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From: Trond Myklebust <trond.myklebust@fys.uio.no>
To: Andrew Morton <akpm@osdl.org>
Cc: Neil Brown <neilb@suse.de>, David Chinner <dgc@sgi.com>,
	linux-kernel@vger.kernel.org
Subject: Re: RFC - how to balance Dirty+Writeback in the face of slow writeback.
Date: Thu, 17 Aug 2006 08:36:19 -0400	[thread overview]
Message-ID: <1155818179.5662.19.camel@localhost> (raw)
In-Reply-To: <20060816231448.cc71fde7.akpm@osdl.org>

On Wed, 2006-08-16 at 23:14 -0700, Andrew Morton wrote:
> btw, one thing which afaik NFS _still_ doesn't do is to wake up processes
> which are stuck in blk_congestion_wait() when NFS has retired a bunch of
> writes.  It should do so, otherwise NFS write-intensive workloads might end
> up sleeping for too long.  I guess the amount of buffering and hysteresis
> we have in there has thus far prevented any problems from being observed.

Are we to understand it that you consider blk_congestion_wait() to be an
official API, and not just another block layer hack inside the VM?

'cos currently the only tools for waking up processes in
blk_congestion_wait() are the two routines:

   static void clear_queue_congested(request_queue_t *q, int rw)
and
   static void set_queue_congested(request_queue_t *q, int rw)

in block/ll_rw_blk.c. Hardly a model of well thought out code...

  Trond


  reply	other threads:[~2006-08-17 12:37 UTC|newest]

Thread overview: 37+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2006-08-14 23:40 RFC - how to balance Dirty+Writeback in the face of slow writeback Neil Brown
2006-08-15  8:06 ` Andrew Morton
2006-08-15 23:00   ` David Chinner
2006-08-17  4:08     ` Neil Brown
2006-08-17  6:14       ` Andrew Morton
2006-08-17 12:36         ` Trond Myklebust [this message]
2006-08-17 15:14           ` Andrew Morton
2006-08-17 16:22             ` Trond Myklebust
2006-08-18  5:49               ` Andrew Morton
2006-08-18 10:43                 ` Nikita Danilov
2006-08-18  0:11         ` David Chinner
2006-08-18  6:29           ` Andrew Morton
2006-08-18  7:03             ` Jens Axboe
2006-08-18  7:11               ` Andrew Morton
2006-08-18 18:57               ` Andi Kleen
2006-08-21  0:35                 ` Neil Brown
2006-08-21  3:15                   ` David Chinner
2006-08-21  7:24                     ` Neil Brown
2006-08-21 13:51                       ` Jens Axboe
2006-08-25  4:36                         ` Neil Brown
2006-08-25  6:37                           ` Jens Axboe
2006-08-28  1:28                             ` David Chinner
2006-08-25 13:16                           ` Trond Myklebust
2006-08-27  8:21                             ` Neil Brown
2006-08-21 14:28                       ` David Chinner
2006-08-25  5:24                         ` Neil Brown
2006-08-28  1:55                           ` David Chinner
2006-08-21  7:47                     ` Andi Kleen
2006-08-18  7:07             ` Neil Brown
2006-08-17 22:17       ` David Chinner
2006-08-17  3:59   ` Neil Brown
2006-08-17  6:22     ` Andrew Morton
2006-08-17  8:36       ` Jens Axboe
2006-08-17 13:21     ` Trond Myklebust
2006-08-17 15:30       ` Andrew Morton
2006-08-17 16:18         ` Trond Myklebust
2006-08-18  5:34           ` Andrew Morton

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