From: Paolo Bonzini <pbonzini@redhat.com>
To: liu ping fan <qemulist@gmail.com>
Cc: Kevin Wolf <kwolf@redhat.com>,
Anthony Liguori <anthony@codemonkey.ws>,
Liu Ping Fan <pingfank@linux.vnet.ibm.com>,
qemu-devel@nongnu.org, Stefan Hajnoczi <stefanha@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v3 2/2] QEMUBH: make AioContext's bh re-entrant
Date: Thu, 20 Jun 2013 11:19:01 +0200 [thread overview]
Message-ID: <51C2C905.1060207@redhat.com> (raw)
In-Reply-To: <CAJnKYQkshFRK6CKxm-4dK6z3GQb9b9ZsajZWZQj1+Z0LQZ_eVg@mail.gmail.com>
Il 20/06/2013 11:12, liu ping fan ha scritto:
>> Right. You need to order ->idle writes before ->scheduled writes, and
>> add memory barriers, or alternatively use two bits in ->scheduled so
>> that you can assign both atomically.
>>
> I think just shift the position of smp_rmb/wmb in _schedule and _poll,
> we can acheive this (callbacks will not refer to ->idle)
Yes, but you also need to swap ->idle and ->scheduled assignments
(aio_bh_poll reads scheduled before idle; qemu_bh_schedule* must write
idle before scheduled).
Paolo
next prev parent reply other threads:[~2013-06-20 9:20 UTC|newest]
Thread overview: 15+ messages / expand[flat|nested] mbox.gz Atom feed top
2013-06-19 20:59 [Qemu-devel] [PATCH v3 0/2] QEMUBH: make AioContext's bh re-entrant Liu Ping Fan
2013-06-19 20:59 ` [Qemu-devel] [PATCH v3 1/2] add a header file for atomic operations Liu Ping Fan
2013-06-19 16:37 ` Richard Henderson
2013-06-19 16:42 ` Paolo Bonzini
2013-06-19 20:39 ` Torvald Riegel
2013-06-19 20:44 ` Richard Henderson
2013-06-20 8:03 ` Paolo Bonzini
2013-06-19 20:59 ` [Qemu-devel] [PATCH v3 2/2] QEMUBH: make AioContext's bh re-entrant Liu Ping Fan
2013-06-20 7:39 ` Stefan Hajnoczi
2013-06-20 8:16 ` Paolo Bonzini
2013-06-20 9:12 ` liu ping fan
2013-06-20 9:19 ` Paolo Bonzini [this message]
2013-06-20 9:41 ` liu ping fan
2013-06-20 9:45 ` Paolo Bonzini
2013-06-21 4:35 ` liu ping fan
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