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From: Christian Borntraeger <borntraeger@de.ibm.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Fam Zheng <famz@redhat.com>,
	qemu-devel@nongnu.org
Cc: Kevin Wolf <kwolf@redhat.com>,
	qemu-block@nongnu.org, "Michael S. Tsirkin" <mst@redhat.com>,
	tubo@linux.vnet.ibm.com, Stefan Hajnoczi <stefanha@redhat.com>,
	cornelia.huck@de.ibm.com
Subject: Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop
Date: Wed, 16 Mar 2016 12:24:12 +0100	[thread overview]
Message-ID: <56E9425C.8030201@de.ibm.com> (raw)
In-Reply-To: <56E93ECE.10103@redhat.com>

On 03/16/2016 12:09 PM, Paolo Bonzini wrote:
> 
> 
> On 16/03/2016 11:49, Christian Borntraeger wrote:
>> Seems to lockup.
> 
> That's an improvement actually. :)
> 
>> Thread 3 (Thread 0x3ff888dc910 (LWP 88958)):
>> #0  0x000003ff8ca90cd4 in __lll_lock_wait () at /lib64/libpthread.so.0
>> #1  0x000003ff8ca93e74 in __lll_lock_elision () at /lib64/libpthread.so.0
> 
> Off-topic, I love how s390 backtraces always have a little bit of
> showing off in them! :)

So I understood your first remark (about _working_ transactional memory) but  I 
cannot parse your 2nd one. For Conny it is exactly the opposite, so I will let
Conny answer belows discussion ;-)



> 
>> #3  0x00000000800b713e in virtio_blk_data_plane_start (s=0xba232d80) at /home/cborntra/REPOS/qemu/hw/block/dataplane/virtio-blk.c:224
>> #4  0x00000000800b4ea0 in virtio_blk_handle_output (vdev=0xb9eee7e8, vq=0xba305270) at /home/cborntra/REPOS/qemu/hw/block/virtio-blk.c:590
>> #5  0x00000000800ef3dc in virtio_queue_notify_vq (vq=0xba305270) at /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1095
>> #6  0x00000000800f1c9c in virtio_queue_host_notifier_read (n=0xba3052c8) at /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1785
>> #7  0x00000000800f1e14 in virtio_queue_set_host_notifier_fd_handler (vq=0xba305270, assign=false, set_handler=false) at /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1817
>> #8  0x0000000080109c50 in virtio_ccw_set_guest2host_notifier (dev=0xb9eed6a0, n=0, assign=false, set_handler=false) at /home/cborntra/REPOS/qemu/hw/s390x/virtio-ccw.c:97
>> #9  0x0000000080109ef2 in virtio_ccw_stop_ioeventfd (dev=0xb9eed6a0) at /home/cborntra/REPOS/qemu/hw/s390x/virtio-ccw.c:154
> 
> One bug is here: virtio_ccw_stop_ioeventfd, in this case, should pass
> assign=true to virtio_ccw_set_guest2host_notifier.  (Assuming my
> understanding of assign=true is correct; I think it means "I'm going to
> set up another host notifier handler").
> 
> In dataplane, instead, all calls to
> virtio_queue_set_host_notifier_fd_handler and
> virtio_queue_aio_set_host_notifier_handler should have assign=true.  The
> ioeventfd is just being moved from one aiocontext to another.
> 
> Paolo
> 
>> #10 0x000000008010d5aa in virtio_ccw_set_host_notifier (d=0xb9eed6a0, n=0, assign=true) at /home/cborntra/REPOS/qemu/hw/s390x/virtio-ccw.c:1211
>> #11 0x00000000800b722c in virtio_blk_data_plane_start (s=0xba232d80) at /home/cborntra/REPOS/qemu/hw/block/dataplane/virtio-blk.c:242
>> #12 0x00000000800b4ea0 in virtio_blk_handle_output (vdev=0xb9eee7e8, vq=0xba305270) at /home/cborntra/REPOS/qemu/hw/block/virtio-blk.c:590
>> #13 0x00000000800ef3dc in virtio_queue_notify_vq (vq=0xba305270) at /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1095
>> #14 0x00000000800f1c9c in virtio_queue_host_notifier_read (n=0xba3052c8) at /home/cborntra/REPOS/qemu/hw/virtio/virtio.c:1785
>> #15 0x00000000802f1cd4 in aio_dispatch (ctx=0xb9e81c70) at /home/cborntra/REPOS/qemu/aio-posix.c:327
>> #16 0x00000000802df31c in aio_ctx_dispatch (source=0xb9e81c70, callback=0x0, user_data=0x0) at /home/cborntra/REPOS/qemu/async.c:232
> 

  reply	other threads:[~2016-03-16 11:24 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 [this message]
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
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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