Re: [PATCH 2/2] tests: migration-test: Add dirty ring test

[Dr. David Alan Gilbert]

* Peter Xu (peterx@redhat.com) wrote:
> Add dirty ring test if kernel supports it.  Add the dirty ring parameter on
> source should be mostly enough, but let's change the dest too to make them
> match always.
> 
> Signed-off-by: Peter Xu <peterx@redhat.com>
> ---
>  tests/qtest/migration-test.c | 51 +++++++++++++++++++++++++++++++++---
>  1 file changed, 48 insertions(+), 3 deletions(-)
> 
> diff --git a/tests/qtest/migration-test.c b/tests/qtest/migration-test.c
> index d9225f58d4d..cc6e396d1a2 100644
> --- a/tests/qtest/migration-test.c
> +++ b/tests/qtest/migration-test.c
> @@ -12,6 +12,7 @@
>  
>  #include "qemu/osdep.h"
>  
> +#include <linux/kvm.h>

Does that get you the system headers, which may or may not have
KVM_CAP_DIRTY_LOG_RING if you're on an old host, or does it get you
qemu's linux-headers which definitely does?

What happens on a BSD or the like?

Dave

>  #include "libqos/libqtest.h"
>  #include "qapi/error.h"
>  #include "qapi/qmp/qdict.h"
> @@ -467,6 +468,8 @@ typedef struct {
>      bool use_shmem;
>      /* only launch the target process */
>      bool only_target;
> +    /* Use dirty ring if true; dirty logging otherwise */
> +    bool use_dirty_ring;
>      char *opts_source;
>      char *opts_target;
>  } MigrateStart;
> @@ -573,11 +576,13 @@ static int test_migrate_start(QTestState **from, 
> QTestState **to,
>          shmem_opts = g_strdup("");
>      }
>  
> -    cmd_source = g_strdup_printf("-accel kvm -accel tcg%s%s "
> +    cmd_source = g_strdup_printf("-accel kvm%s -accel tcg%s%s "
>                                   "-name source,debug-threads=on "
>                                   "-m %s "
>                                   "-serial file:%s/src_serial "
>                                   "%s %s %s %s",
> +                                 args->use_dirty_ring ?
> +                                 ",dirty-ring-size=4096" : "",
>                                   machine_opts ? " -machine " : "",
>                                   machine_opts ? machine_opts : "",
>                                   memory_size, tmpfs,
> @@ -587,12 +592,14 @@ static int test_migrate_start(QTestState **from, 
> QTestState **to,
>          *from = qtest_init(cmd_source);
>      }
>  
> -    cmd_target = g_strdup_printf("-accel kvm -accel tcg%s%s "
> +    cmd_target = g_strdup_printf("-accel kvm%s -accel tcg%s%s "
>                                   "-name target,debug-threads=on "
>                                   "-m %s "
>                                   "-serial file:%s/dest_serial "
>                                   "-incoming %s "
>                                   "%s %s %s %s",
> +                                 args->use_dirty_ring ?
> +                                 ",dirty-ring-size=4096" : "",
>                                   machine_opts ? " -machine " : "",
>                                   machine_opts ? machine_opts : "",
>                                   memory_size, tmpfs, uri,
> @@ -785,12 +792,14 @@ static void test_baddest(void)
>      test_migrate_end(from, to, false);
>  }
>  
> -static void test_precopy_unix(void)
> +static void test_precopy_unix_common(bool dirty_ring)
>  {
>      g_autofree char *uri = g_strdup_printf("unix:%s/migsocket", tmpfs);
>      MigrateStart *args = migrate_start_new();
>      QTestState *from, *to;
>  
> +    args->use_dirty_ring = dirty_ring;
> +
>      if (test_migrate_start(&from, &to, uri, args)) {
>          return;
>      }
> @@ -825,6 +834,18 @@ static void test_precopy_unix(void)
>      test_migrate_end(from, to, true);
>  }
>  
> +static void test_precopy_unix(void)
> +{
> +    /* Using default dirty logging */
> +    test_precopy_unix_common(false);
> +}
> +
> +static void test_precopy_unix_dirty_ring(void)
> +{
> +    /* Using dirty ring tracking */
> +    test_precopy_unix_common(true);
> +}
> +
>  #if 0
>  /* Currently upset on aarch64 TCG */
>  static void test_ignore_shared(void)
> @@ -1369,6 +1390,25 @@ static void test_multifd_tcp_cancel(void)
>      test_migrate_end(from, to2, true);
>  }
>  
> +static bool kvm_dirty_ring_supported(void)
> +{
> +    int ret, kvm_fd = open("/dev/kvm", O_RDONLY);
> +
> +    if (kvm_fd < 0) {
> +        return false;
> +    }
> +
> +    ret = ioctl(kvm_fd, KVM_CHECK_EXTENSION, KVM_CAP_DIRTY_LOG_RING);
> +    close(kvm_fd);
> +
> +    /* We test with 4096 slots */
> +    if (ret < 4096) {
> +        return false;
> +    }
> +
> +    return true;
> +}
> +
>  int main(int argc, char **argv)
>  {
>      char template[] = "/tmp/migration-test-XXXXXX";
> @@ -1438,6 +1478,11 @@ int main(int argc, char **argv)
>      qtest_add_func("/migration/multifd/tcp/zstd", test_multifd_tcp_zstd);
>  #endif
>  
> +    if (kvm_dirty_ring_supported()) {
> +        qtest_add_func("/migration/dirty_ring",
> +                       test_precopy_unix_dirty_ring);
> +    }
> +
>      ret = g_test_run();
>  
>      g_assert_cmpint(ret, ==, 0);
> -- 
> 2.31.1
> 
-- 
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK