From: Jeff Dike <jdike@karaya.com>
To: Ryan Cumming <bodnar42@phalynx.dhs.org>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Special Kernel Modification
Date: Mon, 05 Nov 2001 00:52:51 -0500 [thread overview]
Message-ID: <200111050552.AAA06451@ccure.karaya.com> (raw)
In-Reply-To: Your message of "Sun, 04 Nov 2001 19:13:15 PST." <E160aCK-0001Fs-00@localhost>
bodnar42@phalynx.dhs.org said:
> > Mounting it synchronous will disable caching in the VM.
> Who told
> you that? Synchronous mounting turns off write buffering. Even with
> "-o sync" writes will still end up in the page cache, they'll just be
> commited immediately.
Ummm, how about O_DIRECT instead of O_SYNC (or maybe as well, my googling
hasn't been clear on whether O_DIRECT bypasses the cache on writes as well)?
All IO bypasses the virtual machine cache, so there's no multiple caching.
> Er, it will be shared in the host's context, but each VM will still
> have their own copy in the page cache. This is no better than a
> COW'ed block device
Nope. You O_DIRECT here as well.
Jeff
next prev parent reply other threads:[~2001-11-05 4:34 UTC|newest]
Thread overview: 23+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-11-05 0:01 Special Kernel Modification Lonnie Cumberland
2001-11-05 0:19 ` Ryan Cumming
2001-11-05 0:29 ` lonnie
2001-11-05 1:04 ` Jan-Benedict Glaw
2001-11-05 3:04 ` Mike Fedyk
2001-11-06 0:34 ` Jorgen Cederlof
2001-11-06 0:38 ` lonnie
2001-11-05 0:22 ` Alan Cox
2001-11-05 0:39 ` Phil Sorber
2001-11-05 0:38 ` Rik van Riel
2001-11-05 1:04 ` Jeremy Jackson
2001-11-05 1:58 ` Jeff Dike
2001-11-05 2:14 ` Ryan Cumming
2001-11-05 4:02 ` Jeff Dike
2001-11-05 3:13 ` Ryan Cumming
2001-11-05 5:52 ` Jeff Dike [this message]
2001-11-05 5:30 ` Ryan Cumming
2001-11-05 14:22 ` Jeff Dike
2001-11-05 16:53 ` Andrea Arcangeli
2001-11-05 20:18 ` Jeff Dike
2001-11-05 19:05 ` Andrea Arcangeli
-- strict thread matches above, loose matches on Subject: below --
2001-11-05 0:37 John Weber
[not found] <E160aCK-0001Fs-00@localhost.suse.lists.linux.kernel>
[not found] ` <200111050552.AAA06451@ccure.karaya.com.suse.lists.linux.kernel>
2001-11-05 6:22 ` Andi Kleen
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