From: Evgeniy Polyakov <johnpol@2ka.mipt.ru>
To: Daniel Phillips <phillips@phunq.net>
Cc: Jens Axboe <jens.axboe@oracle.com>,
netdev@vger.kernel.org, linux-kernel@vger.kernel.org,
linux-fsdevel@vger.kernel.org,
Peter Zijlstra <peterz@infradead.org>
Subject: Re: Block device throttling [Re: Distributed storage.]
Date: Tue, 14 Aug 2007 12:46:25 +0400 [thread overview]
Message-ID: <20070814084625.GA20265@2ka.mipt.ru> (raw)
In-Reply-To: <200708130604.07154.phillips@phunq.net>
On Mon, Aug 13, 2007 at 06:04:06AM -0700, Daniel Phillips (phillips@phunq.net) wrote:
> Perhaps you never worried about the resources that the device mapper
> mapping function allocates to handle each bio and so did not consider
> this hole significant. These resources can be significant, as is the
> case with ddsnap. It is essential to close that window through with
> the virtual device's queue limit may be violated. Not doing so will
> allow deadlock.
This is not a bug, this is special kind of calculation - total limit is
number of physical devices multiplied by theirs limits. It was done
_on purpose_ to allow different device to have different limits (for
example in distributed storage project it is possible to have both remote
and local node in the same device, but local device should not have _any_
limit at all, but network one should).
Virtual device essentially has _no_ limit. And that as done on purpose.
--
Evgeniy Polyakov
next prev parent reply other threads:[~2007-08-14 8:47 UTC|newest]
Thread overview: 80+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-07-31 17:13 Distributed storage Evgeniy Polyakov
2007-08-02 21:08 ` Daniel Phillips
2007-08-03 10:26 ` Evgeniy Polyakov
2007-08-03 10:57 ` Evgeniy Polyakov
2007-08-03 12:27 ` Peter Zijlstra
2007-08-03 13:49 ` Evgeniy Polyakov
2007-08-03 14:53 ` Peter Zijlstra
2007-08-03 19:48 ` Daniel Phillips
2007-08-03 19:41 ` Daniel Phillips
2007-08-04 1:19 ` Daniel Phillips
2007-08-04 16:37 ` Evgeniy Polyakov
2007-08-05 8:04 ` Daniel Phillips
2007-08-05 15:08 ` Evgeniy Polyakov
2007-08-05 21:23 ` Daniel Phillips
2007-08-06 8:25 ` Evgeniy Polyakov
2007-08-07 12:05 ` Jens Axboe
2007-08-07 18:24 ` Daniel Phillips
2007-08-07 20:55 ` Jens Axboe
2007-08-08 9:54 ` Block device throttling [Re: Distributed storage.] Evgeniy Polyakov
2007-08-08 10:17 ` [1/1] " Evgeniy Polyakov
2007-08-08 13:28 ` Evgeniy Polyakov
2007-08-12 23:16 ` Daniel Phillips
2007-08-13 8:18 ` Evgeniy Polyakov
2007-08-27 21:57 ` Daniel Phillips
2007-08-13 5:22 ` Daniel Phillips
2007-08-13 5:36 ` Daniel Phillips
2007-08-13 6:44 ` Daniel Phillips
2007-08-13 8:14 ` Evgeniy Polyakov
2007-08-13 11:04 ` Daniel Phillips
2007-08-13 12:04 ` Evgeniy Polyakov
2007-08-13 12:18 ` Daniel Phillips
2007-08-13 12:24 ` Evgeniy Polyakov
2007-08-13 8:23 ` Evgeniy Polyakov
2007-08-13 11:18 ` Daniel Phillips
2007-08-13 12:18 ` Evgeniy Polyakov
2007-08-13 13:04 ` Daniel Phillips
2007-08-14 8:46 ` Evgeniy Polyakov [this message]
2007-08-14 11:13 ` Daniel Phillips
2007-08-14 11:30 ` Evgeniy Polyakov
2007-08-14 11:35 ` Daniel Phillips
2007-08-14 11:50 ` Evgeniy Polyakov
2007-08-14 12:32 ` Daniel Phillips
2007-08-14 12:46 ` Evgeniy Polyakov
2007-08-14 12:54 ` Daniel Phillips
2007-08-12 23:36 ` Distributed storage Daniel Phillips
2007-08-13 7:28 ` Jens Axboe
2007-08-13 7:45 ` Jens Axboe
2007-08-13 9:08 ` Daniel Phillips
2007-08-13 9:13 ` Jens Axboe
2007-08-13 9:55 ` Daniel Phillips
2007-08-13 10:06 ` Jens Axboe
2007-08-13 10:15 ` Daniel Phillips
2007-08-13 10:22 ` Jens Axboe
2007-08-13 10:32 ` Daniel Phillips
2007-08-13 9:18 ` Evgeniy Polyakov
2007-08-13 10:12 ` Daniel Phillips
2007-08-13 11:03 ` Evgeniy Polyakov
2007-08-13 11:45 ` Daniel Phillips
2007-08-13 8:59 ` Daniel Phillips
2007-08-13 9:12 ` Jens Axboe
2007-08-13 23:27 ` Daniel Phillips
2007-08-03 4:09 ` Mike Snitzer
2007-08-03 10:42 ` Evgeniy Polyakov
2007-08-04 0:49 ` Daniel Phillips
2007-08-03 5:04 ` Manu Abraham
2007-08-03 10:44 ` Evgeniy Polyakov
2007-08-04 2:51 ` Dave Dillow
2007-08-04 3:44 ` Manu Abraham
2007-08-04 17:03 ` Evgeniy Polyakov
2007-08-04 0:41 ` Daniel Phillips
2007-08-04 16:44 ` Evgeniy Polyakov
2007-08-05 8:06 ` Daniel Phillips
2007-08-05 15:01 ` Evgeniy Polyakov
2007-08-05 21:35 ` Daniel Phillips
2007-08-06 8:28 ` Evgeniy Polyakov
[not found] ` <200708281027.59528.phillips@phunq.net>
[not found] ` <20070828175403.GA28440@2ka.mipt.ru>
[not found] ` <200708281408.06618.phillips@phunq.net>
2007-08-29 8:53 ` [1/1] Block device throttling [Re: Distributed storage.] Evgeniy Polyakov
2007-08-30 23:20 ` Daniel Phillips
2007-08-31 17:33 ` Evgeniy Polyakov
2007-08-31 21:41 ` Alasdair G Kergon
2007-09-02 4:42 ` Daniel Phillips
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