From: Erik Mouw <erik@harddisk-recovery.com>
To: Linus Torvalds <torvalds@osdl.org>
Cc: Aubrey <aubreylee@gmail.com>, Hua Zhong <hzhong@gmail.com>,
Hugh Dickins <hugh@veritas.com>,
linux-kernel@vger.kernel.org, hch@infradead.org,
kenneth.w.chen@intel.com, akpm@osdl.org, mjt@tls.msk.ru
Subject: Re: O_DIRECT question
Date: Thu, 11 Jan 2007 13:45:21 +0100 [thread overview]
Message-ID: <20070111124521.GN13675@harddisk-recovery.com> (raw)
In-Reply-To: <Pine.LNX.4.64.0701101902270.3594@woody.osdl.org>
On Wed, Jan 10, 2007 at 07:05:30PM -0800, Linus Torvalds wrote:
> I should have fought back harder. There really is no valid reason for EVER
> using O_DIRECT. You need a buffer whatever IO you do, and it might as well
> be the page cache. There are better ways to control the page cache than
> play games and think that a page cache isn't necessary.
There is a valid reason: you really don't want to go through the page
cache when a hard drive has bad blocks. The only way to get fast
recovery and correct error reporting to userspace is by using O_DIRECT.
> So don't use O_DIRECT. Use things like madvise() and posix_fadvise()
> instead.
Both don't do what I want it to do: only read the sector I request you
to read and certainly do not try to outsmart me by doing some kind of
readahead.
Erik
--
+-- Erik Mouw -- www.harddisk-recovery.com -- +31 70 370 12 90 --
| Lab address: Delftechpark 26, 2628 XH, Delft, The Netherlands
next prev parent reply other threads:[~2007-01-11 12:45 UTC|newest]
Thread overview: 130+ messages / expand[flat|nested] mbox.gz Atom feed top
2007-01-11 2:57 O_DIRECT question Aubrey
2007-01-11 3:05 ` Linus Torvalds
2007-01-11 3:15 ` Linus Torvalds
2007-01-11 6:09 ` Nick Piggin
2007-01-11 15:50 ` Linus Torvalds
2007-01-11 16:19 ` Aubrey
2007-01-16 3:41 ` Jörn Engel
2007-01-11 16:23 ` bert hubert
2007-01-11 16:52 ` Xavier Bestel
2007-01-11 17:04 ` Linus Torvalds
2007-01-11 18:41 ` Trond Myklebust
2007-01-11 19:00 ` Linus Torvalds
2007-01-11 19:49 ` Trond Myklebust
2007-01-12 17:03 ` Viktor
2007-01-20 16:19 ` Denis Vlasenko
2007-01-22 15:52 ` Phillip Susi
2007-01-11 5:50 ` Aubrey
2007-01-11 6:06 ` Andrew Morton
2007-01-11 6:45 ` Aubrey
2007-01-11 6:57 ` Andrew Morton
2007-01-11 7:05 ` Nick Piggin
2007-01-11 7:54 ` Aubrey
2007-01-11 8:05 ` Roy Huang
2007-01-11 16:45 ` Linus Torvalds
2007-01-17 4:29 ` Aubrey Li
2007-01-12 2:12 ` Aubrey
2007-01-12 2:47 ` Nick Piggin
2007-01-12 3:59 ` Roy Huang
2007-01-11 8:12 ` Nick Piggin
2007-01-11 8:49 ` Roy Huang
2007-01-11 9:09 ` Nick Piggin
2007-01-12 2:48 ` Bill Davidsen
2007-01-12 4:30 ` Nick Piggin
2007-01-12 4:46 ` Linus Torvalds
2007-01-12 4:56 ` Nick Piggin
2007-01-12 4:58 ` Nick Piggin
2007-01-12 5:18 ` Linus Torvalds
2007-01-12 5:22 ` Aubrey
2007-01-12 14:59 ` Bill Davidsen
2007-01-13 4:51 ` Nick Piggin
2007-01-11 6:16 ` Alexander Shishkin
2007-01-11 6:57 ` Aubrey
2007-01-11 12:13 ` Viktor
2007-01-11 15:53 ` Phillip Susi
2007-01-11 16:20 ` Linus Torvalds
2007-01-11 17:13 ` Michael Tokarev
2007-01-11 23:01 ` Phillip Susi
2007-01-11 23:06 ` Hua Zhong
2007-01-12 15:21 ` Phillip Susi
2007-01-20 16:36 ` Denis Vlasenko
2007-01-20 20:55 ` Michael Tokarev
2007-01-20 23:05 ` Denis Vlasenko
2007-01-21 12:09 ` Michael Tokarev
2007-01-21 20:02 ` Denis Vlasenko
2007-01-22 16:17 ` Phillip Susi
2007-01-24 21:15 ` Denis Vlasenko
2007-01-25 15:44 ` Phillip Susi
2007-01-25 17:38 ` Denis Vlasenko
2007-01-25 19:28 ` Phillip Susi
2007-01-25 19:52 ` Denis Vlasenko
2007-01-25 20:03 ` Phillip Susi
2007-01-25 20:45 ` Michael Tokarev
2007-01-25 21:11 ` Denis Vlasenko
2007-01-26 16:02 ` Mark Lord
2007-01-26 16:52 ` Viktor
