From: Wu Fengguang <fengguang.wu@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@lst.de>,
Dave Chinner <david@fromorbit.com>,
Greg Thelen <gthelen@google.com>,
Minchan Kim <minchan.kim@gmail.com>,
Vivek Goyal <vgoyal@redhat.com>,
Andrea Righi <arighi@develer.com>, linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] writeback: dirty position control
Date: Tue, 9 Aug 2011 06:47:42 +0800 [thread overview]
Message-ID: <20110808224742.GB7176@localhost> (raw)
In-Reply-To: <1312813909.10488.38.camel@twins>
On Mon, Aug 08, 2011 at 10:31:49PM +0800, Peter Zijlstra wrote:
> On Mon, 2011-08-08 at 22:11 +0800, Wu Fengguang wrote:
> > It's actually dead code because (origin < limit) should never happen.
> > I feel so good being able to drop 5 more lines of code :)
>
> OK, but that leaves me trying to figure out what origin is, and why its
> 4 * thresh.
origin is where the control line crosses the X axis (in both the
global/bdi setpoint cases).
"4 * thresh" is merely something larger than max(dirty, thresh)
that yields reasonably gentle slope. The more slope, the larger
"gravity" to bring the dirty pages back to the setpoint.
> I'm having a horrible time understanding this stuff.
Sorry for that. Do you have more questions?
Thanks,
Fengguang
WARNING: multiple messages have this Message-ID (diff)
From: Wu Fengguang <fengguang.wu@intel.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: "linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
Andrew Morton <akpm@linux-foundation.org>,
Jan Kara <jack@suse.cz>, Christoph Hellwig <hch@lst.de>,
Dave Chinner <david@fromorbit.com>,
Greg Thelen <gthelen@google.com>,
Minchan Kim <minchan.kim@gmail.com>,
Vivek Goyal <vgoyal@redhat.com>,
Andrea Righi <arighi@develer.com>, linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>
Subject: Re: [PATCH 2/5] writeback: dirty position control
Date: Tue, 9 Aug 2011 06:47:42 +0800 [thread overview]
Message-ID: <20110808224742.GB7176@localhost> (raw)
In-Reply-To: <1312813909.10488.38.camel@twins>
On Mon, Aug 08, 2011 at 10:31:49PM +0800, Peter Zijlstra wrote:
> On Mon, 2011-08-08 at 22:11 +0800, Wu Fengguang wrote:
> > It's actually dead code because (origin < limit) should never happen.
> > I feel so good being able to drop 5 more lines of code :)
>
> OK, but that leaves me trying to figure out what origin is, and why its
> 4 * thresh.
origin is where the control line crosses the X axis (in both the
global/bdi setpoint cases).
"4 * thresh" is merely something larger than max(dirty, thresh)
that yields reasonably gentle slope. The more slope, the larger
"gravity" to bring the dirty pages back to the setpoint.
> I'm having a horrible time understanding this stuff.
Sorry for that. Do you have more questions?
Thanks,
Fengguang
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next prev parent reply other threads:[~2011-08-08 22:47 UTC|newest]
Thread overview: 305+ messages / expand[flat|nested] mbox.gz Atom feed top
2011-08-06 8:44 [PATCH 0/5] IO-less dirty throttling v8 Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` [PATCH 1/5] writeback: account per-bdi accumulated dirtied pages Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` [PATCH 2/5] writeback: dirty position control Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-08 13:46 ` Peter Zijlstra
2011-08-08 13:46 ` Peter Zijlstra
2011-08-08 13:46 ` Peter Zijlstra
2011-08-08 14:11 ` Wu Fengguang
2011-08-08 14:11 ` Wu Fengguang
2011-08-08 14:31 ` Peter Zijlstra
2011-08-08 14:31 ` Peter Zijlstra
2011-08-08 14:31 ` Peter Zijlstra
2011-08-08 22:47 ` Wu Fengguang [this message]
2011-08-08 22:47 ` Wu Fengguang
2011-08-09 9:31 ` Peter Zijlstra
2011-08-09 9:31 ` Peter Zijlstra
2011-08-09 9:31 ` Peter Zijlstra
2011-08-10 12:28 ` Wu Fengguang
2011-08-10 12:28 ` Wu Fengguang
2011-08-08 14:41 ` Peter Zijlstra
2011-08-08 14:41 ` Peter Zijlstra
2011-08-08 14:41 ` Peter Zijlstra
2011-08-08 23:05 ` Wu Fengguang
2011-08-08 23:05 ` Wu Fengguang
2011-08-09 10:32 ` Peter Zijlstra
2011-08-09 10:32 ` Peter Zijlstra
2011-08-09 10:32 ` Peter Zijlstra
2011-08-09 17:20 ` Peter Zijlstra
2011-08-09 17:20 ` Peter Zijlstra
2011-08-09 17:20 ` Peter Zijlstra
2011-08-10 22:34 ` Jan Kara
2011-08-10 22:34 ` Jan Kara
2011-08-11 2:29 ` Wu Fengguang
2011-08-11 2:29 ` Wu Fengguang
2011-08-11 11:14 ` Jan Kara
2011-08-11 11:14 ` Jan Kara
2011-08-16 8:35 ` Wu Fengguang
2011-08-16 8:35 ` Wu Fengguang
2011-08-12 13:19 ` Wu Fengguang
2011-08-12 13:19 ` Wu Fengguang
2011-08-10 21:40 ` Vivek Goyal
2011-08-10 21:40 ` Vivek Goyal
2011-08-16 8:55 ` Wu Fengguang
2011-08-16 8:55 ` Wu Fengguang
2011-08-11 22:56 ` Peter Zijlstra
2011-08-11 22:56 ` Peter Zijlstra
2011-08-11 22:56 ` Peter Zijlstra
2011-08-12 2:43 ` Wu Fengguang
2011-08-12 2:43 ` Wu Fengguang
2011-08-12 3:18 ` Wu Fengguang
2011-08-12 5:45 ` Wu Fengguang
2011-08-12 5:45 ` Wu Fengguang
2011-08-12 9:45 ` Peter Zijlstra
2011-08-12 9:45 ` Peter Zijlstra
2011-08-12 9:45 ` Peter Zijlstra
2011-08-12 11:07 ` Wu Fengguang
2011-08-12 11:07 ` Wu Fengguang
2011-08-12 12:17 ` Peter Zijlstra
2011-08-12 12:17 ` Peter Zijlstra
2011-08-12 12:17 ` Peter Zijlstra
2011-08-12 9:47 ` Peter Zijlstra
2011-08-12 9:47 ` Peter Zijlstra
2011-08-12 9:47 ` Peter Zijlstra
2011-08-12 11:11 ` Wu Fengguang
2011-08-12 11:11 ` Wu Fengguang
2011-08-12 12:54 ` Peter Zijlstra
2011-08-12 12:54 ` Peter Zijlstra
