From: Don Zickus on gitlab.com
Merge Request: https://gitlab.com/cki-project/kernel-ark/-/merge_requests/2963
NOTE: Truncated patchset since committer email 'bige...@linutronix.de'
does not match the submitter's GitLab public email address
'dzic...@redhat.com'.
ksoftirqd is statically boosted to the priority level right above the
one of rcu_torture_boost() so that timers, which torture readers rely on,
get a chance to run while rcu_torture_boost() is polling.
However timers processing got split from ksoftirqd into their own kthread
(timersd) that isn't boosted. It has the same SCHED_FIFO low prio as
rcu_torture_boost() and therefore timers can't preempt it and may
starve.
The issue can be triggered in practice on v5.17.1-rt17 using:
./kvm.sh --allcpus --configs TREE04 --duration 10m --kconfig
"CONFIG_EXPERT=y CONFIG_PREEMPT_RT=y"
Fix this with statically boosting timersd just like is done with
ksoftirqd in commit
ea6d962e80b61 ("rcutorture: Judge RCU priority boosting on grace periods,
not callbacks")
Suggested-by: Mel Gorman
Cc: Sebastian Andrzej Siewior
Cc: Thomas Gleixner
Signed-off-by: Frederic Weisbecker
Link: https://lkml.kernel.org/r/20220405010752.1347437-1-frede...@kernel.org
Signed-off-by: Sebastian Andrzej Siewior
---
Documentation/admin-guide/kernel-parameters.txt | 12 +
arch/arm/mm/fault.c |6 +
arch/arm/vfp/vfpmodule.c | 74 +-
arch/arm/Kconfig |6 +-
arch/arm64/Kconfig|1 +
arch/powerpc/include/asm/stackprotector.h |7 +-
arch/powerpc/kernel/traps.c |7 +-
arch/powerpc/kvm/Kconfig |1 +
arch/powerpc/platforms/pseries/Kconfig|1 +
arch/powerpc/platforms/pseries/iommu.c| 31 +-
arch/powerpc/Kconfig |2 +
arch/riscv/include/asm/thread_info.h |2 +
arch/riscv/Kconfig|2 +
arch/x86/include/asm/thread_info.h|6 +-
arch/x86/Kconfig |3 +
drivers/acpi/processor_idle.c |2 +-
drivers/block/zram/zram_drv.c | 37 +
drivers/block/zram/zram_drv.h |3 +
drivers/gpu/drm/i915/display/intel_crtc.c | 15 +-
drivers/gpu/drm/i915/display/intel_vblank.c | 38 +-
drivers/gpu/drm/i915/gt/uc/intel_guc.h|2 +-
drivers/gpu/drm/i915/gt/intel_breadcrumbs.c |5 +-
drivers/gpu/drm/i915/gt/intel_execlists_submission.c | 17 +-
drivers/gpu/drm/i915/Kconfig |1 -
drivers/gpu/drm/i915/i915_request.c |2 -
drivers/gpu/drm/i915/i915_trace.h |6 +-
drivers/gpu/drm/i915/i915_utils.h |2 +-
drivers/tty/serial/8250/8250_core.c | 42 +-
drivers/tty/serial/8250/8250_port.c | 160 +++-
drivers/tty/serial/amba-pl011.c | 12 +-
drivers/tty/serial/omap-serial.c | 12 +-
drivers/tty/tty_io.c |9 +-
fs/proc/consoles.c| 14 +-
include/linux/sched/idle.h|8 +-
include/linux/bottom_half.h |2 +
include/linux/console.h | 127 ++-
include/linux/entry-common.h |2 +-
include/linux/entry-kvm.h |2 +-
include/linux/interrupt.h | 29 +
include/linux/netdevice.h |4 +
include/linux/printk.h| 32 +-
include/linux/sched.h | 13 +-
include/linux/serial_8250.h |6 +
include/linux/serial_core.h | 31 +-
include/linux/thread_info.h | 24 +
include/linux/trace_events.h |8 +-
kernel/entry/common.c |4 +-
kernel/entry/kvm.c|2 +-
kernel/locking/lockdep.c |5 +
kernel/printk/internal.h | 98 +
kernel/printk/nbcon.c | 732 +-
kernel/printk/printk.c| 675 ++--
kernel/printk/printk_ringbuffer.c | 335 +-
kernel/printk/printk_ringbuffer.h
