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Date: Mon, 19 Aug 2013 14:00:50 +0200
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] Using aio_poll for timer carrier threads
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To: Jan Kiszka <jan.kiszka@siemens.com>
Cc: Kevin Wolf <kwolf@redhat.com>, Anthony Liguori <aliguori@us.ibm.com>, Alex Bligh <alex@alex.org.uk>, Stefan Hajnoczi <stefanha@gmail.com>, qemu-devel <qemu-devel@nongnu.org>, liu ping fan <qemulist@gmail.com>, Stefan Hajnoczi <stefanha@redhat.com>, MORITA Kazutaka <morita.kazutaka@lab.ntt.co.jp>, Richard Henderson <rth@twiddle.net>

Il 14/08/2013 14:32, Jan Kiszka ha scritto:
> I still need to check more corner cases as timer dequeuing can now race
> with the handler execution, ie. a dequeued timer can still see one more
> handler run after timer_del returned. That's a property one can easily
> take into account when writing device models, but it has to be kept in
> mind that it's different from current behavior.
> 
> Updated queue is at git://git.kiszka.org/qemu.git queues/rt.new3 again.

I took a look here, there are several patches that I guess are basically
ready... two random things I noticed:

(1) rcu_init() must be called in rcutorture too

(2) there are several load/store functions in exec.c that do not go
through address_space_rw.  These would not call
qemu_flush_coalesced_mmio_buffer() after your patch "provide
address_space_rw_unlocked".  I think that in most cases the solution
should be to make these functions go through address_space_rw.

Paolo