2007-01-26 16:58 ` Phillip Susi
2007-01-26 17:05 ` Phillip Susi
2007-01-26 23:16 ` Denis Vlasenko
2007-02-06 20:39 ` Pavel Machek
2007-01-26 18:23 ` Bill Davidsen
2007-01-26 23:35 ` Denis Vlasenko
2007-01-28 15:18 ` Bill Davidsen
2007-01-28 17:03 ` Denis Vlasenko
2007-01-29 15:43 ` Phillip Susi
2007-01-29 17:00 ` Andrea Arcangeli
2007-01-30 0:05 ` Denis Vlasenko
[not found] ` <45BE7D99.70200@cfl.rr.com>
[not found] ` <20070130023056.GN8030@opteron.random>
[not found] ` <45BF65E3.6070102@cfl.rr.com>
[not found] ` <20070130164806.GQ8030@opteron.random>
2007-01-30 18:50 ` Phillip Susi
2007-01-30 19:57 ` Andrea Arcangeli
2007-01-30 20:06 ` Andrea Arcangeli
2007-01-30 23:07 ` Phillip Susi
2007-01-31 2:28 ` Andrea Arcangeli
2007-01-31 9:37 ` Michael Tokarev
2007-01-26 15:53 ` Bill Davidsen
2007-01-11 17:42 ` Alan
2007-01-11 18:00 ` Linus Torvalds
2007-01-12 7:57 ` dean gaudet
2007-01-12 15:27 ` Phillip Susi
2007-01-12 18:06 ` Linus Torvalds
2007-01-12 20:23 ` Chris Mason
2007-01-12 20:46 ` Michael Tokarev
2007-01-12 20:52 ` Michael Tokarev
2007-01-12 21:03 ` Michael Tokarev
2007-01-12 21:17 ` Linus Torvalds
2007-01-12 21:54 ` Michael Tokarev
2007-01-12 22:09 ` Linus Torvalds
2007-01-12 22:26 ` Michael Tokarev
2007-01-12 22:35 ` Erik Andersen
2007-01-12 22:47 ` Andrew Morton
2007-01-14 9:11 ` Nate Diller
2007-01-20 16:45 ` Denis Vlasenko
2007-01-22 1:47 ` Andrea Arcangeli
2007-01-13 20:07 ` Bill Davidsen
2007-01-13 20:27 ` Michael Tokarev
2007-01-14 15:39 ` Bill Davidsen
2007-01-12 21:39 ` Disk Cache, Was: " Zan Lynx
2007-01-12 22:10 ` Michael Tokarev
2007-01-15 12:11 ` Helge Hafting
2007-01-12 16:59 ` Viktor
2007-01-11 12:45 ` Erik Mouw [this message]
2007-01-11 4:51 ` Andrew Morton
2007-01-11 5:06 ` Gerrit Huizenga
2007-01-11 16:09 ` Badari Pulavarty
2007-01-11 12:34 ` linux-os (Dick Johnson)
2007-01-11 13:06 ` Martin Mares
2007-01-11 14:15 ` Jens Axboe
2007-01-12 2:13 ` Bill Davidsen
-- strict thread matches above, loose matches on Subject: below --
2007-01-17 14:27 Alex Tomas
2007-01-22 15:59 Al Boldi
[not found] <7BYkO-5OV-17@gated-at.bofh.it>
[not found] ` <7BYul-6gz-5@gated-at.bofh.it>
[not found] ` <7C18X-1zo-5@gated-at.bofh.it>
[not found] ` <7C1iw-22q-7@gated-at.bofh.it>
[not found] ` <7C1Vb-2Ny-3@gated-at.bofh.it>
[not found] ` <7C256-2ZR-27@gated-at.bofh.it>
[not found] ` <7C2eE-3rT-15@gated-at.bofh.it>
[not found] ` <7C31d-4qb-11@gated-at.bofh.it>
[not found] ` <7C3kj-55E-9@gated-at.bofh.it>
2007-01-11 13:20 ` Bodo Eggert
[not found] ` <7C74B-2A4-23@gated-at.bofh.it>
[not found] ` <7CaYA-mT-19@gated-at.bofh.it>
[not found] ` <7Cpuz-64X-1@gated-at.bofh.it>
[not found] ` <7Cz0T-4PH-17@gated-at.bofh.it>
[not found] ` <7CBcl-86B-9@gated-at.bofh.it>
[not found] ` <7CBvH-52-9@gated-at.bofh.it>
[not found] ` <7CBFn-hw-1@gated-at.bofh.it>
[not found] ` <7CBP1-KI-3@gated-at.bofh.it>
[not found] ` <7CBYG-WK-3@gated-at.bofh.it>
2007-01-13 16:53 ` Bodo Eggert
2007-01-13 19:30 ` Bill Davidsen
2007-01-14 18:51 ` Bodo Eggert
[not found] ` <7CXmz-88G-29@gated-at.bofh.it>
[not found] ` <7CXFR-8vZ-15@gated-at.bofh.it>
[not found] ` <7DfMP-2ak-19@gated-at.bofh.it>
2007-01-14 19:39 ` Bodo Eggert
[not found] ` <7DyYK-6lE-3@gated-at.bofh.it>
2007-01-16 20:26 ` Bodo Eggert
2007-01-17 5:55 ` Arjan van de Ven
2007-01-17 22:36 ` Bodo Eggert
[not found] ` <7HkaQ-2Nb-9@gated-at.bofh.it>
[not found] ` <7HDZP-Pv-1@gated-at.bofh.it>
[not found] ` <7HIPV-8kp-35@gated-at.bofh.it>
2007-01-27 14:01 ` Bodo Eggert
2007-01-27 14:14 ` Denis Vlasenko
2007-01-28 15:30 ` Bill Davidsen
2007-01-28 17:18 ` Denis Vlasenko
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