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From: Mel Gorman <mel@csn.ul.ie>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Dave Chinner <david@fromorbit.com>,
	Chris Mason <chris.mason@oracle.com>,
	Nick Piggin <npiggin@suse.de>, Rik van Riel <riel@redhat.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Christoph Hellwig <hch@infradead.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 8/8] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages
Date: Tue, 27 Jul 2010 15:40:26 +0100	[thread overview]
Message-ID: <20100727144026.GC5300@csn.ul.ie> (raw)
In-Reply-To: <20100727143423.GA5057@localhost>

On Tue, Jul 27, 2010 at 10:34:23PM +0800, Wu Fengguang wrote:
> > If you plan to keep wakeup_flusher_threads(), a simpler form may be
> > sufficient, eg.
> > 
> >         laptop_mode ? 0 : (nr_dirty * 16)
> 
> This number is not sensitive because the writeback code may well round
> it up to some more IO efficient value (currently 4MB). AFAIK the
> nr_pages parameters passed by all existing flusher callers are some
> rule-of-thumb value, and far from being an exact number.
> 

I get that it's a rule of thumb but decided I would still pass in some value
related to nr_dirty that was bounded in some manner.  Currently, that bound
is 4MB but maybe it should have been bound to MAX_WRITEBACK_PAGES (which is
4MB for x86, but could be anything depending on the base page size).

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab

WARNING: multiple messages have this Message-ID (diff)
From: Mel Gorman <mel@csn.ul.ie>
To: Wu Fengguang <fengguang.wu@intel.com>
Cc: "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"linux-mm@kvack.org" <linux-mm@kvack.org>,
	Dave Chinner <david@fromorbit.com>,
	Chris Mason <chris.mason@oracle.com>,
	Nick Piggin <npiggin@suse.de>, Rik van Riel <riel@redhat.com>,
	Johannes Weiner <hannes@cmpxchg.org>,
	Christoph Hellwig <hch@infradead.org>,
	KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>,
	KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	Andrea Arcangeli <aarcange@redhat.com>
Subject: Re: [PATCH 8/8] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages
Date: Tue, 27 Jul 2010 15:40:26 +0100	[thread overview]
Message-ID: <20100727144026.GC5300@csn.ul.ie> (raw)
In-Reply-To: <20100727143423.GA5057@localhost>

On Tue, Jul 27, 2010 at 10:34:23PM +0800, Wu Fengguang wrote:
> > If you plan to keep wakeup_flusher_threads(), a simpler form may be
> > sufficient, eg.
> > 
> >         laptop_mode ? 0 : (nr_dirty * 16)
> 
> This number is not sensitive because the writeback code may well round
> it up to some more IO efficient value (currently 4MB). AFAIK the
> nr_pages parameters passed by all existing flusher callers are some
> rule-of-thumb value, and far from being an exact number.
> 

I get that it's a rule of thumb but decided I would still pass in some value
related to nr_dirty that was bounded in some manner.  Currently, that bound
is 4MB but maybe it should have been bound to MAX_WRITEBACK_PAGES (which is
4MB for x86, but could be anything depending on the base page size).

-- 
Mel Gorman
Part-time Phd Student                          Linux Technology Center
University of Limerick                         IBM Dublin Software Lab

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  reply	other threads:[~2010-07-27 14:40 UTC|newest]

