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* [patch 0/5] sched: Miscellaneous RT related tweaks
@ 2021-09-28 12:24 Thomas Gleixner
  2021-09-28 12:24 ` [patch 1/5] sched: Limit the number of task migrations per batch on RT Thomas Gleixner
                   ` (4 more replies)
  0 siblings, 5 replies; 22+ messages in thread
From: Thomas Gleixner @ 2021-09-28 12:24 UTC (permalink / raw)
  To: LKML
  Cc: Peter Zijlstra, Ingo Molnar, Masami Hiramatsu, Sebastian Andrzej Siewior

RT enabled kernels have a few issues with the inner workings of the
scheduler:

   - The remote TTWU_QUEUE mechanism leads to 5x larger maximum latencies

   - The batched migration limit of 32 tasks causes large latencies

   - The cleanup of kprobes, vmapped stacks of dead tasks and mmdrop() are
     latency sources and eventually calling into code pathes which take
     regular spinlocks from within the scheduler core which has preemption
     disabled.

The following series cleans this up. It is also available from git:

    git://git.kernel.org/pub/scm/linux/kernel/git/tglx/devel.git sched

applied on top of the previous might_sleep() cleanups:

    https://lore.kernel.org/r/20210923164145.466686140@linutronix.de

Thanks,

	tglx
---
 include/linux/mm_types.h |    4 ++++
 include/linux/sched/mm.h |   20 ++++++++++++++++++++
 kernel/exit.c            |    7 +++++++
 kernel/fork.c            |   18 +++++++++++++++++-
 kernel/kprobes.c         |    8 ++++----
 kernel/sched/core.c      |   16 +++++++++-------
 kernel/sched/features.h  |    5 +++++
 7 files changed, 66 insertions(+), 12 deletions(-)



^ permalink raw reply	[flat|nested] 22+ messages in thread

end of thread, other threads:[~2021-10-05 14:12 UTC | newest]

Thread overview: 22+ messages (download: mbox.gz / follow: Atom feed)
-- links below jump to the message on this page --
2021-09-28 12:24 [patch 0/5] sched: Miscellaneous RT related tweaks Thomas Gleixner
2021-09-28 12:24 ` [patch 1/5] sched: Limit the number of task migrations per batch on RT Thomas Gleixner
2021-10-01 15:05   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2021-10-05 14:11   ` tip-bot2 for Thomas Gleixner
2021-09-28 12:24 ` [patch 2/5] sched: Disable TTWU_QUEUE " Thomas Gleixner
2021-10-01 15:05   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2021-10-05 14:11   ` tip-bot2 for Thomas Gleixner
2021-09-28 12:24 ` [patch 3/5] sched: Move kprobes cleanup out of finish_task_switch() Thomas Gleixner
2021-10-01 15:05   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2021-10-05 14:11   ` tip-bot2 for Thomas Gleixner
2021-09-28 12:24 ` [patch 4/5] sched: Delay task stack freeing on RT Thomas Gleixner
2021-09-29 11:54   ` Peter Zijlstra
2021-10-01 16:12     ` Andy Lutomirski
2021-10-01 17:24       ` Thomas Gleixner
2021-10-01 18:48         ` Andy Lutomirski
2021-10-01 19:02           ` Andy Lutomirski
2021-10-01 20:54             ` Thomas Gleixner
2021-09-28 12:24 ` [patch 5/5] sched: Move mmdrop to RCU " Thomas Gleixner
2021-09-29 12:02   ` Peter Zijlstra
2021-09-29 13:05     ` Thomas Gleixner
2021-10-01 15:05   ` [tip: sched/core] " tip-bot2 for Thomas Gleixner
2021-10-05 14:11   ` tip-bot2 for Thomas Gleixner

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