All of lore.kernel.org
 help / color / mirror / Atom feed
From: Frank Mayhar <fmayhar@google.com>
To: Mike Snitzer <snitzer@redhat.com>
Cc: Mikulas Patocka <mpatocka@redhat.com>,
	device-mapper development <dm-devel@redhat.com>,
	linux-kernel@vger.kernel.org
Subject: Re: dm: Make MIN_IOS, et al, tunable via sysctl.
Date: Tue, 20 Aug 2013 16:14:22 -0700	[thread overview]
Message-ID: <1377040462.24869.70.camel@bobble.lax.corp.google.com> (raw)
In-Reply-To: <20130820222439.GA5883@redhat.com>

On Tue, 2013-08-20 at 18:24 -0400, Mike Snitzer wrote:
> Mikulas' point is that you cannot reduce the size to smaller than 1.
> And aside from rq-based DM, 1 is sufficient to allow for forward
> progress even when memory is completely consumed.
> 
> A patch that simply changes them to 1 but makes the rq-based DM
> mempool's size configurable should actually be fine.

So you're saying that I should submit a patch to drop the pool size for
BIO_BASED to 1 and make the pool size for REQUEST_BASED configurable?
At the moment, in dm.c the former is hardcoded to 16 and the latter is
set via MIN_IOS (currently 256).  There's also io_pool, a slab pool,
which is also set via MIN_IOS.

How does this relate to the rest of the DM modules?  Mpath also sets
MIN_IOS to 256 and creates a slab pool from that, and there are a number
of hardcoded constants in dm-io (MIN_IOS and MIN_BIOS), dm-snap
(MIN_IOS), dm-crypt (MIN_IOS and MIN_POOL_PAGES), dm-bufio
(DM_BUFIO_HASH_BITS, which is allocated via vmalloc per client) and
dm-verity (DM_VERITY_MEMPOOL_SIZE, which is allocated per device).

For the most part I can't imagine that people will want to change these
from their defaults, but when someone does need to change one of these,
they need to do so badly and there's currently no good way to do that
besides hacking the source and building a new kernel.

By the way, I do appreciate the advice.  I'm just trying to clear up
confusion on my part, make sure that our needs are met and, while I'm at
it, make things a bit better for those who come after me.
-- 
Frank Mayhar
310-460-4042


  parent reply	other threads:[~2013-08-20 23:14 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     ` [dm-devel] " Mikulas Patocka
2013-08-20 21:52       ` 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 [this message]
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

Reply instructions:

You may reply publicly to this message via plain-text email
using any one of the following methods:

* Save the following mbox file, import it into your mail client,
  and reply-to-all from there: mbox

  Avoid top-posting and favor interleaved quoting:
  https://en.wikipedia.org/wiki/Posting_style#Interleaved_style

* Reply using the --to, --cc, and --in-reply-to
  switches of git-send-email(1):

  git send-email \
    --in-reply-to=1377040462.24869.70.camel@bobble.lax.corp.google.com \
    --to=fmayhar@google.com \
    --cc=dm-devel@redhat.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=mpatocka@redhat.com \
    --cc=snitzer@redhat.com \
    /path/to/YOUR_REPLY

  https://kernel.org/pub/software/scm/git/docs/git-send-email.html

* If your mail client supports setting the In-Reply-To header
  via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line before the message body. 
This is an external index of several public inboxes,
see mirroring instructions on how to clone and mirror
all data and code used by this external index.