Re: [PATCH 20/20] tests: Add postcopy preempt test

["Dr. David Alan Gilbert" <dgilbert@redhat.com>]

* Peter Xu (peterx@redhat.com) wrote:
> Two tests are added: a normal postcopy preempt test, and a recovery test.

Yes, this is difficult; without hugepages the tests are limited; did you
see if this test actually causes pages to go down the fast path?



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

> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  tests/qtest/migration-test.c | 39 ++++++++++++++++++++++++++++++++++--
>  1 file changed, 37 insertions(+), 2 deletions(-)
> 
> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> index 7b42f6fd90..5053b40589 100644
> --- a/tests/qtest/migration-test.c
> +++ b/tests/qtest/migration-test.c
> @@ -470,6 +470,7 @@ typedef struct {
>       */
>      bool hide_stderr;
>      bool use_shmem;
> +    bool postcopy_preempt;
>      /* only launch the target process */
>      bool only_target;
>      /* Use dirty ring if true; dirty logging otherwise */
> @@ -673,6 +674,11 @@ static int migrate_postcopy_prepare(QTestState **from_ptr,
>      migrate_set_capability(to, "postcopy-ram", true);
>      migrate_set_capability(to, "postcopy-blocktime", true);
>  
> +    if (args->postcopy_preempt) {
> +        migrate_set_capability(from, "postcopy-preempt", true);
> +        migrate_set_capability(to, "postcopy-preempt", true);
> +    }
> +
>      /* We want to pick a speed slow enough that the test completes
>       * quickly, but that it doesn't complete precopy even on a slow
>       * machine, so also set the downtime.
> @@ -719,13 +725,29 @@ static void test_postcopy(void)
>      migrate_postcopy_complete(from, to);
>  }
>  
> -static void test_postcopy_recovery(void)
> +static void test_postcopy_preempt(void)
> +{
> +    MigrateStart *args = migrate_start_new();
> +    QTestState *from, *to;
> +
> +    args->postcopy_preempt = true;
> +
> +    if (migrate_postcopy_prepare(&from, &to, args)) {
> +        return;
> +    }
> +    migrate_postcopy_start(from, to);
> +    migrate_postcopy_complete(from, to);
> +}
> +
> +/* @preempt: whether to use postcopy-preempt */
> +static void test_postcopy_recovery(bool preempt)
>  {
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to;
>      g_autofree char *uri = NULL;
>  
>      args->hide_stderr = true;
> +    args->postcopy_preempt = preempt;
>  
>      if (migrate_postcopy_prepare(&from, &to, args)) {
>          return;
> @@ -781,6 +803,16 @@ static void test_postcopy_recovery(void)
>      migrate_postcopy_complete(from, to);
>  }
>  
> +static void test_postcopy_recovery_normal(void)
> +{
> +    test_postcopy_recovery(false);
> +}
> +
> +static void test_postcopy_recovery_preempt(void)
> +{
> +    test_postcopy_recovery(true);
> +}
> +
>  static void test_baddest(void)
>  {
>      MigrateStart *args = migrate_start_new();
> @@ -1458,7 +1490,10 @@ int main(int argc, char **argv)
>      module_call_init(MODULE_INIT_QOM);
>  
>      qtest_add_func("/migration/postcopy/unix", test_postcopy);
> -    qtest_add_func("/migration/postcopy/recovery", test_postcopy_recovery);
> +    qtest_add_func("/migration/postcopy/recovery", test_postcopy_recovery_normal);
> +    qtest_add_func("/migration/postcopy/preempt/unix", test_postcopy_preempt);
> +    qtest_add_func("/migration/postcopy/preempt/recovery",
> +                   test_postcopy_recovery_preempt);
>      qtest_add_func("/migration/bad_dest", test_baddest);
>      qtest_add_func("/migration/precopy/unix", test_precopy_unix);
>      qtest_add_func("/migration/precopy/tcp", test_precopy_tcp);
> -- 
> 2.32.0
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK