From nobody Tue Feb 10 05:17:42 2026 Delivered-To: importer@patchew.org Received-SPF: pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) client-ip=208.118.235.17; envelope-from=qemu-devel-bounces+importer=patchew.org@nongnu.org; helo=lists.gnu.org; Authentication-Results: mx.zohomail.com; spf=pass (zoho.com: domain of gnu.org designates 208.118.235.17 as permitted sender) smtp.mailfrom=qemu-devel-bounces+importer=patchew.org@nongnu.org Return-Path: Received: from lists.gnu.org (lists.gnu.org [208.118.235.17]) by mx.zohomail.com with SMTPS id 1508348692081705.4726760460319; Wed, 18 Oct 2017 10:44:52 -0700 (PDT) Received: from localhost ([::1]:45816 helo=lists.gnu.org) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e4sOd-0008Vd-CY for importer@patchew.org; Wed, 18 Oct 2017 13:44:47 -0400 Received: from eggs.gnu.org ([2001:4830:134:3::10]:60442) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1e4sKV-0005Qm-04 for qemu-devel@nongnu.org; Wed, 18 Oct 2017 13:40:31 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1e4sKU-0001aG-5G for qemu-devel@nongnu.org; Wed, 18 Oct 2017 13:40:31 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47866) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1e4sKT-0001Zr-Tb for qemu-devel@nongnu.org; Wed, 18 Oct 2017 13:40:30 -0400 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id DC34A7EA94; Wed, 18 Oct 2017 17:40:28 +0000 (UTC) Received: from dgilbert-t530.redhat.com (ovpn-116-63.ams2.redhat.com [10.36.116.63]) by smtp.corp.redhat.com (Postfix) with ESMTP id 6ECE677D53; Wed, 18 Oct 2017 17:40:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mx1.redhat.com DC34A7EA94 Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; dmarc=none (p=none dis=none) header.from=redhat.com Authentication-Results: ext-mx04.extmail.prod.ext.phx2.redhat.com; spf=fail smtp.mailfrom=dgilbert@redhat.com From: "Dr. David Alan Gilbert (git)" To: qemu-devel@nongnu.org, kwolf@redhat.com, jdenemar@redhat.com, wangjie88@huawei.com, quintela@redhat.com, peterx@redhat.com, mreitz@redhat.com Date: Wed, 18 Oct 2017 18:40:09 +0100 Message-Id: <20171018174013.22709-4-dgilbert@redhat.com> In-Reply-To: <20171018174013.22709-1-dgilbert@redhat.com> References: <20171018174013.22709-1-dgilbert@redhat.com> X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.28]); Wed, 18 Oct 2017 17:40:29 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 Subject: [Qemu-devel] [PATCH v3 3/7] migration: Wait for semaphore before completing migration 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: fuweiwei2@huawei.com Errors-To: qemu-devel-bounces+importer=patchew.org@nongnu.org Sender: "Qemu-devel" X-ZohoMail: RSF_0 Z_629925259 SPT_0 Content-Transfer-Encoding: quoted-printable MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" From: "Dr. David Alan Gilbert" Wait for a semaphore before completing the migration, if the previously added capability was enabled. Signed-off-by: Dr. David Alan Gilbert Reviewed-by: Peter Xu --- migration/migration.c | 38 ++++++++++++++++++++++++++++++++++++++ migration/migration.h | 3 +++ 2 files changed, 41 insertions(+) diff --git a/migration/migration.c b/migration/migration.c index 86ae0292f0..6c6d5e2c75 100644 --- a/migration/migration.c +++ b/migration/migration.c @@ -1968,6 +1968,39 @@ fail: } =20 /** + * migration_maybe_pause: Pause if required to by + * migrate_pause_before_switchover called with the iothread locked + * Returns: 0 on success + */ +static int migration_maybe_pause(MigrationState *s, int *current_active_st= ate) +{ + if (!migrate_pause_before_switchover()) { + return 0; + } + + /* Since leaving this state is not atomic with posting the semaphore + * it's possible that someone could have issued multiple migrate_conti= nue + * and the semaphore is incorrectly positive at this point; + * the docs say it's undefined to reinit a semaphore that's already + * init'd, so use timedwait to eat up any existing posts. + */ + while (qemu_sem_timedwait(&s->pause_sem, 1) =3D=3D 0) { + /* This block intentionally left blank */ + } + + qemu_mutex_unlock_iothread(); + migrate_set_state(&s->state, *current_active_state, + MIGRATION_STATUS_PRE_SWITCHOVER); + qemu_sem_wait(&s->pause_sem); + migrate_set_state(&s->state, MIGRATION_STATUS_PRE_SWITCHOVER, + MIGRATION_STATUS_DEVICE); + *current_active_state =3D MIGRATION_STATUS_DEVICE; + qemu_mutex_lock_iothread(); + + return s->state =3D=3D MIGRATION_STATUS_DEVICE ? 0 : -EINVAL; +} + +/** * migration_completion: Used by migration_thread when there's not much le= ft. * The caller 'breaks' the loop when this returns. * @@ -1993,6 +2026,9 @@ static void migration_completion(MigrationState *s, i= nt current_active_state, bool inactivate =3D !migrate_colo_enabled(); ret =3D vm_stop_force_state(RUN_STATE_FINISH_MIGRATE); if (ret >=3D 0) { + ret =3D migration_maybe_pause(s, ¤t_active_state); + } + if (ret >=3D 0) { qemu_file_set_rate_limit(s->to_dst_file, INT64_MAX); ret =3D qemu_savevm_state_complete_precopy(s->to_dst_file,= false, inactivate); @@ -2373,6 +2409,7 @@ static void migration_instance_finalize(Object *obj) =20 g_free(params->tls_hostname); g_free(params->tls_creds); + qemu_sem_destroy(&ms->pause_sem); } =20 static void migration_instance_init(Object *obj) @@ -2383,6 +2420,7 @@ static void migration_instance_init(Object *obj) ms->state =3D MIGRATION_STATUS_NONE; ms->xbzrle_cache_size =3D DEFAULT_MIGRATE_CACHE_SIZE; ms->mbps =3D -1; + qemu_sem_init(&ms->pause_sem, 0); =20 params->tls_hostname =3D g_strdup(""); params->tls_creds =3D g_strdup(""); diff --git a/migration/migration.h b/migration/migration.h index 969866303e..cd988a99b9 100644 --- a/migration/migration.h +++ b/migration/migration.h @@ -121,6 +121,9 @@ struct MigrationState /* Flag set once the migration thread called bdrv_inactivate_all */ bool block_inactive; =20 + /* Migration is paused due to pause-before-switchover */ + QemuSemaphore pause_sem; + /* The semaphore is used to notify COLO thread that failover is finish= ed */ QemuSemaphore colo_exit_sem; =20 --=20 2.13.6