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Date: Wed, 12 Oct 2016 18:32:03 +0800
From: Changlong Xie <xiecl.fnst@cn.fujitsu.com>
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Subject: Re: [Qemu-devel] [PATCH] nbd: Use CoQueue for free_sema instead of
 CoMutex
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To: qemu devel <qemu-devel@nongnu.org>, qemu block <qemu-block@nongnu.org>, Stefan Hajnoczi <stefanha@redhat.com>, Fam Zheng <famz@redhat.com>, Max Reitz <mreitz@redhat.com>, Kevin Wolf <kwolf@redhat.com>, Eric Blake <eblake@redhat.com>
Cc: zhanghailiang <zhang.zhanghailiang@huawei.com>

On 10/12/2016 06:18 PM, Changlong Xie wrote:
> ----------------------------------------------------------------------------------------
> time request       Actions
> 29   15(most case) in_flight=15, Coroutine=C15, free_sema->holder=C17, mutex->locked=false
> ----------------------------------------------------------------------------------------
>
> Per Paolo's suggestion "The simplest fix is to change it to CoQueue, which is like a condition
> variable", this patch replaces CoMutex with CoQueue.
>
> Cc: Wen Congyang<wency@cn.fujitsu.com>
> Reported-by: zhanghailiang<zhang.zhanghailiang@huawei.com>
> Suggested-by: Paolo Bonzini<pbonzini@redhat.com>
> Signed-off-by: Changlong Xie<xiecl.fnst@cn.fujitsu.com>
> ---

Please refer to:

http://lists.nongnu.org/archive/html/qemu-devel/2016-10/msg02172.html