devicemapper: use atomic.Value for lock-free cache reads#3764
Merged
dims merged 1 commit intogoogle:masterfrom Dec 4, 2025
Merged
devicemapper: use atomic.Value for lock-free cache reads#3764dims merged 1 commit intogoogle:masterfrom
dims merged 1 commit intogoogle:masterfrom
Conversation
The ThinPoolWatcher cache is read frequently by container housekeeping goroutines (via GetUsage) while being updated every 15 seconds by Refresh(). Using atomic.Value allows lock-free reads, eliminating potential contention between the many readers and the single writer. Signed-off-by: Damien Grisonnet <dgrisonn@redhat.com>
Contributor
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I'm not too familiar with the code in this repository, but I noticed the devicemapper code, and wondered if it was actually still used; I know docker / moby dropped support for the devicemapper graph driver; is it still supported (and used) by PodMan? |
Contributor
Author
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That's a good point, I am not familiar enough with the ecosystem to know. @haircommander do you perhaps know if devicemapper driver is still supported? |
Contributor
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Nope not to my understanding. Possibly by kata that was the last remaining user but i doubt it atm |
Contributor
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but kata doesn't use cadvisor, so yeah I don't think we need this |
Contributor
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Thanks! Yeah, so looks like we should be able to start cleaning up some bits. Not the highest priority, but could be a good follow up 👍 |
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The ThinPoolWatcher cache is read frequently by container housekeeping goroutines (via GetUsage) while being updated every 15 seconds by Refresh(). Using atomic.Value allows lock-free reads, eliminating potential contention between the many readers and the single writer.