Re: [RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-09 Thread Stefan Hajnoczi
On Tue, Apr 07, 2020 at 10:07:41AM -0400, Paolo Bonzini wrote: > ARM machines and other weakly-ordered architectures have been suffering > for a long time from hangs in qemu-img and qemu-io. For QEMU binaries > these are mitigated by the timers that sooner or later fire in the main > loop, but the

Re: [RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-08 Thread Ying Fang
On 2020/4/8 23:05, Paolo Bonzini wrote: On 08/04/20 11:12, Ying Fang wrote: On 2020/4/7 22:07, Paolo Bonzini wrote: ARM machines and other weakly-ordered architectures have been suffering for a long time from hangs in qemu-img and qemu-io.  For QEMU binaries these are mitigated by the timers

Re: [RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-08 Thread Paolo Bonzini
On 08/04/20 11:12, Ying Fang wrote: > On 2020/4/7 22:07, Paolo Bonzini wrote: >> ARM machines and other weakly-ordered architectures have been suffering >> for a long time from hangs in qemu-img and qemu-io.  For QEMU binaries >> these are mitigated by the timers that sooner or later fire in the ma

Re: [RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-08 Thread Ying Fang
On 2020/4/7 22:07, Paolo Bonzini wrote: ARM machines and other weakly-ordered architectures have been suffering for a long time from hangs in qemu-img and qemu-io. For QEMU binaries these are mitigated by the timers that sooner or later fire in the main loop, but these will not happen for the

[RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-07 Thread Paolo Bonzini
ARM machines and other weakly-ordered architectures have been suffering for a long time from hangs in qemu-img and qemu-io. For QEMU binaries these are mitigated by the timers that sooner or later fire in the main loop, but these will not happen for the tools and probably not with I/O threads eith

Re: [RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-07 Thread Stefan Hajnoczi
On Mon, Apr 06, 2020 at 03:13:16PM -0400, Paolo Bonzini wrote: > Patch 4 fixes qemu-img and qemu-io hangs on weakly-ordered architectures. > Patch 1-3 are related docs fixes and improvements. > > This is RFC because it relies on the iothread being locked during aio_poll > on the main AioContext.

[RFC PATCH 0/4] async: fix hangs on weakly-ordered architectures

2020-04-06 Thread Paolo Bonzini
Patch 4 fixes qemu-img and qemu-io hangs on weakly-ordered architectures. Patch 1-3 are related docs fixes and improvements. This is RFC because it relies on the iothread being locked during aio_poll on the main AioContext. If I add assertions for this however I see a failure for test 267, so I a