Thread overview: 177+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-07-19 13:11 [PATCH 0/8] Reduce writeback from page reclaim context V4 Mel Gorman
2010-07-19 13:11 ` Mel Gorman
2010-07-19 13:11 ` [PATCH 1/8] vmscan: tracing: Roll up of patches currently in mmotm Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 13:11 ` [PATCH 2/8] vmscan: tracing: Update trace event to track if page reclaim IO is for anon or file pages Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 13:24   ` Rik van Riel
2010-07-19 13:24     ` Rik van Riel
2010-07-19 14:15   ` Christoph Hellwig
2010-07-19 14:15     ` Christoph Hellwig
2010-07-19 14:24     ` Mel Gorman
2010-07-19 14:24       ` Mel Gorman
2010-07-19 14:26       ` Christoph Hellwig
2010-07-19 14:26         ` Christoph Hellwig
2010-07-19 13:11 ` [PATCH 3/8] vmscan: tracing: Update post-processing script to distinguish between anon and file IO from page reclaim Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 13:32   ` Rik van Riel
2010-07-19 13:32     ` Rik van Riel
2010-07-19 13:11 ` [PATCH 4/8] vmscan: Do not writeback filesystem pages in direct reclaim Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 14:19   ` Christoph Hellwig
2010-07-19 14:19     ` Christoph Hellwig
2010-07-19 14:26     ` Mel Gorman
2010-07-19 14:26       ` Mel Gorman
2010-07-19 18:25   ` Rik van Riel
2010-07-19 18:25     ` Rik van Riel
2010-07-19 22:14   ` Johannes Weiner
2010-07-19 22:14     ` Johannes Weiner
2010-07-20 13:45     ` Mel Gorman
2010-07-20 13:45       ` Mel Gorman
2010-07-20 22:02       ` Johannes Weiner
2010-07-20 22:02         ` Johannes Weiner
2010-07-21 11:36         ` Johannes Weiner
2010-07-21 11:36           ` Johannes Weiner
2010-07-21 11:52         ` Mel Gorman
2010-07-21 11:52           ` Mel Gorman
2010-07-21 12:01           ` KAMEZAWA Hiroyuki
2010-07-21 12:01             ` KAMEZAWA Hiroyuki
2010-07-21 14:27             ` Mel Gorman
2010-07-21 14:27               ` Mel Gorman
2010-07-21 23:57               ` KAMEZAWA Hiroyuki
2010-07-21 23:57                 ` KAMEZAWA Hiroyuki
2010-07-22  9:19                 ` Mel Gorman
2010-07-22  9:19                   ` Mel Gorman
2010-07-22  9:22                   ` KAMEZAWA Hiroyuki
2010-07-22  9:22                     ` KAMEZAWA Hiroyuki
2010-07-21 13:04           ` Johannes Weiner
2010-07-21 13:04             ` Johannes Weiner
2010-07-21 13:38             ` Mel Gorman
2010-07-21 13:38               ` Mel Gorman
2010-07-21 14:28               ` Johannes Weiner
2010-07-21 14:28                 ` Johannes Weiner
2010-07-21 14:31                 ` Mel Gorman
2010-07-21 14:31                   ` Mel Gorman
2010-07-21 14:39                   ` Johannes Weiner
2010-07-21 14:39                     ` Johannes Weiner
2010-07-21 15:06                     ` Mel Gorman
2010-07-21 15:06                       ` Mel Gorman
2010-07-26  8:29               ` Wu Fengguang
2010-07-26  8:29                 ` Wu Fengguang
2010-07-26  9:12                 ` Mel Gorman
2010-07-26  9:12                   ` Mel Gorman
2010-07-26 11:19                   ` Wu Fengguang
2010-07-26 11:19                     ` Wu Fengguang
2010-07-26 12:53                     ` Mel Gorman
2010-07-26 12:53                       ` Mel Gorman
2010-07-26 13:03                       ` Wu Fengguang
2010-07-26 13:03                         ` Wu Fengguang
2010-07-19 13:11 ` [PATCH 5/8] fs,btrfs: Allow kswapd to writeback pages Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 18:27   ` Rik van Riel
2010-07-19 18:27     ` Rik van Riel
2010-07-19 13:11 ` [PATCH 6/8] fs,xfs: " Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 14:20   ` Christoph Hellwig
2010-07-19 14:20     ` Christoph Hellwig
2010-07-19 14:43     ` Mel Gorman
2010-07-19 14:43       ` Mel Gorman
2010-07-19 13:11 ` [PATCH 7/8] writeback: sync old inodes first in background writeback Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 14:21   ` Christoph Hellwig
2010-07-19 14:21     ` Christoph Hellwig
2010-07-19 14:40     ` Mel Gorman
2010-07-19 14:40       ` Mel Gorman
2010-07-19 14:48       ` Christoph Hellwig
2010-07-19 14:48         ` Christoph Hellwig
2010-07-22  8:52       ` Wu Fengguang
2010-07-22  8:52         ` Wu Fengguang
