Re: [PATCH v5 08/24] replay: Fix migration use of clock

[Alex Bennée]

Nicholas Piggin <npiggin@gmail.com> writes:

> Migration reads host clocks when not holding the replay_mutex, which
> asserts when recording a trace. It seems that these migration times
> should be host times like other statistics in MigrationState.

s/host/CLOCK_HOST/ and s/host/CLOCK_REALTIME/ but its a confusing
sentence. If the MigrationState is guest visible it should be
QEMU_CLOCK_VIRTUAL surely?

> These
> do not require the replay_mutex.
>
> Signed-off-by: Nicholas Piggin <npiggin@gmail.com>
> ---
>  migration/migration.c | 8 ++++----
>  1 file changed, 4 insertions(+), 4 deletions(-)
>
> diff --git a/migration/migration.c b/migration/migration.c
> index 644e073b7d..2c286ccf63 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -3424,7 +3424,7 @@ static void *migration_thread(void *opaque)
>  {
>      MigrationState *s = opaque;
>      MigrationThread *thread = NULL;
> -    int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> +    int64_t setup_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>      MigThrError thr_error;
>      bool urgent = false;
>  
> @@ -3476,7 +3476,7 @@ static void *migration_thread(void *opaque)
>      qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
>                                 MIGRATION_STATUS_ACTIVE);
>  
> -    s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
> +    s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - setup_start;
>  
>      trace_migration_thread_setup_complete();
>  
> @@ -3555,7 +3555,7 @@ static void *bg_migration_thread(void *opaque)
>  
>      migration_rate_set(RATE_LIMIT_DISABLED);
>  
> -    setup_start = qemu_clock_get_ms(QEMU_CLOCK_HOST);
> +    setup_start = qemu_clock_get_ms(QEMU_CLOCK_REALTIME);
>      /*
>       * We want to save vmstate for the moment when migration has been
>       * initiated but also we want to save RAM content while VM is running.
> @@ -3588,7 +3588,7 @@ static void *bg_migration_thread(void *opaque)
>      qemu_savevm_wait_unplug(s, MIGRATION_STATUS_SETUP,
>                                 MIGRATION_STATUS_ACTIVE);
>  
> -    s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_HOST) - setup_start;
> +    s->setup_time = qemu_clock_get_ms(QEMU_CLOCK_REALTIME) - setup_start;
>  
>      trace_migration_thread_setup_complete();

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro