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Date: Thu, 28 Nov 2013 12:31:29 +0100
From: Paolo Bonzini <pbonzini@redhat.com>
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Subject: Re: [Qemu-devel] [RFC] create a single workqueue for each vm to
 update vm irq routing table
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To: Gleb Natapov <gleb@minantech.com>
Cc: Avi Kivity <avi@cloudius-systems.com>, "Huangweidong (C)" <weidong.huang@huawei.com>, Gleb Natapov <gleb@redhat.com>, KVM <kvm@vger.kernel.org>, "Michael S. Tsirkin" <mst@redhat.com>, "Zhanghaoyu (A)" <haoyu.zhang@huawei.com>, Luonengjun <luonengjun@huawei.com>, "qemu-devel@nongnu.org" <qemu-devel@nongnu.org>, Zanghongyong <zanghongyong@huawei.com>, Avi Kivity <avi.kivity@gmail.com>, "Jinxin (F)" <jinxin712@huawei.com>

Il 28/11/2013 12:23, Gleb Natapov ha scritto:
>>> > > Unless what ? :) Unless reader is scheduled out?
>> > 
>> > Yes.  Or unless my brain is scheduled out in the middle of a sentence.
>> > 
> So we will have to disable preemption in a reader to prevent big latencies for
> a writer, no?

I don't think that's necessary.  The writer itself could also be
scheduled out, and the reader critical sections are really small.  Let's
wait for Zhang to try SRCU and report back.

Paolo