Re: [PATCH v2 0/8] Fix SCHED_DEADLINE bandwidth accounting during suspend

From: Jon Hunter
Date: Fri Mar 07 2025 - 06:41:09 EST


Hi Juri,

On 06/03/2025 14:10, Juri Lelli wrote:
Hello!

Jon reported [1] a suspend regression on a Tegra board configured to
boot with isolcpus and bisected it to commit 53916d5fd3c0
("sched/deadline: Check bandwidth overflow earlier for hotplug").

Root cause analysis pointed out that we are currently failing to
correctly clear and restore bandwidth accounting on root domains after
changes that initiate from partition_sched_domains(), as it is the case
for suspend operations on that board.

This is v2 [2] of the proposed approach to fix the issue. With respect
to v1, the following implements the approach by:

- 01: filter out DEADLINE special tasks
- 02: preparatory wrappers to be able to grab sched_domains_mutex on
UP (remove !SMP wrappers - Waiman)
- 03: generalize unique visiting of root domains so that we can
re-use the mechanism elsewhere
- 04: the bulk of the approach, clean and rebuild after changes
- 05: clean up a now redundant call
- 06: remove partition_and_rebuild_sched_domains() (Waiman)
- 07: stop exposing partition_sched_domains_locked (Waiman)

Please test and review. The set is also available at


Tested-by: Jon Hunter <jonathanh@xxxxxxxxxx>

Thanks!
Jon

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