On Tue, 25 Jan 2022 17:43:33 +0100 Sebastian Andrzej Siewior <bigeasy@xxxxxxxxxxxxx> wrote: > Hi, > > this series is a follow up to the initial RFC > https://lore.kernel.org/all/20211222114111.2206248-1-bigeasy@xxxxxxxxxxxxx > > and aims to enable MEMCG for PREEMPT_RT instead of disabling it. > > where it has been suggested that I should try again with memcg instead > of simply disabling it. > > Changes since the RFC: > - cgroup.event_control / memory.soft_limit_in_bytes is disabled on > PREEMPT_RT. It is a deprecated v1 feature. Fixing the signal path is > not worth it. > > - The updates to per-CPU counters are usually synchronised by disabling > interrupts. There are a few spots where assumption about disabled > interrupts are not true on PREEMPT_RT and therefore preemption is > disabled. This is okay since the counter are never written from > in_irq() context. > > Patch #2 deals with the counters. > > Patch #3 is a follow up to > https://lkml.kernel.org/r/20211214144412.447035-1-longman@xxxxxxxxxx > > Patch #4 restricts the task_obj usage to !PREEMPTION kernels. Based on > the numbers in > https://lore.kernel.org/all/YdX+INO9gQje6d0S@xxxxxxxxxxxxx This isn't a terribly useful [0/n], sorry. It would be better to have something self-contained which doesn't require that the reader chase down increasingly old links and figure out what changed during successive iterations. > I tested them on CONFIG_PREEMPT_NONE + CONFIG_PREEMPT_RT with the > tools/testing/selftests/cgroup/* tests. It looked good except for the > following (which was also there before the patches): > - test_kmem sometimes complained about: > not ok 2 test_kmem_memcg_deletion Is this a new issue? Does this happen with these patches when CONFIG_PREEMPT_RT=n? > - test_memcontrol complained always about > not ok 3 test_memcg_min > not ok 4 test_memcg_low > and did not finish. Similarly, is this caused by these patches? Is it only triggered under preempt_rt? > - lockdep complains were triggered by test_core and test_freezer (both > had to run): Ditto.
