From patchwork Fri Jan 10 13:29:02 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Ian Jackson X-Patchwork-Id: 11327397 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 8C74F930 for ; Fri, 10 Jan 2020 13:30:21 +0000 (UTC) Received: from lists.xenproject.org (lists.xenproject.org [192.237.175.120]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 68E382077C for ; Fri, 10 Jan 2020 13:30:21 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=citrix.com header.i=@citrix.com header.b="Eb8TosCm" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 68E382077C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=eu.citrix.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=xen-devel-bounces@lists.xenproject.org Received: from localhost ([127.0.0.1] helo=lists.xenproject.org) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ipuM2-0002BL-I6; Fri, 10 Jan 2020 13:29:34 +0000 Received: from us1-rack-iad1.inumbo.com ([172.99.69.81]) by lists.xenproject.org with esmtp (Exim 4.89) (envelope-from ) id 1ipuM0-0002A7-US for xen-devel@lists.xenproject.org; Fri, 10 Jan 2020 13:29:32 +0000 X-Inumbo-ID: 2f87359c-33ad-11ea-a2eb-bc764e2007e4 Received: from esa4.hc3370-68.iphmx.com (unknown [216.71.155.144]) by us1-rack-iad1.inumbo.com (Halon) with ESMTPS id 2f87359c-33ad-11ea-a2eb-bc764e2007e4; Fri, 10 Jan 2020 13:29:11 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=citrix.com; s=securemail; t=1578662951; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version; bh=HAh5Gp+uESpDijBcjwZlp5s66xVVTo2w8VLzP3EQSvI=; b=Eb8TosCmhIlqSikYvLDP4YyfMis5BF0dmd05lpq/Bz3bmRww16xeYroo XsBXVcPf92uj9V171B7MQwZrOeJWFD0AjRuxdp0DueUm6ajp4o6wDmkWt vYPBcrS0hEKrOjtdiyONkzE5Hihg5q2sgcCc9ZhI70G0KOvZ5+e5TuhSW 8=; Authentication-Results: esa4.hc3370-68.iphmx.com; dkim=none (message not signed) header.i=none; spf=None smtp.pra=ian.jackson@eu.citrix.com; spf=Pass smtp.mailfrom=Ian.Jackson@citrix.com; spf=None smtp.helo=postmaster@mail.citrix.com Received-SPF: None (esa4.hc3370-68.iphmx.com: no sender authenticity information available from domain of ian.jackson@eu.citrix.com) identity=pra; client-ip=162.221.158.21; receiver=esa4.hc3370-68.iphmx.com; envelope-from="Ian.Jackson@citrix.com"; x-sender="ian.jackson@eu.citrix.com"; x-conformance=sidf_compatible Received-SPF: Pass (esa4.hc3370-68.iphmx.com: domain of Ian.Jackson@citrix.com designates 162.221.158.21 as permitted sender) identity=mailfrom; client-ip=162.221.158.21; receiver=esa4.hc3370-68.iphmx.com; envelope-from="Ian.Jackson@citrix.com"; x-sender="Ian.Jackson@citrix.com"; x-conformance=sidf_compatible; x-record-type="v=spf1"; x-record-text="v=spf1 ip4:209.167.231.154 ip4:178.63.86.133 ip4:195.66.111.40/30 ip4:85.115.9.32/28 ip4:199.102.83.4 ip4:192.28.146.160 ip4:192.28.146.107 ip4:216.52.6.88 ip4:216.52.6.188 ip4:162.221.158.21 ip4:162.221.156.83 ip4:168.245.78.127 ~all" Received-SPF: None (esa4.hc3370-68.iphmx.com: no sender authenticity information available from domain of postmaster@mail.citrix.com) identity=helo; client-ip=162.221.158.21; receiver=esa4.hc3370-68.iphmx.com; envelope-from="Ian.Jackson@citrix.com"; x-sender="postmaster@mail.citrix.com"; x-conformance=sidf_compatible IronPort-SDR: 1Xz9hfuyzm6jtUOsKxdDbQyUQawiHrB917HX1uS1QSgOrZ6JJIZ96UWcBitMdGi0ZJR/Rw0t7J zT/7DNe6VHG6YeFlT/wBvn622fYnoCcWYYDhOfnDjx7dNPjcbxY1QVejIaqSSpMDLUuangrCHD 8jYCK/HzYxABkKl7iqPgEw/sVOPUY53bR7eXEkOzDESFwva53rSengqRc8sbw9Q5t81HkjPGqF +NIOkIBkGW1oNwrSmD4kQM3dyDmY3A7y2gwPp1+NGcEWCXPWJHyPeStcfOz9346jpt+2MsSxFV ZlU= X-SBRS: 2.7 X-MesageID: 11329930 X-Ironport-Server: esa4.hc3370-68.iphmx.com X-Remote-IP: 162.221.158.21 X-Policy: $RELAYED X-IronPort-AV: E=Sophos;i="5.69,417,1571716800"; d="scan'208";a="11329930" From: Ian Jackson To: Date: Fri, 10 Jan 2020 13:29:02 +0000 Message-ID: <20200110132902.29295-9-ian.jackson@eu.citrix.com> X-Mailer: git-send-email 2.11.0 In-Reply-To: <20200110132902.29295-1-ian.jackson@eu.citrix.com> References: <20200110132902.29295-1-ian.jackson@eu.citrix.com> MIME-Version: 1.0 Subject: [Xen-devel] [PATCH 8/8] libxl: event: Move poller pipe emptying to the end of afterpoll X-BeenThere: xen-devel@lists.xenproject.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: Xen developer discussion List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Cc: Anthony PERARD , Ian Jackson , George Dunlap , Wei Liu Errors-To: xen-devel-bounces@lists.xenproject.org Sender: "Xen-devel" If a timer event callback causes this poller to be woken (not very unlikely) we would go round the poll loop twice rather than once. Do the poller pipe emptying at the end; this is slightly more efficient because it can't cause any callbacks, so it happens after all the callbacks have been run. (This pipe-emptying has to happen in afterpoll rather than the apparently more logical beforepoll, because the application calling beforepoll doesn't constitute a promise to actually do anything.) Signed-off-by: Ian Jackson --- tools/libxl/libxl_event.c | 12 ++++++------ 1 file changed, 6 insertions(+), 6 deletions(-) diff --git a/tools/libxl/libxl_event.c b/tools/libxl/libxl_event.c index 4314191c3b..f59fbc719e 100644 --- a/tools/libxl/libxl_event.c +++ b/tools/libxl/libxl_event.c @@ -1326,12 +1326,6 @@ static void afterpoll_internal(libxl__egc *egc, libxl__poller *poller, fd_occurs(egc, efd, revents); } - if (afterpoll_check_fd(poller,fds,nfds, poller->wakeup_pipe[0],POLLIN)) { - poller->pipe_nonempty = 0; - int e = libxl__self_pipe_eatall(poller->wakeup_pipe[0]); - if (e) LIBXL__EVENT_DISASTER(egc, "read wakeup", e, 0); - } - for (;;) { libxl__ev_time *etime = LIBXL_TAILQ_FIRST(&CTX->etimes); if (!etime) @@ -1346,6 +1340,12 @@ static void afterpoll_internal(libxl__egc *egc, libxl__poller *poller, time_occurs(egc, etime, ERROR_TIMEDOUT); } + + if (afterpoll_check_fd(poller,fds,nfds, poller->wakeup_pipe[0],POLLIN)) { + poller->pipe_nonempty = 0; + int e = libxl__self_pipe_eatall(poller->wakeup_pipe[0]); + if (e) LIBXL__EVENT_DISASTER(egc, "read wakeup", e, 0); + } } void libxl_osevent_afterpoll(libxl_ctx *ctx, int nfds, const struct pollfd *fds,