iotests/030: Unthrottle parallel jobs in reverse

See the comment for why this is necessary.

Signed-off-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20211111120829.81329-11-hreitz@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>
Message-Id: <20211115145409.176785-11-kwolf@redhat.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
This commit is contained in:
Hanna Reitz 2021-11-15 15:54:06 +01:00
parent b0a9f6fed3
commit 16e29cc050
1 changed files with 10 additions and 1 deletions

View File

@ -251,7 +251,16 @@ class TestParallelOps(iotests.QMPTestCase):
speed=1024)
self.assert_qmp(result, 'return', {})
for job in pending_jobs:
# Do this in reverse: After unthrottling them, some jobs may finish
# before we have unthrottled all of them. This will drain their
# subgraph, and this will make jobs above them advance (despite those
# jobs on top being throttled). In the worst case, all jobs below the
# top one are finished before we can unthrottle it, and this makes it
# advance so far that it completes before we can unthrottle it - which
# results in an error.
# Starting from the top (i.e. in reverse) does not have this problem:
# When a job finishes, the ones below it are not advanced.
for job in reversed(pending_jobs):
result = self.vm.qmp('block-job-set-speed', device=job, speed=0)
self.assert_qmp(result, 'return', {})