From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-8.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 297F1C43603 for ; Wed, 18 Dec 2019 16:38:00 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (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 E62A12146E for ; Wed, 18 Dec 2019 16:37:59 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="d1pSW1j3" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org E62A12146E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:57024 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ihcKk-0000DZ-GZ for qemu-devel@archiver.kernel.org; Wed, 18 Dec 2019 11:37:58 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:43646) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1ihcG8-00035e-8v for qemu-devel@nongnu.org; Wed, 18 Dec 2019 11:33:13 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1ihcG6-0000TD-TZ for qemu-devel@nongnu.org; Wed, 18 Dec 2019 11:33:12 -0500 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:57709 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1ihcG6-0000Mx-Hp for qemu-devel@nongnu.org; Wed, 18 Dec 2019 11:33:10 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1576686790; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=fe6XOT6VfRMJNCTI42hMa/cSWFh/I/xhgIf+gPIlwtU=; b=d1pSW1j3172FY2LD+olMkzRd3rDY6HM0MQM8Y0sBpNDxsZknEM8IckBPZRC57h3V3DxhNZ 6T2fhlldTAoAzkCtaZaHNefLGqUNGZV/bGcCIryt09lfY1TE/Q/ZWKZ2lvhuNsH6bW9/O4 FP1rWi0JpcNJc3E3rIopx4q7bAe9vrM= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-246-WqdrA8_JMDyqEbyNB7eMMw-1; Wed, 18 Dec 2019 11:33:08 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 3DBA7189EB23 for ; Wed, 18 Dec 2019 16:33:07 +0000 (UTC) Received: from work-vm (unknown [10.36.118.19]) by smtp.corp.redhat.com (Postfix) with ESMTPS id B03C668890; Wed, 18 Dec 2019 16:33:03 +0000 (UTC) Date: Wed, 18 Dec 2019 16:33:01 +0000 From: "Dr. David Alan Gilbert" To: Juan Quintela Subject: Re: [PATCH 4/4] migration: Make sure that we don't call write() in case of error Message-ID: <20191218163301.GJ3707@work-vm> References: <20191218050439.5989-1-quintela@redhat.com> <20191218050439.5989-5-quintela@redhat.com> MIME-Version: 1.0 In-Reply-To: <20191218050439.5989-5-quintela@redhat.com> User-Agent: Mutt/1.13.0 (2019-11-30) X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-MC-Unique: WqdrA8_JMDyqEbyNB7eMMw-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=us-ascii Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 205.139.110.120 X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Laurent Vivier , Paolo Bonzini , Thomas Huth , qemu-devel@nongnu.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Juan Quintela (quintela@redhat.com) wrote: > If we are exiting due to an error/finish/.... Just don't try to even > touch the channel with one IO operation. >=20 > Signed-off-by: Juan Quintela > --- > migration/ram.c | 19 +++++++++++++++++++ > 1 file changed, 19 insertions(+) >=20 > diff --git a/migration/ram.c b/migration/ram.c > index 4b44578e57..909ef6d237 100644 > --- a/migration/ram.c > +++ b/migration/ram.c > @@ -1601,6 +1601,12 @@ struct { > QemuSemaphore channels_ready; > /* multifd ops */ > MultiFDMethods *ops; > + /* > + * Have we already run terminate threads. There is a race when it > + * happens that we got one error while we are exiting. > + * We will use atomic operations. Only valid values are 0 and 1. > + */ > + int exiting; > } *multifd_send_state; > =20 > /* > @@ -1629,6 +1635,10 @@ static int multifd_send_pages(RAMState *rs) > MultiFDPages_t *pages =3D multifd_send_state->pages; > uint64_t transferred; > =20 > + if (atomic_read(&multifd_send_state->exiting)) { > + return -1; > + } > + > qemu_sem_wait(&multifd_send_state->channels_ready); > for (i =3D next_channel;; i =3D (i + 1) % migrate_multifd_channels()= ) { > p =3D &multifd_send_state->params[i]; > @@ -1710,6 +1720,10 @@ static void multifd_send_terminate_threads(Error *= err) > } > } > =20 > + if (atomic_xchg(&multifd_send_state->exiting, 1)) { > + return; > + } That could do with a comment on it; I think what you're saying is 'don't do send_terminate_threads twice' With a comment, Reviewed-by: Dr. David Alan Gilbert > for (i =3D 0; i < migrate_multifd_channels(); i++) { > MultiFDSendParams *p =3D &multifd_send_state->params[i]; > =20 > @@ -1824,6 +1838,10 @@ static void *multifd_send_thread(void *opaque) > =20 > while (true) { > qemu_sem_wait(&p->sem); > + > + if (atomic_read(&multifd_send_state->exiting)) { > + break; > + } > qemu_mutex_lock(&p->mutex); > =20 > if (p->pending_job) { > @@ -1938,6 +1956,7 @@ int multifd_save_setup(Error **errp) > multifd_send_state->pages =3D multifd_pages_init(page_count); > qemu_sem_init(&multifd_send_state->channels_ready, 0); > multifd_send_state->ops =3D multifd_ops[migrate_multifd_method()]; > + atomic_set(&multifd_send_state->exiting, 0); > =20 > for (i =3D 0; i < thread_count; i++) { > MultiFDSendParams *p =3D &multifd_send_state->params[i]; > --=20 > 2.23.0 >=20 -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK