Re: [PATCH v1 08/17] migration/colo: Use ram_block_discard_set_broken()

Dr. David Alan Gilbert
2020-05-15T13:58:59Z

* David Hildenbrand (david@redhat.com) wrote:
> COLO will copy all memory in a RAM block, mark discarding of RAM broken.
>
> Cc: "Michael S. Tsirkin" <mst@redhat.com>
> Cc: Hailiang Zhang <zhang.zhanghailiang@huawei.com>
> Cc: Juan Quintela <quintela@redhat.com>
> Cc: "Dr. David Alan Gilbert" <dgilbert@redhat.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
> include/migration/colo.h | 2 +-
> migration/migration.c | 8 +++++++-
> migration/savevm.c | 11 +++++++++--
> 3 files changed, 17 insertions(+), 4 deletions(-)
>
> diff --git a/include/migration/colo.h b/include/migration/colo.h
> index 1636e6f907..768e1f04c3 100644
> --- a/include/migration/colo.h
> +++ b/include/migration/colo.h
> @@ -25,7 +25,7 @@ void migrate_start_colo_process(MigrationState *s);
> bool migration_in_colo_state(void);
>
> /* loadvm */
> -void migration_incoming_enable_colo(void);
> +int migration_incoming_enable_colo(void);
> void migration_incoming_disable_colo(void);
> bool migration_incoming_colo_enabled(void);
> void *colo_process_incoming_thread(void *opaque);
> diff --git a/migration/migration.c b/migration/migration.c
> index 177cce9e95..f6830e4620 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -338,12 +338,18 @@ bool migration_incoming_colo_enabled(void)
>
> void migration_incoming_disable_colo(void)
> {
> + ram_block_discard_set_broken(false);
> migration_colo_enabled = false;
> }
>
> -void migration_incoming_enable_colo(void)
> +int migration_incoming_enable_colo(void)
> {
> + if (ram_block_discard_set_broken(true)) {
> + error_report("COLO: cannot set discarding of RAM broken");

I'd prefer 'COLO: cannot disable RAM discard'

'broken' suggests the user has to go and fix something or report a bug
or something.

Other than that:

Reviewed-by: Dr. David Alan Gilbert <dgilbert@redhat.com>

Dave

> + return -EBUSY;
> + }
> migration_colo_enabled = true;
> + return 0;
> }
>
> void migrate_add_address(SocketAddress *address)
> diff --git a/migration/savevm.c b/migration/savevm.c
> index c00a6807d9..19b4f9600d 100644
> --- a/migration/savevm.c
> +++ b/migration/savevm.c
> @@ -2111,8 +2111,15 @@ static int loadvm_handle_recv_bitmap(MigrationIncomingState *mis,
>
> static int loadvm_process_enable_colo(MigrationIncomingState *mis)
> {
> - migration_incoming_enable_colo();
> - return colo_init_ram_cache();
> + int ret = migration_incoming_enable_colo();
> +
> + if (!ret) {
> + ret = colo_init_ram_cache();
> + if (ret) {
> + migration_incoming_disable_colo();
> + }
> + }
> + return ret;
> }
>
> /*
> --
> 2.25.3
>
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK