From patchwork Thu Jun 16 14:08:08 2016 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Kevin Wolf X-Patchwork-Id: 9181161 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork.web.codeaurora.org (Postfix) with ESMTP id A90AE60760 for ; Thu, 16 Jun 2016 14:40:02 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9902B26538 for ; Thu, 16 Jun 2016 14:40:02 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8B59828362; Thu, 16 Jun 2016 14:40:02 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-6.9 required=2.0 tests=BAYES_00,RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) (using TLSv1 with cipher AES256-SHA (256/256 bits)) (No client certificate requested) by mail.wl.linuxfoundation.org (Postfix) with ESMTPS id 3BFBD26538 for ; Thu, 16 Jun 2016 14:40:02 +0000 (UTC) Received: from localhost ([::1]:49779 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDYSf-00044u-Bl for patchwork-qemu-devel@patchwork.kernel.org; Thu, 16 Jun 2016 10:40:01 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:46043) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDXyq-0007sG-IW for qemu-devel@nongnu.org; Thu, 16 Jun 2016 10:09:13 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1bDXyj-0000U7-A7 for qemu-devel@nongnu.org; Thu, 16 Jun 2016 10:09:11 -0400 Received: from mx1.redhat.com ([209.132.183.28]:34266) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1bDXyb-0000P6-K7; Thu, 16 Jun 2016 10:08:57 -0400 Received: from int-mx11.intmail.prod.int.phx2.redhat.com (int-mx11.intmail.prod.int.phx2.redhat.com [10.5.11.24]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4EFC081106; Thu, 16 Jun 2016 14:08:57 +0000 (UTC) Received: from noname.redhat.com (ovpn-116-75.ams2.redhat.com [10.36.116.75]) by int-mx11.intmail.prod.int.phx2.redhat.com (8.14.4/8.14.4) with ESMTP id u5GE8XUF003905; Thu, 16 Jun 2016 10:08:56 -0400 From: Kevin Wolf To: qemu-block@nongnu.org Date: Thu, 16 Jun 2016 16:08:08 +0200 Message-Id: <1466086108-24868-20-git-send-email-kwolf@redhat.com> In-Reply-To: <1466086108-24868-1-git-send-email-kwolf@redhat.com> References: <1466086108-24868-1-git-send-email-kwolf@redhat.com> X-Scanned-By: MIMEDefang 2.68 on 10.5.11.24 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.27]); Thu, 16 Jun 2016 14:08:57 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PULL 19/39] linux-aio: Cancel BH if not needed X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.21 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kwolf@redhat.com, qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+patchwork-qemu-devel=patchwork.kernel.org@nongnu.org Sender: "Qemu-devel" X-Virus-Scanned: ClamAV using ClamSMTP linux-aio uses a BH in order to make sure that the remaining completions are processed even in nested event loops of completion callbacks in order to avoid deadlocks. There is no need, however, to have the BH overhead for the first call into qemu_laio_completion_bh() or after all pending completions have already been processed. Therefore, this patch calls directly into qemu_laio_completion_bh() in qemu_laio_completion_cb() and cancels the BH after qemu_laio_completion_bh() has processed all pending completions. Signed-off-by: Kevin Wolf Reviewed-by: Paolo Bonzini --- block/linux-aio.c | 4 +++- 1 file changed, 3 insertions(+), 1 deletion(-) diff --git a/block/linux-aio.c b/block/linux-aio.c index fe7cece..e468960 100644 --- a/block/linux-aio.c +++ b/block/linux-aio.c @@ -149,6 +149,8 @@ static void qemu_laio_completion_bh(void *opaque) if (!s->io_q.plugged && !QSIMPLEQ_EMPTY(&s->io_q.pending)) { ioq_submit(s); } + + qemu_bh_cancel(s->completion_bh); } static void qemu_laio_completion_cb(EventNotifier *e) @@ -156,7 +158,7 @@ static void qemu_laio_completion_cb(EventNotifier *e) LinuxAioState *s = container_of(e, LinuxAioState, e); if (event_notifier_test_and_clear(&s->e)) { - qemu_bh_schedule(s->completion_bh); + qemu_laio_completion_bh(s); } }