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=-8.3 required=3.0 tests=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 5B1EAECE58D for ; Fri, 11 Oct 2019 17:55:28 +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 31EB8206A1 for ; Fri, 11 Oct 2019 17:55:28 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 31EB8206A1 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]:54984 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIz8R-0005iM-0m for qemu-devel@archiver.kernel.org; Fri, 11 Oct 2019 13:55:27 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47239) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iIySG-0002lS-4U for qemu-devel@nongnu.org; Fri, 11 Oct 2019 13:11:53 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iIySD-0007it-UE for qemu-devel@nongnu.org; Fri, 11 Oct 2019 13:11:51 -0400 Received: from mx1.redhat.com ([209.132.183.28]:47142) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iIySD-0007ij-LA for qemu-devel@nongnu.org; Fri, 11 Oct 2019 13:11:49 -0400 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id A4AB45946B; Fri, 11 Oct 2019 17:11:48 +0000 (UTC) Received: from work-vm (ovpn-117-210.ams2.redhat.com [10.36.117.210]) by smtp.corp.redhat.com (Postfix) with ESMTPS id A83004536; Fri, 11 Oct 2019 17:11:35 +0000 (UTC) Date: Fri, 11 Oct 2019 18:11:33 +0100 From: "Dr. David Alan Gilbert" To: Jens Freimann Subject: Re: [PATCH v3 07/10] migration: add new migration state wait-unplug Message-ID: <20191011171133.GU3354@work-vm> References: <20191011112015.11785-1-jfreimann@redhat.com> <20191011112015.11785-8-jfreimann@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191011112015.11785-8-jfreimann@redhat.com> User-Agent: Mutt/1.12.1 (2019-06-15) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.39]); Fri, 11 Oct 2019 17:11:48 +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 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: ehabkost@redhat.com, mst@redhat.com, aadam@redhat.com, qemu-devel@nongnu.org, alex.williamson@redhat.com, laine@redhat.com, ailan@redhat.com, parav@mellanox.com Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" * Jens Freimann (jfreimann@redhat.com) wrote: > This patch adds a new migration state called wait-unplug. It is entered > after the SETUP state and will transition into ACTIVE once all devices > were succesfully unplugged from the guest. > > So if a guest doesn't respond or takes long to honor the unplug request > the user will see the migration state 'wait-unplug'. > > In the migration thread we query failover devices if they're are still > pending the guest unplug. When all are unplugged the migration > continues. We give it a defined number of iterations including small > waiting periods before we proceed. > > Signed-off-by: Jens Freimann > --- > include/migration/vmstate.h | 2 ++ > migration/migration.c | 34 ++++++++++++++++++++++++++++++++++ > migration/migration.h | 3 +++ > migration/savevm.c | 36 ++++++++++++++++++++++++++++++++++++ > migration/savevm.h | 1 + > qapi/migration.json | 5 ++++- > 6 files changed, 80 insertions(+), 1 deletion(-) > > diff --git a/include/migration/vmstate.h b/include/migration/vmstate.h > index 1fbfd099dd..39ef125225 100644 > --- a/include/migration/vmstate.h > +++ b/include/migration/vmstate.h > @@ -186,6 +186,8 @@ struct VMStateDescription { > int (*pre_save)(void *opaque); > int (*post_save)(void *opaque); > bool (*needed)(void *opaque); > + bool (*dev_unplug_pending)(void *opaque); > + > const VMStateField *fields; > const VMStateDescription **subsections; > }; > diff --git a/migration/migration.c b/migration/migration.c > index 5f7e4d15e9..a17d9fb990 100644 > --- a/migration/migration.c > +++ b/migration/migration.c > @@ -52,9 +52,14 @@ > #include "hw/qdev-properties.h" > #include "monitor/monitor.h" > #include "net/announce.h" > +#include "qemu/queue.h" > > #define MAX_THROTTLE (32 << 20) /* Migration transfer speed throttling */ > > +/* Time in milliseconds to wait for guest OS to unplug PCI device */ > +#define FAILOVER_GUEST_UNPLUG_WAIT 10000 > +#define FAILOVER_UNPLUG_RETRIES 5 > + > /* Amount of time to allocate to each "chunk" of bandwidth-throttled > * data. */ > #define BUFFER_DELAY 100 > @@ -954,6 +959,9 @@ static void fill_source_migration_info(MigrationInfo *info) > case MIGRATION_STATUS_CANCELLED: > info->has_status = true; > break; > + case MIGRATION_STATUS_WAIT_UNPLUG: > + info->has_status = true; > + break; > } > info->status = s->state; > } > @@ -1695,6 +1703,7 @@ bool migration_is_idle(void) > case MIGRATION_STATUS_COLO: > case MIGRATION_STATUS_PRE_SWITCHOVER: > case MIGRATION_STATUS_DEVICE: > + case MIGRATION_STATUS_WAIT_UNPLUG: > return false; > case MIGRATION_STATUS__MAX: > g_assert_not_reached(); > @@ -3224,6 +3233,8 @@ static void *migration_thread(void *opaque) > int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST); > MigThrError