From mboxrd@z Thu Jan  1 00:00:00 1970
Received: from eggs.gnu.org ([2001:4830:134:3::10]:32982)
	by lists.gnu.org with esmtp (Exim 4.71)
	(envelope-from <famz@redhat.com>) id 1ZH5mW-0005jy-4K
	for qemu-devel@nongnu.org; Mon, 20 Jul 2015 03:46:36 -0400
Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)
	(envelope-from <famz@redhat.com>) id 1ZH5mQ-0007ZF-8v
	for qemu-devel@nongnu.org; Mon, 20 Jul 2015 03:46:36 -0400
Received: from mx1.redhat.com ([209.132.183.28]:43333)
	by eggs.gnu.org with esmtp (Exim 4.71)
	(envelope-from <famz@redhat.com>) id 1ZH5mQ-0007Z1-3j
	for qemu-devel@nongnu.org; Mon, 20 Jul 2015 03:46:30 -0400
Received: from int-mx10.intmail.prod.int.phx2.redhat.com
	(int-mx10.intmail.prod.int.phx2.redhat.com [10.5.11.23])
	by mx1.redhat.com (Postfix) with ESMTPS id DEED98E71A
	for <qemu-devel@nongnu.org>; Mon, 20 Jul 2015 07:46:28 +0000 (UTC)
Date: Mon, 20 Jul 2015 15:46:25 +0800
From: Fam Zheng <famz@redhat.com>
Message-ID: <20150720074625.GA20738@ad.nay.redhat.com>
References: <1437370031-9070-1-git-send-email-pbonzini@redhat.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <1437370031-9070-1-git-send-email-pbonzini@redhat.com>
Subject: Re: [Qemu-devel] [PATCH v2] AioContext: fix broken placement of
 event_notifier_test_and_clear
List-Id: <qemu-devel.nongnu.org>
List-Unsubscribe: <https://lists.nongnu.org/mailman/options/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=unsubscribe>
List-Archive: <http://lists.nongnu.org/archive/html/qemu-devel>
List-Post: <mailto:qemu-devel@nongnu.org>
List-Help: <mailto:qemu-devel-request@nongnu.org?subject=help>
List-Subscribe: <https://lists.nongnu.org/mailman/listinfo/qemu-devel>,
	<mailto:qemu-devel-request@nongnu.org?subject=subscribe>
To: Paolo Bonzini <pbonzini@redhat.com>
Cc: kwolf@redhat.com, lersek@redhat.com, qemu-devel@nongnu.org, stefanha@redhat.com, rjones@redhat.com

On Mon, 07/20 07:27, Paolo Bonzini wrote:
> diff --git a/aio-win32.c b/aio-win32.c
> index ea655b0..7afc999 100644
> --- a/aio-win32.c
> +++ b/aio-win32.c
> @@ -337,10 +337,11 @@ bool aio_poll(AioContext *ctx, bool blocking)
>              aio_context_acquire(ctx);
>          }
>  
> -        if (first && aio_bh_poll(ctx)) {
> -            progress = true;
> +        if (first) {
> +            event_notifier_test_and_clear(&ctx->notifier);

I'm looking at optimizing it but I don't fully understand the relationship
between aio_prepare and WaitForMultipleObjects. Do they get the same set of
events? What if a new event comes in between, for example, thread worker calls
aio_notify()?

Fam

> +            progress |= aio_bh_poll(ctx);
> +            first = false;
>          }
> -        first = false;
>  
>          /* if we have any signaled events, dispatch event */
>          event = NULL;