[patch 0/5] sched: Miscellaneous RT related tweaks

From: Thomas Gleixner
Date: Tue Sep 28 2021 - 08:24:28 EST


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@xxxxxxxxxxxxx

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(-)