An upstream bug has been opened on the matter for quite some time now [0].
I can reproduce easily on our production compute node instance, which are trusty host with xenial hwe kernels (4.15.0-101-generic).
However due to heavy backport and such, doing real tracing is a bit hard there.
I was able to reproduce the behavior on a hwe-bionic kernel as well.
Since most of our critical deployments use bcache, I think this is a kinda nasty bug to have.
Reproducing the issue is relatively easy with the script provided in the bug [1].
The script used to capture the stats is this one [2].
Hello,
An upstream bug has been opened on the matter for quite some time now [0]. 101-generic) .
I can reproduce easily on our production compute node instance, which are trusty host with xenial hwe kernels (4.15.0-
However due to heavy backport and such, doing real tracing is a bit hard there.
I was able to reproduce the behavior on a hwe-bionic kernel as well.
Since most of our critical deployments use bcache, I think this is a kinda nasty bug to have.
Reproducing the issue is relatively easy with the script provided in the bug [1].
The script used to capture the stats is this one [2].
[0]: https:/ /bugzilla. kernel. org/show_ bug.cgi? id=206767 /pastebin. ubuntu. com/p/YnnvvSRhX K/ /pastebin. ubuntu. com/p/XfVpzg32s N/
[1]: https:/
[2]: https:/