Fix signalling Wait in regulator.enter #2299
Merged
Conversation
This file contains bidirectional Unicode text that may be interpreted or compiled differently than what appears below. To review, open the file in an editor that reveals hidden Unicode characters.
Learn more about bidirectional Unicode characters
|
Please sign your commits following these rules: $ git clone -b "regulator" git@github.com:dmage/distribution.git somewhere
$ cd somewhere
$ git commit --amend -s --no-edit
$ git push -fAmending updates the existing PR. You DO NOT need to open a new one. |
In some conditions, regulator.exit may not send a signal to blocked regulator.enter. Let's assume we are in the critical section of regulator.exit and r.available is equal to 0. And there are three more gorotines. One goroutine also executes regulator.exit and waits for the lock. Rest run regulator.enter and wait for the signal. We send the signal, and after releasing the lock, there will be lock contention: 1. Wait from regulator.enter 2. Lock from regulator.exit If the winner is Lock from regulator.exit, we will not send another signal to unlock the second Wait. Signed-off-by: Oleg Bulatov <obulatov@redhat.com>
Codecov Report
@@ Coverage Diff @@
## master #2299 +/- ##
===========================================
- Coverage 61.57% 51.53% -10.05%
===========================================
Files 125 125
Lines 11397 11396 -1
===========================================
- Hits 7018 5873 -1145
- Misses 3493 4779 +1286
+ Partials 886 744 -142
Continue to review full report at Codecov.
|
|
LGTM, we've been hit by this in performance testing on GlusterFS. |
|
LGTM |
Sign up for free
to join this conversation on GitHub.
Already have an account?
Sign in to comment
Add this suggestion to a batch that can be applied as a single commit.
This suggestion is invalid because no changes were made to the code.
Suggestions cannot be applied while the pull request is closed.
Suggestions cannot be applied while viewing a subset of changes.
Only one suggestion per line can be applied in a batch.
Add this suggestion to a batch that can be applied as a single commit.
Applying suggestions on deleted lines is not supported.
You must change the existing code in this line in order to create a valid suggestion.
Outdated suggestions cannot be applied.
This suggestion has been applied or marked resolved.
Suggestions cannot be applied from pending reviews.
Suggestions cannot be applied on multi-line comments.
Suggestions cannot be applied while the pull request is queued to merge.
Suggestion cannot be applied right now. Please check back later.
In some conditions, regulator.exit may not send a signal to blocked
regulator.enter.
Let's assume we are in the critical section of regulator.exit and r.available
is equal to 0. And there are three more gorotines. One goroutine also executes
regulator.exit and waits for the lock. Rest run regulator.enter and wait for
the signal.
We send the signal, and after releasing the lock, there will be lock
contention:
If the winner is Lock from regulator.exit, we will not send another signal to
unlock the second Wait.