Re: [Qemu-devel] [PATCH for-3.0 0/9] migration: postcopy recovery unit test, bug fixes

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

* Peter Xu (peterx@redhat.com) wrote:
> On Fri, Jul 06, 2018 at 11:56:59AM +0100, Dr. David Alan Gilbert wrote:
> > * Dr. David Alan Gilbert (dgilbert@redhat.com) wrote:
> > > * Peter Xu (peterx@redhat.com) wrote:
> > > > Based-on: <20180627132246.5576-1-peterx@redhat.com>
> > > > 
> > > > Based on the series to unbreak postcopy:
> > > >   Subject: [PATCH v3 0/4] migation: unbreak postcopy recovery
> > > >   Message-Id: <20180627132246.5576-1-peterx@redhat.com>
> > > > 
> > > > This series introduce a new postcopy recovery test.  The new test
> > > > actually helped me to identify two bugs there so fix them as well
> > > > before 3.0 release.
> > > > 
> > > > Patch 1: a trivial cleanup for existing postcopy ram load, which I
> > > >          found a bit confusing during debugging the problem.
> > > > 
> > > > Patch 2-3: two bug fixes that address different issues.  Please see
> > > >            the commit log for more information.
> > > > 
> > > > Patch 4-9: add the postcopy recovery unit test.
> > > > 
> > > > Please review.  Thanks,
> > > 
> > > Queued
> > 
> > Hi Peter,
> >   There's a problem in there somewhere;  I'm getting
> > an intermittent failure of the test if I run a make check -j 8    on my
> > laptop.  Just running two copies of tests/migration-test in parallel
> > sometimes triggers it (but not if I turn on QTEST_LOG!).
> > But it's always failing with:
> > 
> >   ERROR:/home/dgilbert/git/migpull/tests/migration-test.c:373:migrate_recover: assertion failed: (qdict_haskey(rsp, "return"))
> 
> Hmm, so this should be a race.  I suspect it's because destination VM
> hasn't reached the correct state when sending the recovery command.
> 
> Could you help to try these two tiny patches to see whether it can fix
> the problem?

Yes, this seems to work; even running 6 in parallel.

Dave

> ================
> 
> commit d875ea1a98932174e3fa202859b65df26def174d
> Author: Peter Xu <peterx@redhat.com>
> Date:   Tue Jul 10 11:17:24 2018 +0800
> 
>     migration: show pause/recover state on dst host
> 
>     These two states will be missing when doing "query-migrate" on
>     destination VM.  Add these states so that we can get the query results
>     as expected.
> 
>     Signed-off-by: Peter Xu <peterx@redhat.com>
> 
> diff --git a/migration/migration.c b/migration/migration.c
> index 0404c53215..8d56d56930 100644
> --- a/migration/migration.c
> +++ b/migration/migration.c
> @@ -911,6 +911,8 @@ static void fill_destination_migration_info(MigrationInfo *info)
>      case MIGRATION_STATUS_CANCELLED:
>      case MIGRATION_STATUS_ACTIVE:
>      case MIGRATION_STATUS_POSTCOPY_ACTIVE:
> +    case MIGRATION_STATUS_POSTCOPY_PAUSED:
> +    case MIGRATION_STATUS_POSTCOPY_RECOVER:
>      case MIGRATION_STATUS_FAILED:
>      case MIGRATION_STATUS_COLO:
>          info->has_status = true;
> 
> ================
> 
> commit 9fa7fc773961cd0ea0b5f70a166def0d8aebf464
> Author: Peter Xu <peterx@redhat.com>
> Date:   Tue Jul 10 11:18:48 2018 +0800
> 
>     tests: don't send recovery cmd until dst pauses
> 
>     Signed-off-by: Peter Xu <peterx@redhat.com>
> 
> diff --git a/tests/migration-test.c b/tests/migration-test.c
> index 96e69dab99..45558446f1 100644
> --- a/tests/migration-test.c
> +++ b/tests/migration-test.c
> @@ -646,6 +646,13 @@ static void test_postcopy_recovery(void)
>       */
>      migrate_pause(from);
> 
> +    /*
> +     * Wait for destination side to reach postcopy-paused state.  The
> +     * migrate-recover command can only succeed if destination machine
> +     * is in the paused state
> +     */
> +    wait_for_migration_status(to, "postcopy-paused");
> +
>      /*
>       * Create a new socket to emulate a new channel that is different
>       * from the broken migration channel; tell the destination to
> 
> ================
> 
> Thanks!
> 
> -- 
> Peter Xu
--
Dr. David Alan Gilbert / dgilbert@redhat.com / Manchester, UK