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From: Mikulas Patocka <mpatocka@redhat.com>
To: device-mapper development <dm-devel@redhat.com>
Cc: linux-kernel@vger.kernel.org, Frank Mayhar <fmayhar@google.com>
Subject: Re: [dm-devel] dm: Make MIN_IOS, et al, tunable via sysctl.
Date: Tue, 20 Aug 2013 17:44:39 -0400 (EDT)	[thread overview]
Message-ID: <alpine.LRH.2.02.1308201742350.8826@file01.intranet.prod.int.rdu2.redhat.com> (raw)
In-Reply-To: <1376934845.24869.43.camel@bobble.lax.corp.google.com>



On Mon, 19 Aug 2013, Frank Mayhar wrote:

> On Mon, 2013-08-19 at 10:00 -0400, Mike Snitzer wrote:
> > Performance isn't the concern.  The concern is: does DM allow for
> > forward progress if the system's memory is completely exhausted?
> > 
> > This is why request-based has such an extensive reserve, because it
> > needs to account for cloning the largest possible request that comes in
> > (with multiple bios).
> 
> Thanks for the response.  In our particular case, I/O will be file
> system based and over a network, which makes it pretty easy for us to be
> sure that large I/Os never happen.  That notwithstanding, however, as
> you said it just seems reasonable to make these values configurable.
> 
> I'm also looking at making some similar constants in dm-verity and
> dm-bufio configurable in the same way and for similar reasons.

Regarding dm-bufio: the user of dm-bufio sets the pool size as an argument 
in dm_bufio_client_create. There is no need to make it configurable - if 
the user selects too low value, deadlock is possible, if the user selects 
too high value, there is no additional advantage.

Regarding dm-verity: the mempool size is 4, there is no need to make it 
bigger, there is no advantage from that.

Mikulas

  parent reply	other threads:[~2013-08-20 21:44 UTC|newest]

Thread overview: 61+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2013-08-09 17:48 [PATCH] dm: Make MIN_IOS, et al, tunable via sysctl Frank Mayhar
2013-08-13 16:41 ` Frank Mayhar
2013-08-16 22:58 ` Frank Mayhar
2013-08-17 12:30 ` [dm-devel] " Alasdair G Kergon
2013-08-19 13:40   ` Mike Snitzer
2013-08-19 15:04     ` Frank Mayhar
2013-08-19 14:00 ` Mike Snitzer
2013-08-19 14:00   ` Mike Snitzer
2013-08-19 17:54   ` [dm-devel] " Frank Mayhar
2013-08-19 18:15     ` Mike Snitzer
2013-08-20 21:44     ` Mikulas Patocka [this message]
2013-08-20 21:52       ` [dm-devel] " Frank Mayhar
2013-08-20 21:41   ` Mikulas Patocka
2013-08-20 21:22 ` [dm-devel] [PATCH] " Mikulas Patocka
2013-08-20 21:28   ` Frank Mayhar
2013-08-20 21:47     ` Mikulas Patocka
2013-08-20 21:57       ` Frank Mayhar
2013-08-20 22:24         ` Mike Snitzer
2013-08-20 22:52           ` Mikulas Patocka
2013-08-20 23:14           ` Frank Mayhar
2013-08-22 17:26             ` Frank Mayhar
2013-08-26 14:28             ` Mikulas Patocka
2013-09-12 22:24               ` [PATCH 0/7] dm: allow mempool and bioset reserves to be tuned Mike Snitzer
2013-09-12 22:24                 ` [PATCH 1/7] dm: lower bio-based mempool reservation Mike Snitzer
2013-09-12 22:40                   ` Mikulas Patocka
2013-09-12 22:24                 ` [PATCH 2/7] dm: add reserved_rq_based_ios module parameter Mike Snitzer
2013-09-12 22:45                   ` Mikulas Patocka
2013-09-12 23:15                     ` Mike Snitzer
2013-09-12 23:27                       ` Mikulas Patocka
2013-09-12 23:32                         ` Mike Snitzer
2013-09-12 22:24                 ` [PATCH 3/7] dm: add reserved_bio_based_ios " Mike Snitzer
2013-09-12 22:47                   ` Mikulas Patocka
2013-09-12 23:11                     ` Mike Snitzer
2013-09-12 23:17                       ` Mikulas Patocka
2013-09-18 15:17                         ` Frank Mayhar
2013-09-12 22:24                 ` [PATCH 4/7] dm io: use dm_get_reserved_bio_based_ios to size reserves Mike Snitzer
2013-09-12 22:48                   ` Mikulas Patocka
2013-09-12 22:24                 ` [PATCH 5/7] dm mpath: use dm_get_reserved_rq_based_ios to size mempool Mike Snitzer
2013-09-12 22:48                   ` Mikulas Patocka
2013-09-12 22:24                 ` [PATCH 6/7] dm: track the maximum number of bios in a cloned request Mike Snitzer
2013-09-12 22:55                   ` Mikulas Patocka
2013-09-12 23:09                     ` Mike Snitzer
2013-09-12 22:24                 ` [PATCH 7/7] dm: optimize clone_rq() when track_peak_rq_based_ios is disabled Mike Snitzer
2013-09-12 23:00                   ` Mikulas Patocka
2013-09-12 23:06                     ` Mike Snitzer
2013-09-12 23:30                       ` Mikulas Patocka
2013-09-12 23:53                         ` Mike Snitzer
2013-09-13  4:46                           ` Jun'ichi Nomura
2013-09-13 13:04                             ` Mike Snitzer
2013-09-13 14:34                             ` Mikulas Patocka
2013-09-13 18:59                 ` [PATCH v2 0/3] dm: allow mempool and bioset reserves to be tuned Mike Snitzer
2013-09-13 18:59                   ` [PATCH v2 1/3] dm: lower bio-based mempool reservation Mike Snitzer
2013-09-13 18:59                   ` [PATCH v2 2/3] dm: add reserved_rq_based_ios module parameter Mike Snitzer
2013-09-13 18:59                   ` [PATCH v2 3/3] dm: add reserved_bio_based_ios " Mike Snitzer
2013-09-13 19:22                   ` [PATCH v2 0/3] dm: allow mempool and bioset reserves to be tuned Mike Snitzer
2013-09-13 20:30                     ` Mike Snitzer
2013-09-13 21:08                       ` [PATCH v3 " Mike Snitzer
2013-09-13 21:08                         ` [PATCH v3 1/3] dm: lower bio-based mempool reservation Mike Snitzer
2013-09-13 21:08                         ` [PATCH v3 2/3] dm: add reserved_rq_based_ios module parameter Mike Snitzer
2013-09-13 21:08                         ` [PATCH v3 3/3] dm: add reserved_bio_based_ios " Mike Snitzer
2013-09-18 15:10                         ` [PATCH v3 0/3] dm: allow mempool and bioset reserves to be tuned Frank Mayhar

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