Bug 211689 - cgroups v1 does not inherit blkio limits
Summary: cgroups v1 does not inherit blkio limits
Status: NEW
Alias: None
Product: Other
Classification: Unclassified
Component: Other (show other bugs)
Hardware: All Linux
: P1 normal
Assignee: other_other
URL:
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Depends on:
Blocks:
 
Reported: 2021-02-10 22:11 UTC by Łukasz Rutkowski
Modified: 2021-02-11 08:26 UTC (History)
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Regression: No
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Description Łukasz Rutkowski 2021-02-10 22:11:11 UTC 
Cgroups does not inherit blkio throttling parameters for sub-cgroups.

According to https://www.kernel.org/doc/html/latest/admin-guide/cgroup-v1/blkio-controller.html only way to force inheritance for blkio limits within cgroups (eg. when Docker container is created inside LXD container) is to use sane_behavior parameter. As I can see (https://github.com/torvalds/linux/blob/291009f656e8eaebbdfd3a8d99f6b190a9ce9deb/kernel/cgroup/cgroup-v1.c#L570) it's now forced to be read only with fixed value "0" (OFF).

From my understanding currently there is now way to force cgroups to apply blkio limits for sub-cgroups which causes sub-cgroups to exceed IOPS or MB/s limits applied to parent cgroup.
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