thr_error; > bool urgent = false; > + bool all_unplugged = true; > + int i = 0; > > rcu_register_thread(); > > @@ -3260,6 +3271,27 @@ static void *migration_thread(void *opaque) > > qemu_savevm_state_setup(s->to_dst_file); > > + migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, > + MIGRATION_STATUS_WAIT_UNPLUG); I think I'd prefer if you only went into this state if you had any devices that were going to need unplugging. > + while (i < FAILOVER_UNPLUG_RETRIES && > + s->state == MIGRATION_STATUS_WAIT_UNPLUG) { > + i++; > + qemu_sem_timedwait(&s->wait_unplug_sem, FAILOVER_GUEST_UNPLUG_WAIT); > + all_unplugged = qemu_savevm_state_guest_unplug_pending(); > + if (all_unplugged) { > + break; > + } > + } > + > + if (all_unplugged) { > + migrate_set_state(&s->state, MIGRATION_STATUS_WAIT_UNPLUG, > + MIGRATION_STATUS_ACTIVE); > + } else { > + migrate_set_state(&s->state, MIGRATION_STATUS_WAIT_UNPLUG, > + MIGRATION_STATUS_CANCELLING); > + } I think you can get rid of both the timeout and the count and just make sure that migrate_cancel works at this point. This pushes the problem up a layer, which I think is fine. > s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start; > migrate_set_state(&s->state, MIGRATION_STATUS_SETUP, > MIGRATION_STATUS_ACTIVE); > @@ -3508,6 +3540,7 @@ static void migration_instance_finalize(Object *obj) > qemu_mutex_destroy(&ms->qemu_file_lock); > g_free(params->tls_hostname); > g_free(params->tls_creds); > + qemu_sem_destroy(&ms->wait_unplug_sem); > qemu_sem_destroy(&ms->rate_limit_sem); > qemu_sem_destroy(&ms->pause_sem); > qemu_sem_destroy(&ms->postcopy_pause_sem); > @@ -3553,6 +3586,7 @@ static void migration_instance_init(Object *obj) > qemu_sem_init(&ms->postcopy_pause_rp_sem, 0); > qemu_sem_init(&ms->rp_state.rp_sem, 0); > qemu_sem_init(&ms->rate_limit_sem, 0); > + qemu_sem_init(&ms->wait_unplug_sem, 0); > qemu_mutex_init(&ms->qemu_file_lock); > } > > diff --git a/migration/migration.h b/migration/migration.h > index 4f2fe193dc..79b3dda146 100644 > --- a/migration/migration.h > +++ b/migration/migration.h > @@ -206,6 +206,9 @@ struct MigrationState > /* Flag set once the migration thread called bdrv_inactivate_all */ > bool block_inactive; > > + /* Migration is waiting for guest to unplug device */ > + QemuSemaphore wait_unplug_sem; > + > /* Migration is paused due to pause-before-switchover */ > QemuSemaphore pause_sem; > > diff --git a/migration/savevm.c b/migration/savevm.c > index bb9462a54d..26e5bde687 100644 > --- a/migration/savevm.c > +++ b/migration/savevm.c > @@ -942,6 +942,20 @@ static void qemu_savevm_command_send(QEMUFile *f, > qemu_fflush(f); > } > > +static int qemu_savevm_nr_failover_devices(void) > +{ > + SaveStateEntry *se; > + int n = 0; > + > + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { > + if (se->vmsd && se->vmsd->dev_unplug_pending) { > + n++; > + } > + } > + > + return n; > +} > + > void qemu_savevm_send_colo_enable(QEMUFile *f) > { > trace_savevm_send_colo_enable(); > @@ -1113,6 +1127,28 @@ void qemu_savevm_state_header(QEMUFile *f) > } > } > > +bool qemu_savevm_state_guest_unplug_pending(void) > +{ > + int nr_failover_devs; > + SaveStateEntry *se; > + bool ret = false; > + int n = 0; > + > + nr_failover_devs = qemu_savevm_nr_failover_devices(); > + > + QTAILQ_FOREACH(se, &savevm_state.handlers, entry) { > + if (!se->vmsd || !se->vmsd->dev_unplug_pending) { > + continue; > + } > + ret = se->vmsd->dev_unplug_pending(se->opaque); > + if (!ret) { > + n++; > + } > + } > + > + return n == nr_failover_devs; > +} > + > void qemu_savevm_state_setup(QEMUFile *f) > { > SaveStateEntry *se; > diff --git a/migration/savevm.h b/migration/savevm.h > index 51a4b9caa8..ba64a7e271 100644 > --- a/migration/savevm.h > +++ b/migration/savevm.h > @@ -31,6 +31,7 @@ > > bool qemu_savevm_state_blocked(Error **errp); > void qemu_savevm_state_setup(QEMUFile *f); > +bool qemu_savevm_state_guest_unplug_pending(void); > int qemu_savevm_state_resume_prepare(MigrationState *s); > void qemu_savevm_state_header(QEMUFile *f); > int qemu_savevm_state_iterate(QEMUFile *f, bool postcopy); > diff --git a/qapi/migration.json b/qapi/migration.json > index 52e69e2868..5a06cd489f 100644 > --- a/qapi/migration.json > +++ b/qapi/migration.json > @@ -133,6 +133,9 @@ > # @device: During device serialisation when pause-before-switchover is enabled > # (since 2.11) > # > +# @wait-unplug: wait for device unplug request by guest OS to be completed. > +# (since 4.2) > +# > # Since: 2.3 > # > ## > @@ -140,7 +143,7 @@ > 'data': [ 'none', 'setup', 'cancelling', 'cancelled', > 'active', 'postcopy-active', 'postcopy-paused', > 'postcopy-recover', 'completed', 'failed', 'colo', > - 'pre-switchover', 'device' ] } > + 'pre-switchover', 'device', 'wait-unplug' ] } > > ## > # @MigrationInfo: > -- > 2.21.0 > -- Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK