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From: Wu Fengguang <fengguang.wu@intel.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: Jan Kara <jack@suse.cz>,
	"linux-fsdevel@vger.kernel.org" <linux-fsdevel@vger.kernel.org>,
	"hch@infradead.org" <hch@infradead.org>,
	"jaxboe@fusionio.com" <jaxboe@fusionio.com>
Subject: Re: [PATCH 1/3 v2] mm: Stop background writeback if there is other work queued for the thread
Date: Sun, 8 Aug 2010 00:04:00 +0800	[thread overview]
Message-ID: <20100807160400.GA6027@localhost> (raw)
In-Reply-To: <20100805164535.f28d8807.akpm@linux-foundation.org>

On Fri, Aug 06, 2010 at 07:45:35AM +0800, Andrew Morton wrote:
> On Thu,  5 Aug 2010 20:53:17 +0200
> Jan Kara <jack@suse.cz> wrote:
> 
> > Background writeback and kupdate-style writeback
> 
> What the heck's the difference between "Background writeback" and
> "kupdate-style" writeback?  afacit "background" means "not due to
> kupdate, but due to a vmscan poke or something like that".  But the
> terms aren't defined anywhere and the wb_writeback_work fields are
> uncommented and the functions are undocumented and no wonder we keep
> making such a mess of this code.

I happen to describe these terms in another email :)

...there are always four main writeback goals/semantics:
- periodic      stop when all 30s-old inodes are written
- background    stop when background threshold is reached
- nr_pages      stop when nr_pages written (or when all clean)
- sync          stop when all older-than-sync-time inodes/pages are written

Thanks,
Fengguang

  reply	other threads:[~2010-08-07 16:21 UTC|newest]

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2010-08-05 18:53 [PATCH 0/3 v2] Three writeback fixes to stop sync(1) livelocks Jan Kara
2010-08-05 18:53 ` [PATCH 1/3 v2] mm: Stop background writeback if there is other work queued for the thread Jan Kara
2010-08-05 19:38   ` Jens Axboe
2010-08-05 23:45   ` Andrew Morton
2010-08-07 16:04     ` Wu Fengguang [this message]
2010-08-08  2:43     ` Jan Kara
2010-08-08  3:10       ` Wu Fengguang
2010-08-08  4:12     ` Dave Chinner
2010-08-08  7:29       ` Wu Fengguang
2010-08-08 11:07         ` Jens Axboe
2010-08-08 13:59           ` Jan Kara
2010-08-08 22:55             ` Wu Fengguang
2010-08-05 18:53 ` [PATCH 2/3 v2] mm: Fix writeback_in_progress() Jan Kara
2010-08-05 19:37   ` Jens Axboe
2010-08-05 23:06   ` Wu Fengguang
2010-08-06  0:10   ` Andrew Morton
2010-08-08  2:25     ` Jan Kara
2010-08-05 18:53 ` [PATCH 3/3 v2] mm: Avoid resetting wb_start after each writeback round Jan Kara
2010-08-05 19:38   ` Jens Axboe
2010-08-06  0:21   ` Andrew Morton
2010-08-07 22:45     ` Jan Kara
2010-08-06 12:23 ` [PATCH 0/3 v2] Three writeback fixes to stop sync(1) livelocks Christoph Hellwig

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