From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: kvm-devel <kvm-devel@lists.sourceforge.net>,
Jamie Lokier <jamie@shareable.org>
Subject: Re: [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request
Date: Sat, 29 Mar 2008 02:02:53 +0000 [thread overview]
Message-ID: <200803290202.54431.paul@codesourcery.com> (raw)
In-Reply-To: <20080329011751.GB30219@shareable.org>
> That'll depend on what kind of device is emulated. Does the SCSI
> emulation handle multiple in-flight commands with any guarantee on
> order?
SCSI definitely allows (and we emulate) multiple in flight commands.
I can't find any requirement that writes must complete before a subsequent
SYNCHRONISE_CACHE. However I don't claim to know the spec that well, and it's
probably not a bad idea have them complete anyway. Preferably this would be a
completely asynchronous operation. i.e. the sync command returns immediately,
but only completes when all preceding writes have completed and been flushed
to disk.
Paul
-------------------------------------------------------------------------
Check out the new SourceForge.net Marketplace.
It's the best place to buy or sell services for
just about anything Open Source.
http://ad.doubleclick.net/clk;164216239;13503038;w?http://sf.net/marketplace
WARNING: multiple messages have this Message-ID (diff)
From: Paul Brook <paul@codesourcery.com>
To: qemu-devel@nongnu.org
Cc: kvm-devel <kvm-devel@lists.sourceforge.net>
Subject: Re: [kvm-devel] [Qemu-devel] [PATCH] QEMU: fsync AIO writes on flush request
Date: Sat, 29 Mar 2008 02:02:53 +0000 [thread overview]
Message-ID: <200803290202.54431.paul@codesourcery.com> (raw)
In-Reply-To: <20080329011751.GB30219@shareable.org>
> That'll depend on what kind of device is emulated. Does the SCSI
> emulation handle multiple in-flight commands with any guarantee on
> order?
SCSI definitely allows (and we emulate) multiple in flight commands.
I can't find any requirement that writes must complete before a subsequent
SYNCHRONISE_CACHE. However I don't claim to know the spec that well, and it's
probably not a bad idea have them complete anyway. Preferably this would be a
completely asynchronous operation. i.e. the sync command returns immediately,
but only completes when all preceding writes have completed and been flushed
to disk.
Paul
next prev parent reply other threads:[~2008-03-29 2:02 UTC|newest]
Thread overview: 33+ messages / expand[flat|nested] mbox.gz Atom feed top
2008-03-28 15:05 [PATCH] QEMU: fsync AIO writes on flush request Marcelo Tosatti
2008-03-28 15:05 ` [Qemu-devel] " Marcelo Tosatti
2008-03-28 15:07 ` Jamie Lokier
2008-03-28 15:07 ` Jamie Lokier
2008-03-28 16:31 ` Marcelo Tosatti
2008-03-28 16:31 ` [kvm-devel] " Marcelo Tosatti
2008-03-28 16:40 ` Paul Brook
2008-03-28 16:40 ` [kvm-devel] " Paul Brook
2008-03-28 16:59 ` Marcelo Tosatti
2008-03-28 16:59 ` [kvm-devel] " Marcelo Tosatti
2008-03-28 17:00 ` Paul Brook
2008-03-28 17:00 ` [kvm-devel] " Paul Brook
2008-03-28 18:13 ` Marcelo Tosatti
2008-03-28 18:13 ` [kvm-devel] " Marcelo Tosatti
2008-03-29 1:17 ` Jamie Lokier
2008-03-29 1:17 ` [kvm-devel] " Jamie Lokier
2008-03-29 2:02 ` Paul Brook [this message]
2008-03-29 2:02 ` Paul Brook
2008-03-29 2:11 ` Jamie Lokier
2008-03-29 2:11 ` [kvm-devel] " Jamie Lokier
2008-03-29 2:43 ` Paul Brook
2008-03-29 2:43 ` [kvm-devel] " Paul Brook
2008-03-28 18:03 ` Jamie Lokier
2008-03-28 18:03 ` [kvm-devel] " Jamie Lokier
2008-03-28 18:36 ` Marcelo Tosatti
2008-03-28 18:36 ` [kvm-devel] " Marcelo Tosatti
2008-03-29 1:09 ` Jamie Lokier
2008-03-29 1:09 ` [kvm-devel] " Jamie Lokier
2008-03-29 6:49 ` Marcelo Tosatti
2008-03-29 6:49 ` [kvm-devel] " Marcelo Tosatti
2008-03-28 17:25 ` Ian Jackson
2008-03-28 17:25 ` Ian Jackson
2008-03-28 19:11 ` [kvm-devel] " Marcelo Tosatti
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=200803290202.54431.paul@codesourcery.com \
--to=paul@codesourcery.com \
--cc=jamie@shareable.org \
--cc=kvm-devel@lists.sourceforge.net \
--cc=qemu-devel@nongnu.org \
/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.