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Re: [PATCH v3 16/21] migration/block-dirty-bitmap: cancel migration on s
From: |
Dr. David Alan Gilbert |
Subject: |
Re: [PATCH v3 16/21] migration/block-dirty-bitmap: cancel migration on shutdown |
Date: |
Mon, 27 Jul 2020 14:21:05 +0100 |
User-agent: |
Mutt/1.14.5 (2020-06-23) |
* Vladimir Sementsov-Ogievskiy (vsementsov@virtuozzo.com) wrote:
> If target is turned off prior to postcopy finished, target crashes
> because busy bitmaps are found at shutdown.
> Canceling incoming migration helps, as it removes all unfinished (and
> therefore busy) bitmaps.
>
> Similarly on source we crash in bdrv_close_all which asserts that all
> bdrv states are removed, because bdrv states involved into dirty bitmap
> migration are referenced by it. So, we need to cancel outgoing
> migration as well.
>
> Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
> Reviewed-by: Andrey Shinkevich <andrey.shinkevich@virtuozzo.com>
> ---
> migration/migration.h | 2 ++
> migration/block-dirty-bitmap.c | 16 ++++++++++++++++
> migration/migration.c | 13 +++++++++++++
> 3 files changed, 31 insertions(+)
>
> diff --git a/migration/migration.h b/migration/migration.h
> index ab20c756f5..6c6a931d0d 100644
> --- a/migration/migration.h
> +++ b/migration/migration.h
> @@ -335,6 +335,8 @@ void migrate_send_rp_recv_bitmap(MigrationIncomingState
> *mis,
> void migrate_send_rp_resume_ack(MigrationIncomingState *mis, uint32_t value);
>
> void dirty_bitmap_mig_before_vm_start(void);
> +void dirty_bitmap_mig_cancel_outgoing(void);
> +void dirty_bitmap_mig_cancel_incoming(void);
> void migrate_add_address(SocketAddress *address);
>
> int foreach_not_ignored_block(RAMBlockIterFunc func, void *opaque);
> diff --git a/migration/block-dirty-bitmap.c b/migration/block-dirty-bitmap.c
> index c24d4614bf..a198ec7278 100644
> --- a/migration/block-dirty-bitmap.c
> +++ b/migration/block-dirty-bitmap.c
> @@ -657,6 +657,22 @@ static void cancel_incoming_locked(DBMLoadState *s)
> s->bitmaps = NULL;
> }
>
> +void dirty_bitmap_mig_cancel_outgoing(void)
> +{
> + dirty_bitmap_do_save_cleanup(&dbm_state.save);
> +}
> +
> +void dirty_bitmap_mig_cancel_incoming(void)
> +{
> + DBMLoadState *s = &dbm_state.load;
> +
> + qemu_mutex_lock(&s->lock);
> +
> + cancel_incoming_locked(s);
> +
> + qemu_mutex_unlock(&s->lock);
> +}
> +
> static void dirty_bitmap_load_complete(QEMUFile *f, DBMLoadState *s)
> {
> GSList *item;
> diff --git a/migration/migration.c b/migration/migration.c
> index 1c61428988..8fe36339db 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -188,6 +188,19 @@ void migration_shutdown(void)
> */
> migrate_fd_cancel(current_migration);
> object_unref(OBJECT(current_migration));
> +
> + /*
> + * Cancel outgoing migration of dirty bitmaps. It should
> + * at least unref used block nodes.
> + */
> + dirty_bitmap_mig_cancel_outgoing();
> +
> + /*
> + * Cancel incoming migration of dirty bitmaps. Dirty bitmaps
> + * are non-critical data, and their loss never considered as
> + * something serious.
> + */
> + dirty_bitmap_mig_cancel_incoming();
Are you sure this is the right place to put them - I'm thinking that
perhaps the object_unref of current_migration should still be after
them?
Dave
> }
>
> /* For outgoing */
> --
> 2.21.0
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK
[PATCH v3 16/21] migration/block-dirty-bitmap: cancel migration on shutdown, Vladimir Sementsov-Ogievskiy, 2020/07/24
- Re: [PATCH v3 16/21] migration/block-dirty-bitmap: cancel migration on shutdown,
Dr. David Alan Gilbert <=
[PATCH v3 17/21] migration/savevm: don't worry if bitmap migration postcopy failed, Vladimir Sementsov-Ogievskiy, 2020/07/24