Francesco Romani has uploaded a new change for review.
Change subject: sampling: fix semaphore misusing
......................................................................
sampling: fix semaphore misusing
We should release the internal _sampling semaphore only
if we acquired it succesfully.
Otherwise, if a previous call was stuck, we violate the
contract of the semaphore.
Change-Id: I9b67cc4efe70b5d2ec8838ace6dfb16648528c46
Backport-To: 3.6
Signed-off-by: Francesco Romani <from...@redhat.com>
---
M vdsm/virt/sampling.py
1 file changed, 4 insertions(+), 3 deletions(-)
git pull ssh://gerrit.ovirt.org:29418/vdsm refs/changes/32/48332/1
diff --git a/vdsm/virt/sampling.py b/vdsm/virt/sampling.py
index 1026eaf..3eaf376 100644
--- a/vdsm/virt/sampling.py
+++ b/vdsm/virt/sampling.py
@@ -492,10 +492,10 @@
def __call__(self):
timestamp = self._stats_cache.clock()
+ acquired = self._sampling.acquire(blocking=False)
# we are deep in the hot path. bool(ExpiringCache)
# *is* costly so we should avoid it if we can.
- fast_path = (
- self._sampling.acquire(blocking=False) and not self._skip_doms)
+ fast_path = acquired and not self._skip_doms
try:
if fast_path:
# This is expected to be the common case.
@@ -516,7 +516,8 @@
else:
self._stats_cache.put(_translate(bulk_stats), timestamp)
finally:
- self._sampling.release()
+ if acquired:
+ self._sampling.release()
def _get_responsive_doms(self):
vms = self._get_vms()
--
To view, visit https://gerrit.ovirt.org/48332
To unsubscribe, visit https://gerrit.ovirt.org/settings
Gerrit-MessageType: newchange
Gerrit-Change-Id: I9b67cc4efe70b5d2ec8838ace6dfb16648528c46
Gerrit-PatchSet: 1
Gerrit-Project: vdsm
Gerrit-Branch: master
Gerrit-Owner: Francesco Romani <from...@redhat.com>
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