2011-08-12 12:54 ` Peter Zijlstra
2011-08-12 12:59 ` Wu Fengguang
2011-08-12 12:59 ` Wu Fengguang
2011-08-12 13:08 ` Peter Zijlstra
2011-08-12 13:08 ` Peter Zijlstra
2011-08-12 13:08 ` Peter Zijlstra
2011-08-12 13:04 ` Peter Zijlstra
2011-08-12 13:04 ` Peter Zijlstra
2011-08-12 13:04 ` Peter Zijlstra
2011-08-12 14:20 ` Wu Fengguang
2011-08-12 14:20 ` Wu Fengguang
2011-08-22 15:38 ` Peter Zijlstra
2011-08-22 15:38 ` Peter Zijlstra
2011-08-22 15:38 ` Peter Zijlstra
2011-08-23 3:40 ` Wu Fengguang
2011-08-23 3:40 ` Wu Fengguang
2011-08-23 10:01 ` Peter Zijlstra
2011-08-23 10:01 ` Peter Zijlstra
2011-08-23 10:01 ` Peter Zijlstra
2011-08-23 14:15 ` Wu Fengguang
2011-08-23 14:15 ` Wu Fengguang
2011-08-23 17:47 ` Vivek Goyal
2011-08-23 17:47 ` Vivek Goyal
2011-08-24 0:12 ` Wu Fengguang
2011-08-24 0:12 ` Wu Fengguang
2011-08-24 16:12 ` Peter Zijlstra
2011-08-24 16:12 ` Peter Zijlstra
2011-08-26 0:18 ` Wu Fengguang
2011-08-26 0:18 ` Wu Fengguang
2011-08-26 9:04 ` Peter Zijlstra
2011-08-26 9:04 ` Peter Zijlstra
2011-08-26 10:04 ` Wu Fengguang
2011-08-26 10:04 ` Wu Fengguang
2011-08-26 10:42 ` Peter Zijlstra
2011-08-26 10:42 ` Peter Zijlstra
2011-08-26 10:52 ` Wu Fengguang
2011-08-26 10:52 ` Wu Fengguang
2011-08-26 11:26 ` Wu Fengguang
2011-08-26 12:11 ` Peter Zijlstra
2011-08-26 12:11 ` Peter Zijlstra
2011-08-26 12:20 ` Wu Fengguang
2011-08-26 12:20 ` Wu Fengguang
2011-08-26 13:13 ` Wu Fengguang
2011-08-26 13:18 ` Peter Zijlstra
2011-08-26 13:18 ` Peter Zijlstra
2011-08-26 13:24 ` Wu Fengguang
2011-08-26 13:24 ` Wu Fengguang
2011-08-24 18:00 ` Vivek Goyal
2011-08-24 18:00 ` Vivek Goyal
2011-08-25 3:19 ` Wu Fengguang
2011-08-25 3:19 ` Wu Fengguang
2011-08-25 22:20 ` Vivek Goyal
2011-08-25 22:20 ` Vivek Goyal
2011-08-26 1:56 ` Wu Fengguang
2011-08-26 1:56 ` Wu Fengguang
2011-08-26 8:56 ` Peter Zijlstra
2011-08-26 8:56 ` Peter Zijlstra
2011-08-26 9:53 ` Wu Fengguang
2011-08-26 9:53 ` Wu Fengguang
2011-08-29 13:12 ` Peter Zijlstra
2011-08-29 13:12 ` Peter Zijlstra
2011-08-29 13:37 ` Wu Fengguang
2011-08-29 13:37 ` Wu Fengguang
2011-09-02 12:16 ` Peter Zijlstra
2011-09-02 12:16 ` Peter Zijlstra
2011-09-06 12:40 ` Peter Zijlstra
2011-09-06 12:40 ` Peter Zijlstra
2011-08-24 15:57 ` Peter Zijlstra
2011-08-24 15:57 ` Peter Zijlstra
2011-08-24 15:57 ` Peter Zijlstra
2011-08-25 5:30 ` Wu Fengguang
2011-08-25 5:30 ` Wu Fengguang
2011-08-23 14:36 ` Vivek Goyal
2011-08-23 14:36 ` Vivek Goyal
2011-08-09 2:08 ` Vivek Goyal
2011-08-09 2:08 ` Vivek Goyal
2011-08-16 8:59 ` Wu Fengguang
2011-08-16 8:59 ` Wu Fengguang
2011-08-06 8:44 ` [PATCH 3/5] writeback: dirty rate control Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-09 14:54 ` Vivek Goyal
2011-08-09 14:54 ` Vivek Goyal
2011-08-11 3:42 ` Wu Fengguang
2011-08-11 3:42 ` Wu Fengguang
2011-08-09 14:57 ` Peter Zijlstra
2011-08-09 14:57 ` Peter Zijlstra
2011-08-09 14:57 ` Peter Zijlstra
2011-08-10 11:07 ` Wu Fengguang
2011-08-10 11:07 ` Wu Fengguang
2011-08-10 16:17 ` Peter Zijlstra
2011-08-10 16:17 ` Peter Zijlstra
2011-08-10 16:17 ` Peter Zijlstra
2011-08-15 14:08 ` Wu Fengguang
2011-08-15 14:08 ` Wu Fengguang
2011-08-09 15:50 ` Vivek Goyal
2011-08-09 15:50 ` Vivek Goyal
2011-08-09 16:16 ` Peter Zijlstra
2011-08-09 16:16 ` Peter Zijlstra
2011-08-09 16:16 ` Peter Zijlstra
2011-08-09 16:19 ` Peter Zijlstra
2011-08-09 16:19 ` Peter Zijlstra
2011-08-09 16:19 ` Peter Zijlstra
2011-08-10 14:07 ` Wu Fengguang
2011-08-10 14:07 ` Wu Fengguang
2011-08-10 14:00 ` Wu Fengguang
2011-08-10 14:00 ` Wu Fengguang
2011-08-10 17:10 ` Peter Zijlstra
2011-08-10 17:10 ` Peter Zijlstra
2011-08-15 14:11 ` Wu Fengguang
2011-08-15 14:11 ` Wu Fengguang
2011-08-09 16:56 ` Peter Zijlstra
2011-08-09 16:56 ` Peter Zijlstra
2011-08-09 16:56 ` Peter Zijlstra
2011-08-10 14:10 ` Wu Fengguang
2011-08-09 17:02 ` Peter Zijlstra
2011-08-09 17:02 ` Peter Zijlstra
2011-08-09 17:02 ` Peter Zijlstra
2011-08-10 14:15 ` Wu Fengguang
2011-08-10 14:15 ` Wu Fengguang
2011-08-06 8:44 ` [PATCH 4/5] writeback: per task dirty rate limit Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 14:35 ` Andrea Righi
2011-08-06 14:35 ` Andrea Righi
2011-08-07 6:19 ` Wu Fengguang
2011-08-07 6:19 ` Wu Fengguang
2011-08-08 13:47 ` Peter Zijlstra
2011-08-08 13:47 ` Peter Zijlstra
2011-08-08 13:47 ` Peter Zijlstra
2011-08-08 14:21 ` Wu Fengguang
2011-08-08 14:21 ` Wu Fengguang
2011-08-08 23:32 ` Wu Fengguang
2011-08-08 23:32 ` Wu Fengguang
2011-08-08 14:23 ` Wu Fengguang
2011-08-08 14:23 ` Wu Fengguang
2011-08-08 14:26 ` Peter Zijlstra
2011-08-08 14:26 ` Peter Zijlstra
2011-08-08 14:26 ` Peter Zijlstra
2011-08-08 22:38 ` Wu Fengguang
2011-08-08 22:38 ` Wu Fengguang
2011-08-13 16:28 ` Andrea Righi
2011-08-13 16:28 ` Andrea Righi
2011-08-15 14:21 ` Wu Fengguang
2011-08-15 14:26 ` Andrea Righi
2011-08-15 14:26 ` Andrea Righi
2011-08-09 17:46 ` Vivek Goyal
2011-08-09 17:46 ` Vivek Goyal
2011-08-10 3:29 ` Wu Fengguang
2011-08-10 3:29 ` Wu Fengguang
2011-08-10 18:18 ` Vivek Goyal
2011-08-10 18:18 ` Vivek Goyal
2011-08-11 0:55 ` Wu Fengguang
2011-08-11 0:55 ` Wu Fengguang
2011-08-09 18:35 ` Peter Zijlstra
2011-08-09 18:35 ` Peter Zijlstra
2011-08-09 18:35 ` Peter Zijlstra
2011-08-10 3:40 ` Wu Fengguang
2011-08-10 3:40 ` Wu Fengguang
2011-08-10 10:25 ` Peter Zijlstra
2011-08-10 10:25 ` Peter Zijlstra
2011-08-10 10:25 ` Peter Zijlstra
2011-08-10 11:13 ` Wu Fengguang
2011-08-10 11:13 ` Wu Fengguang
2011-08-06 8:44 ` [PATCH 5/5] writeback: IO-less balance_dirty_pages() Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 8:44 ` Wu Fengguang
2011-08-06 14:48 ` Andrea Righi
2011-08-06 14:48 ` Andrea Righi
2011-08-06 14:48 ` Andrea Righi
2011-08-07 6:44 ` Wu Fengguang
2011-08-07 6:44 ` Wu Fengguang
2011-08-07 6:44 ` Wu Fengguang
2011-08-06 16:46 ` Andrea Righi
2011-08-06 16:46 ` Andrea Righi
2011-08-07 7:18 ` Wu Fengguang
2011-08-07 9:50 ` Andrea Righi
2011-08-07 9:50 ` Andrea Righi
2011-08-09 18:15 ` Vivek Goyal
2011-08-09 18:15 ` Vivek Goyal
2011-08-09 18:41 ` Peter Zijlstra
2011-08-09 18:41 ` Peter Zijlstra
2011-08-09 18:41 ` Peter Zijlstra
2011-08-10 3:22 ` Wu Fengguang
2011-08-10 3:22 ` Wu Fengguang
2011-08-10 3:26 ` Wu Fengguang
2011-08-10 3:26 ` Wu Fengguang
2011-08-09 19:16 ` Vivek Goyal
2011-08-09 19:16 ` Vivek Goyal
2011-08-10 4:33 ` Wu Fengguang
2011-08-09 2:01 ` [PATCH 0/5] IO-less dirty throttling v8 Vivek Goyal
2011-08-09 2:01 ` Vivek Goyal
2011-08-09 5:55 ` Dave Chinner
2011-08-09 5:55 ` Dave Chinner
2011-08-09 14:04 ` Vivek Goyal
2011-08-09 14:04 ` Vivek Goyal
2011-08-10 7:41 ` Greg Thelen
2011-08-10 7:41 ` Greg Thelen
2011-08-10 7:41 ` Greg Thelen
2011-08-10 18:40 ` Vivek Goyal
2011-08-10 18:40 ` Vivek Goyal
2011-08-10 18:40 ` Vivek Goyal
2011-08-11 3:21 ` Wu Fengguang
2011-08-11 3:21 ` Wu Fengguang
2011-08-11 20:42 ` Vivek Goyal
2011-08-11 20:42 ` Vivek Goyal
2011-08-11 21:00 ` Vivek Goyal
2011-08-11 21:00 ` Vivek Goyal
2011-08-16 2:20 [PATCH 0/5] IO-less dirty throttling v9 Wu Fengguang
2011-08-16 2:20 ` [PATCH 2/5] writeback: dirty position control Wu Fengguang
2011-08-16 2:20 ` Wu Fengguang
2011-08-16 2:20 ` Wu Fengguang
2011-08-16 19:41 ` Jan Kara
2011-08-16 19:41 ` Jan Kara
2011-08-17 13:23 ` Wu Fengguang
2011-08-17 13:49 ` Wu Fengguang
2011-08-17 13:49 ` Wu Fengguang
2011-08-17 20:24 ` Jan Kara
2011-08-17 20:24 ` Jan Kara
2011-08-18 4:18 ` Wu Fengguang
2011-08-18 4:18 ` Wu Fengguang
2011-08-18 4:41 ` Wu Fengguang
2011-08-18 4:41 ` Wu Fengguang
2011-08-18 19:16 ` Jan Kara
2011-08-18 19:16 ` Jan Kara
2011-08-24 3:16 ` Wu Fengguang
2011-08-24 3:16 ` Wu Fengguang
2011-08-19 2:53 ` Vivek Goyal
2011-08-19 2:53 ` Vivek Goyal
2011-08-19 3:25 ` Wu Fengguang
2011-08-19 3:25 ` Wu Fengguang
[not found] <CAFdhcLRKvfqBnXCXLwq-Qe1eNAGC-8XJ3BtHpQKzaa3RhHyp6A@mail.gmail.com>
2011-08-17 6:40 ` David Horner
2011-08-17 12:03 ` Jan Kara
2011-08-17 12:35 ` Wu Fengguang
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