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From: Wu Fengguang <fengguang.wu@intel.com>
To: Jan Kara <jack@suse.cz>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	Christoph Hellwig <hch@infradead.org>,
	Dave Chinner <david@fromorbit.com>
Subject: Re: [PATCH 1/2] writeback: Improve busyloop prevention
Date: Sat, 15 Oct 2011 20:41:36 +0800	[thread overview]
Message-ID: <20111015124136.GA8914@localhost> (raw)
In-Reply-To: <20111014160047.GA13330@localhost>

> 2) the flusher thread is not woken up because we test writeback_in_progress()
>    in balance_dirty_pages().
> 
>                 if (unlikely(!writeback_in_progress(bdi)))
>                         bdi_start_background_writeback(bdi);
> 
[...]
> This should be fixable by removing the BDI_writeback_running flag
> before doing the wait sleep.

I tried adding the below patch, and this time it shows 1.8%
performance improvement.  Looks not bad :-)

     3.1.0-rc8-ioless6a+  3.1.0-rc8-ioless6-requeue7+
------------------------  ------------------------
                   32.09        +1.1%        32.45  thresh=1M/ext4-10dd-4k-8p-4096M-1M:10-X
                   51.36        +3.2%        53.00  thresh=1M/ext4-1dd-4k-8p-4096M-1M:10-X
                   46.93        +1.9%        47.80  thresh=1M/ext4-2dd-4k-8p-4096M-1M:10-X
                   28.68        +1.6%        29.15  thresh=1M/xfs-10dd-4k-8p-4096M-1M:10-X
                   51.95        +4.2%        54.13  thresh=1M/xfs-1dd-4k-8p-4096M-1M:10-X
                   47.07        +1.5%        47.80  thresh=1M/xfs-2dd-4k-8p-4096M-1M:10-X
                   54.37        +2.2%        55.58  thresh=8M/btrfs-10dd-4k-8p-4096M-8M:10-X
                   56.12        +4.2%        58.49  thresh=8M/btrfs-1dd-4k-8p-4096M-8M:10-X
                   56.22        +2.4%        57.55  thresh=8M/btrfs-2dd-4k-8p-4096M-8M:10-X
                   32.21        +1.7%        32.77  thresh=8M/ext3-10dd-4k-8p-4096M-8M:10-X
                   45.37        +2.7%        46.58  thresh=8M/ext3-1dd-4k-8p-4096M-8M:10-X
                   43.71        +2.6%        44.83  thresh=8M/ext3-2dd-4k-8p-4096M-8M:10-X
                   35.58        +1.3%        36.06  thresh=8M/ext4-10dd-4k-8p-4096M-8M:10-X
                   56.39        +0.4%        56.61  thresh=8M/ext4-1dd-4k-8p-4096M-8M:10-X
                   51.26        +1.4%        51.98  thresh=8M/ext4-2dd-4k-8p-4096M-8M:10-X
                   31.07        +0.3%        31.16  thresh=8M/xfs-10dd-4k-8p-4096M-8M:10-X
                   55.44        -2.0%        54.33  thresh=8M/xfs-1dd-4k-8p-4096M-8M:10-X
                   47.59        +0.6%        47.87  thresh=8M/xfs-2dd-4k-8p-4096M-8M:10-X
                  823.40        +1.8%       838.14  TOTAL

--- linux-next.orig/fs/fs-writeback.c	2011-10-15 08:30:48.000000000 +0800
+++ linux-next/fs/fs-writeback.c	2011-10-15 08:31:36.000000000 +0800
@@ -809,8 +809,10 @@ static long wb_writeback(struct bdi_writ
 			break;
 		trace_writeback_wait(wb->bdi, work);
 		spin_unlock(&wb->list_lock);
+		clear_bit(BDI_writeback_running, &wb->bdi->state);
 		__set_current_state(TASK_INTERRUPTIBLE);
 		schedule_timeout(pause);
+		set_bit(BDI_writeback_running, &wb->bdi->state);
 		if (pause < max_pause)
 			pause <<= 1;
 		spin_lock(&wb->list_lock);

  parent reply	other threads:[~2011-10-15 12:41 UTC|newest]

Thread overview: 43+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2011-10-12 20:57 [PATCH 0/2 v4] writeback: Improve busyloop prevention and inode requeueing Jan Kara
2011-10-12 20:57 ` [PATCH 1/2] writeback: Improve busyloop prevention Jan Kara
2011-10-13 14:26   ` Wu Fengguang
2011-10-13 20:13     ` Jan Kara
2011-10-14  7:18       ` Christoph Hellwig
2011-10-14 19:31         ` Chris Mason
     [not found]     ` <20111013143939.GA9691@localhost>
2011-10-13 20:18       ` Jan Kara
2011-10-14 16:00         ` Wu Fengguang
2011-10-14 16:28           ` Wu Fengguang
2011-10-18  0:51             ` Jan Kara
2011-10-18 14:35               ` Wu Fengguang
2011-10-19 11:56                 ` Jan Kara
2011-10-19 13:25                   ` Wu Fengguang
2011-10-19 13:30                   ` Wu Fengguang
2011-10-19 13:35                   ` Wu Fengguang
2011-10-20 12:09                   ` Wu Fengguang
2011-10-20 12:33                     ` Wu Fengguang
2011-10-20 13:39                       ` Wu Fengguang
2011-10-20 22:26                         ` Jan Kara
2011-10-22  4:20                           ` Wu Fengguang
2011-10-24 15:45                             ` Jan Kara
     [not found]                           ` <20111027063133.GA10146@localhost>
2011-10-27 20:31                             ` Jan Kara
     [not found]                               ` <20111101134231.GA31718@localhost>
2011-11-01 21:53                                 ` Jan Kara
2011-11-02 17:25                                   ` Wu Fengguang
     [not found]                               ` <20111102185603.GA4034@localhost>
2011-11-03  1:51                                 ` Jan Kara
2011-11-03 14:52                                   ` Wu Fengguang
     [not found]                                   ` <20111104152054.GA11577@localhost>
2011-11-08 23:52                                     ` Jan Kara
2011-11-09 13:51                                       ` Wu Fengguang
2011-11-10 14:50                                       ` Jan Kara
2011-12-05  8:02                                         ` Wu Fengguang
2011-12-07 10:13                                           ` Jan Kara
2011-12-07 11:45                                             ` Wu Fengguang
     [not found]                           ` <20111027064745.GA14017@localhost>
2011-10-27 20:50                             ` Jan Kara
2011-10-20  9:46               ` Christoph Hellwig
2011-10-20 15:32                 ` Jan Kara
2011-10-15 12:41           ` Wu Fengguang [this message]
2011-10-12 20:57 ` [PATCH 2/2] writeback: Replace some redirty_tail() calls with requeue_io() Jan Kara
2011-10-13 14:30   ` Wu Fengguang
2011-10-13 14:15 ` [PATCH 0/2 v4] writeback: Improve busyloop prevention and inode requeueing Wu Fengguang
  -- strict thread matches above, loose matches on Subject: below --
2011-10-05 17:58 [PATCH 0/2] Avoid putting of writeback of inodes for too long (v3) Jan Kara
2011-10-05 17:58 ` [PATCH 1/2] writeback: Improve busyloop prevention Jan Kara
2011-09-08  0:44 Jan Kara
2011-09-08  0:57 ` Wu Fengguang
2011-09-08 13:49   ` Jan Kara

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