From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48945) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ag9Yt-0005an-7x for qemu-devel@nongnu.org; Wed, 16 Mar 2016 07:24:24 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ag9Yq-0006JR-Ki for qemu-devel@nongnu.org; Wed, 16 Mar 2016 07:24:23 -0400 Received: from e06smtp12.uk.ibm.com ([195.75.94.108]:39950) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1ag9Yq-0006Ht-BR for qemu-devel@nongnu.org; Wed, 16 Mar 2016 07:24:20 -0400 Received: from localhost by e06smtp12.uk.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 16 Mar 2016 11:24:17 -0000 References: <1458123018-18651-1-git-send-email-famz@redhat.com> <56E9355A.5070700@redhat.com> <56E93A22.1080102@de.ibm.com> <56E93ECE.10103@redhat.com> From: Christian Borntraeger Message-ID: <56E9425C.8030201@de.ibm.com> Date: Wed, 16 Mar 2016 12:24:12 +0100 MIME-Version: 1.0 In-Reply-To: <56E93ECE.10103@redhat.com> Content-Type: text/plain; charset=windows-1252 Content-Transfer-Encoding: 7bit Subject: Re: [Qemu-devel] [PATCH 0/4] Tweaks around virtio-blk start/stop List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: Paolo Bonzini , Fam Zheng , qemu-devel@nongnu.org Cc: Kevin Wolf , qemu-block@nongnu.org, "Michael S. Tsirkin" , tubo@linux.vnet.ibm.com, Stefan Hajnoczi , cornelia.huck@de.ibm.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 >