2010-07-22  9:02         ` Wu Fengguang
2010-07-22  9:02           ` Wu Fengguang
2010-07-22  9:21         ` Wu Fengguang
2010-07-22  9:21           ` Wu Fengguang
2010-07-22 10:48           ` Mel Gorman
2010-07-22 10:48             ` Mel Gorman
2010-07-23  9:45             ` Wu Fengguang
2010-07-23  9:45               ` Wu Fengguang
2010-07-23 10:57               ` Mel Gorman
2010-07-23 10:57                 ` Mel Gorman
2010-07-23 11:49                 ` Wu Fengguang
2010-07-23 11:49                   ` Wu Fengguang
2010-07-23 12:20                   ` Wu Fengguang
2010-07-23 12:20                     ` Wu Fengguang
2010-07-25 10:43                 ` KOSAKI Motohiro
2010-07-25 10:43                   ` KOSAKI Motohiro
2010-07-25 12:03                   ` Minchan Kim
2010-07-25 12:03                     ` Minchan Kim
2010-07-26  3:27                     ` Wu Fengguang
2010-07-26  3:27                       ` Wu Fengguang
2010-07-26  4:11                       ` Minchan Kim
2010-07-26  4:11                         ` Minchan Kim
2010-07-26  4:37                         ` Wu Fengguang
2010-07-26  4:37                           ` Wu Fengguang
2010-07-26  4:37                           ` Wu Fengguang
2010-07-26 16:30                           ` Minchan Kim
2010-07-26 16:30                             ` Minchan Kim
2010-07-26 16:30                             ` Minchan Kim
2010-07-26 22:48                             ` Wu Fengguang
2010-07-26 22:48                               ` Wu Fengguang
2010-07-26 22:48                               ` Wu Fengguang
2010-07-26  3:08                   ` Wu Fengguang
2010-07-26  3:08                     ` Wu Fengguang
2010-07-26  3:11                     ` Rik van Riel
2010-07-26  3:11                       ` Rik van Riel
2010-07-26  3:17                       ` Wu Fengguang
2010-07-26  3:17                         ` Wu Fengguang
2010-07-22 15:34           ` Minchan Kim
2010-07-22 15:34             ` Minchan Kim
2010-07-23 11:59             ` Wu Fengguang
2010-07-23 11:59               ` Wu Fengguang
2010-07-22  9:42         ` Mel Gorman
2010-07-22  9:42           ` Mel Gorman
2010-07-23  8:33           ` Wu Fengguang
2010-07-23  8:33             ` Wu Fengguang
2010-07-22  1:13     ` Wu Fengguang
2010-07-22  1:13       ` Wu Fengguang
2010-07-19 18:43   ` Rik van Riel
2010-07-19 18:43     ` Rik van Riel
2010-07-19 13:11 ` [PATCH 8/8] vmscan: Kick flusher threads to clean pages when reclaim is encountering dirty pages Mel Gorman
2010-07-19 13:11   ` Mel Gorman
2010-07-19 14:23   ` Christoph Hellwig
2010-07-19 14:23     ` Christoph Hellwig
2010-07-19 14:37     ` Mel Gorman
2010-07-19 14:37       ` Mel Gorman
2010-07-19 22:48       ` Johannes Weiner
2010-07-19 22:48         ` Johannes Weiner
2010-07-20 14:10         ` Mel Gorman
2010-07-20 14:10           ` Mel Gorman
2010-07-20 22:05           ` Johannes Weiner
2010-07-20 22:05             ` Johannes Weiner
2010-07-19 18:59   ` Rik van Riel
2010-07-19 18:59     ` Rik van Riel
2010-07-19 22:26   ` Johannes Weiner
2010-07-19 22:26     ` Johannes Weiner
2010-07-26  7:28   ` Wu Fengguang
2010-07-26  7:28     ` Wu Fengguang
2010-07-26  9:26     ` Mel Gorman
2010-07-26  9:26       ` Mel Gorman
2010-07-26 11:27       ` Wu Fengguang
2010-07-26 11:27         ` Wu Fengguang
2010-07-26 12:57         ` Mel Gorman
2010-07-26 12:57           ` Mel Gorman
2010-07-26 13:10           ` Wu Fengguang
2010-07-26 13:10             ` Wu Fengguang
2010-07-27 13:35             ` Mel Gorman
2010-07-27 13:35               ` Mel Gorman
2010-07-27 14:24               ` Wu Fengguang
2010-07-27 14:24                 ` Wu Fengguang
2010-07-27 14:34                 ` Wu Fengguang
2010-07-27 14:34                   ` Wu Fengguang
2010-07-27 14:40                   ` Mel Gorman [this message]
2010-07-27 14:40                     ` Mel Gorman
2010-07-27 14:55                     ` Wu Fengguang
2010-07-27 14:55                       ` Wu Fengguang
2010-07-27 14:38                 ` Mel Gorman
2010-07-27 14:38                   ` Mel Gorman
2010-07-27 15:21                   ` Wu Fengguang
2010-07-27 15:21                     ` Wu Fengguang

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