diff options
| author | Linus Torvalds <torvalds@linux-foundation.org> | 2022-10-10 20:03:24 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2022-10-10 20:03:24 +0300 |
| commit | 7f6dcffb44ad246e3211c6aeaba8a625e2766836 (patch) | |
| tree | eb433bcc3b419c32d7fb82111c006887bae77f3c /lib | |
| parent | 65f109e19976a833c18820e3950c8f2bb8bd19b4 (diff) | |
| parent | 44b0c2957adc62b86fcd51adeaf8e993171bc319 (diff) | |
Merge tag 'sched-rt-2022-10-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull preempt RT updates from Thomas Gleixner:
"Introduce preempt_[dis|enable_nested() and use it to clean up various
places which have open coded PREEMPT_RT conditionals.
On PREEMPT_RT enabled kernels, spinlocks and rwlocks are neither
disabling preemption nor interrupts. Though there are a few places
which depend on the implicit preemption/interrupt disable of those
locks, e.g. seqcount write sections, per CPU statistics updates etc.
PREEMPT_RT added open coded CONFIG_PREEMPT_RT conditionals to
disable/enable preemption in the related code parts all over the
place. That's hard to read and does not really explain why this is
necessary.
Linus suggested to use helper functions (preempt_disable_nested() and
preempt_enable_nested()) and use those in the affected places. On !RT
enabled kernels these functions are NOPs, but contain a lockdep assert
to validate that preemption is actually disabled to catch call sites
which do not have preemption disabled.
Clean up the affected code paths in mm, dentry and lib"
* tag 'sched-rt-2022-10-05' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
u64_stats: Streamline the implementation
flex_proportions: Disable preemption entering the write section.
mm/compaction: Get rid of RT ifdeffery
mm/memcontrol: Replace the PREEMPT_RT conditionals
mm/debug: Provide VM_WARN_ON_IRQS_ENABLED()
mm/vmstat: Use preempt_[dis|en]able_nested()
dentry: Use preempt_[dis|en]able_nested()
preempt: Provide preempt_[dis|en]able_nested()
Diffstat (limited to 'lib')
| -rw-r--r-- | lib/Kconfig.debug | 3 | ||||
| -rw-r--r-- | lib/flex_proportions.c | 2 |
2 files changed, 5 insertions, 0 deletions
diff --git a/lib/Kconfig.debug b/lib/Kconfig.debug index 405c8634d028..3761118d1879 100644 --- a/lib/Kconfig.debug +++ b/lib/Kconfig.debug @@ -805,6 +805,9 @@ config ARCH_HAS_DEBUG_VM_PGTABLE An architecture should select this when it can successfully build and run DEBUG_VM_PGTABLE. +config DEBUG_VM_IRQSOFF + def_bool DEBUG_VM && !PREEMPT_RT + config DEBUG_VM bool "Debug VM" depends on DEBUG_KERNEL diff --git a/lib/flex_proportions.c b/lib/flex_proportions.c index 05cccbcf1661..83332fefa6f4 100644 --- a/lib/flex_proportions.c +++ b/lib/flex_proportions.c @@ -70,6 +70,7 @@ bool fprop_new_period(struct fprop_global *p, int periods) */ if (events <= 1) return false; + preempt_disable_nested(); write_seqcount_begin(&p->sequence); if (periods < 64) events -= events >> periods; @@ -77,6 +78,7 @@ bool fprop_new_period(struct fprop_global *p, int periods) percpu_counter_add(&p->events, -events); p->period += periods; write_seqcount_end(&p->sequence); + preempt_enable_nested(); return true; } |