From: Peter Lieven <pl@kamp.de>
To: Kevin Wolf <kwolf@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>
Cc: ronniesahlberg@gmail.com, qemu-devel@nongnu.org, stefanha@redhat.com
Subject: Re: [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk}
Date: Fri, 11 Oct 2013 09:35:46 +0200 [thread overview]
Message-ID: <5257AA52.5040307@kamp.de> (raw)
In-Reply-To: <20131008123908.GG25109@dhcp-200-207.str.redhat.com>
On 08.10.2013 14:39, Kevin Wolf wrote:
> Am 08.10.2013 um 14:35 hat Paolo Bonzini geschrieben:
>> Il 08/10/2013 14:33, Kevin Wolf ha scritto:
>>>>>>> this converts read, write and flush functions from aio to coroutines.
>>>>> I'm not sure it's already the time for this... Cancellation sucks in
>>>>> QEMU, and this is going to make things even worse.
>>> Not sure what you're referring to. If you mean iscsi_aio_cancel(), isn't
>>> it dead code anyway since we changed block.c to use coroutines for
>>> everything? bdrv_co_io_em() even throws the acb away, so even if you
>>> wanted, there's no way to cancel the request even today.
>> SCSI tries to use cancellation, and this results in VCPU threads
>> starving all other threads. So I would like to introduce cancellation
>> points for coroutines.
> Sounds like a nice thing to have, but it's unrelated to this patch.
> Cancellation means waiting for request completion before and after the
> patch.
Is there anything I can contribute or is this all outside the iscsi driver?
next prev parent reply other threads:[~2013-10-11 7:36 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-10-02 15:41 [Qemu-devel] [PATCH] block/iscsi: introduce bdrv_co_{readv, writev, flush_to_disk} Peter Lieven
2013-10-02 15:46 ` Paolo Bonzini
2013-10-02 15:54 ` Peter Lieven
2013-10-02 15:55 ` Paolo Bonzini
2013-10-02 15:57 ` Peter Lieven
2013-10-08 12:33 ` Kevin Wolf
2013-10-08 12:35 ` Paolo Bonzini
2013-10-08 12:39 ` Kevin Wolf
2013-10-11 7:35 ` Peter Lieven [this message]
2013-11-25 10:47 ` Peter Lieven
2013-11-25 10:54 ` Paolo Bonzini
2013-11-25 10:56 ` Peter Lieven
2013-11-25 10:57 ` Paolo Bonzini
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=5257AA52.5040307@kamp.de \
--to=pl@kamp.de \
--cc=kwolf@redhat.com \
--cc=pbonzini@redhat.com \
--cc=qemu-devel@nongnu.org \
--cc=ronniesahlberg@gmail.com \
--cc=stefanha@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 a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox;
as well as URLs for NNTP newsgroup(s).