writeback = bdi_stat(bdi, BDI_WRITEBACK);
+			bdi_dirty = bdi_stat(bdi, BDI_RECLAIMABLE) +
+				    bdi_stat(bdi, BDI_WRITEBACK);
 		}
 
-		if (bdi_nr_reclaimable + bdi_nr_writeback >= bdi_thresh) {
+		if (bdi_dirty >= bdi_thresh) {
 			pause = HZ/10;
 			goto pause;
 		}
 
 		bw = 100 << 20; /* use static 100MB/s for the moment */
 
-		bw = bw * (bdi_thresh - (bdi_nr_reclaimable + bdi_nr_writeback));
+		bw = bw * (bdi_thresh - bdi_dirty);
 		bw = bw / (bdi_thresh / TASK_SOFT_DIRTY_LIMIT + 1);
 
 		pause = HZ * (pages_dirtied << PAGE_CACHE_SHIFT) / (bw + 1);
@@ -537,9 +536,8 @@ pause:
 		 * bdi or process from holding back light ones; The latter is
 		 * the last resort safeguard.
 		 */
-		dirty_exceeded =
-			(bdi_nr_reclaimable + bdi_nr_writeback > bdi_thresh)
-			|| (nr_reclaimable + nr_writeback > dirty_thresh);
+		dirty_exceeded = (bdi_dirty > bdi_thresh) ||
+				  (nr_dirty > dirty_thresh);
 
 		if (!dirty_exceeded)
 			break;


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             reply	other threads:[~2010-11-17  3:58 UTC|newest]

Thread overview: 2+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-11-17  3:58 Wu Fengguang [this message]
  -- strict thread matches above, loose matches on Subject: below --
2010-11-17  4:27 [PATCH 00/13] IO-less dirty throttling v2 Wu Fengguang
2010-11-17  4:27 ` [PATCH 02/13] writeback: consolidate variable names in balance_dirty_pages() Wu Fengguang

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