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| author | Valentin Schneider <valentin.schneider@arm.com> | 2021-11-12 21:52:01 +0300 |
|---|---|---|
| committer | Peter Zijlstra <peterz@infradead.org> | 2022-04-05 11:24:42 +0300 |
| commit | cfe43f478b79ba45573ca22d52d0d8823be068fa (patch) | |
| tree | 57e4b23a2770f3889fa8f58ff7296d1bc360b88a /include | |
| parent | 3123109284176b1532874591f7c81f3837bbdc17 (diff) | |
| download | linux-cfe43f478b79ba45573ca22d52d0d8823be068fa.tar.xz | |
preempt/dynamic: Introduce preemption model accessors
CONFIG_PREEMPT{_NONE, _VOLUNTARY} designate either:
o The build-time preemption model when !PREEMPT_DYNAMIC
o The default boot-time preemption model when PREEMPT_DYNAMIC
IOW, using those on PREEMPT_DYNAMIC kernels is meaningless - the actual
model could have been set to something else by the "preempt=foo" cmdline
parameter. Same problem applies to CONFIG_PREEMPTION.
Introduce a set of helpers to determine the actual preemption model used by
the live kernel.
Suggested-by: Marco Elver <elver@google.com>
Signed-off-by: Valentin Schneider <valentin.schneider@arm.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
Reviewed-by: Marco Elver <elver@google.com>
Acked-by: Frederic Weisbecker <frederic@kernel.org>
Link: https://lore.kernel.org/r/20211112185203.280040-3-valentin.schneider@arm.com
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/sched.h | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index d5e3c00b74e1..67f06f72c50e 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2117,6 +2117,47 @@ static inline void cond_resched_rcu(void) #endif } +#ifdef CONFIG_PREEMPT_DYNAMIC + +extern bool preempt_model_none(void); +extern bool preempt_model_voluntary(void); +extern bool preempt_model_full(void); + +#else + +static inline bool preempt_model_none(void) +{ + return IS_ENABLED(CONFIG_PREEMPT_NONE); +} +static inline bool preempt_model_voluntary(void) +{ + return IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY); +} +static inline bool preempt_model_full(void) +{ + return IS_ENABLED(CONFIG_PREEMPT); +} + +#endif + +static inline bool preempt_model_rt(void) +{ + return IS_ENABLED(CONFIG_PREEMPT_RT); +} + +/* + * Does the preemption model allow non-cooperative preemption? + * + * For !CONFIG_PREEMPT_DYNAMIC kernels this is an exact match with + * CONFIG_PREEMPTION; for CONFIG_PREEMPT_DYNAMIC this doesn't work as the + * kernel is *built* with CONFIG_PREEMPTION=y but may run with e.g. the + * PREEMPT_NONE model. + */ +static inline bool preempt_model_preemptible(void) +{ + return preempt_model_full() || preempt_model_rt(); +} + /* * Does a critical section need to be broken due to another * task waiting?: (technically does not depend on CONFIG_PREEMPTION, |