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From: Paolo Bonzini <pbonzini@redhat.com>
To: Cornelia Huck <cornelia.huck@de.ibm.com>, Fam Zheng <famz@redhat.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
	qemu-block@nongnu.org, tu bo <tubo@linux.vnet.ibm.com>,
	"Michael S. Tsirkin" <mst@redhat.com>,
	qemu-devel@nongnu.org,
	Christian Borntraeger <borntraeger@de.ibm.com>,
	Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop
Date: Tue, 22 Mar 2016 10:46:58 +0100	[thread overview]
Message-ID: <56F11492.5040103@redhat.com> (raw)
In-Reply-To: <20160322100706.597dab1b.cornelia.huck@de.ibm.com>



On 22/03/2016 10:07, Cornelia Huck wrote:
> So far, we had the best results with my refactoring + the mutex/bh
> change. Two problems:
> 
> - We don't really understand yet why my refactoring helps, but passing
> the assign value is a good canditate (and it's agreed that this fixes a
> bug, I think.)
> - There's some problem with the bh, if I understood Stefan correctly.

They can be fixed with just an extra object_ref/object_unref.

I didn't understand that Tu Bo also needed the BH fix, and with that
information it makes sense.  Passing the assign value ensures that
ioeventfd remains always assigned.  With the CPU threads out of the
picture, the BH becomes enough to make everything thread-safe.

Paolo

  reply	other threads:[~2016-03-22  9:47 UTC|newest]

Thread overview: 70+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2016-03-16 10:10 [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 1/4] block: Use drained section in bdrv_set_aio_context Fam Zheng
2016-03-16 10:27   ` Paolo Bonzini
2016-03-16 10:51     ` Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 2/4] block-backend: Introduce blk_drained_begin/end Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 3/4] virtio-blk: Use blk_drained_begin/end around dataplane stop Fam Zheng
2016-03-16 10:10 ` [Qemu-devel] [PATCH 4/4] virtio-blk: Clean up start/stop with mutex and BH Fam Zheng
2016-03-17 15:00   ` [Qemu-devel] [Qemu-block] " Stefan Hajnoczi
2016-03-17 15:07     ` Paolo Bonzini
2016-03-22 12:52       ` Fam Zheng
2016-03-22 18:05         ` Paolo Bonzini
2016-03-23  8:10           ` Cornelia Huck
2016-03-23  9:08             ` Paolo Bonzini
2016-03-23  9:12               ` Christian Borntraeger
2016-03-24  8:19                 ` tu bo
2016-03-24  8:32                   ` Cornelia Huck
2016-03-24  8:47                     ` Cornelia Huck
2016-03-24  9:31                       ` Cornelia Huck
2016-03-16 10:28 ` [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop Paolo Bonzini
2016-03-16 10:49   ` Christian Borntraeger
2016-03-16 11:09     ` Paolo Bonzini
2016-03-16 11:24       ` Christian Borntraeger
2016-03-16 12:55         ` Paolo Bonzini
2016-03-16 13:38           ` Christian Borntraeger
2016-03-16 13:45             ` Paolo Bonzini
2016-03-17  0:39               ` Fam Zheng
2016-03-17 11:03                 ` tu bo
2016-03-21 10:57                   ` Fam Zheng
2016-03-21 11:15                     ` Cornelia Huck
2016-03-21 12:45                       ` Fam Zheng
2016-03-21 13:02                         ` Cornelia Huck
2016-03-21 23:45                           ` Fam Zheng
2016-03-22  8:06                             ` Cornelia Huck
2016-03-22  7:10                     ` tu bo
2016-03-22  7:18                       ` Fam Zheng
2016-03-22  9:07                         ` Cornelia Huck
2016-03-22  9:46                           ` Paolo Bonzini [this message]
2016-03-22 11:59                             ` Cornelia Huck
2016-03-22 12:11                               ` Paolo Bonzini
2016-03-22 12:54                                 ` Cornelia Huck
2016-03-17 12:22             ` tu bo
2016-03-17 12:39               ` Christian Borntraeger
2016-03-17 13:02                 ` Cornelia Huck
2016-03-17 15:02                 ` Paolo Bonzini
2016-03-17 15:07                   ` Christian Borntraeger
2016-03-17 15:15                   ` Christian Borntraeger
2016-03-17 15:16                     ` Christian Borntraeger
2016-03-17 16:08                       ` Christian Borntraeger
2016-03-18 15:03                         ` Paolo Bonzini
2016-03-21  9:42                           ` Fam Zheng
2016-03-21 11:10                             ` Christian Borntraeger
2016-03-21 12:17                             ` Cornelia Huck
2016-03-21 13:47                           ` TU BO
2016-03-21 13:54                             ` Paolo Bonzini
2016-03-21 14:19                               ` Cornelia Huck
2016-03-22  0:31                                 ` Fam Zheng
2016-03-16 11:32       ` Cornelia Huck
2016-03-16 11:48         ` Paolo Bonzini
2016-03-16 11:56           ` Cornelia Huck
2016-03-16 11:59             ` Paolo Bonzini
2016-03-16 12:22               ` Cornelia Huck
2016-03-16 12:32                 ` Paolo Bonzini
2016-03-16 12:42                   ` Cornelia Huck
2016-03-16 12:49                     ` Paolo Bonzini
2016-03-16 13:04                       ` Cornelia Huck
2016-03-16 13:10                         ` Paolo Bonzini
2016-03-16 13:14                           ` Cornelia Huck
2016-03-16 13:15                             ` Paolo Bonzini
2016-03-16 11:52         ` Cornelia Huck
2016-03-16 11:54           ` Paolo Bonzini

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