Messages in this thread Patch in this message | | | From | Frederic Weisbecker <> | Subject | [PATCH 2/3] preempt/dynamic: Introduce preempt mode accessors | Date | Mon, 14 Mar 2022 14:37:37 +0100 |
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From: Valentin Schneider <valentin.schneider@arm.com>
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.
Introduce a set of helpers to determine the actual preemption mode used by the live kernel.
Suggested-by: Marco Elver <elver@google.com> Signed-off-by: Valentin Schneider <valentin.schneider@arm.com> Signed-off-by: Frederic Weisbecker <frederic@kernel.org> Cc: Uladzislau Rezki <uladzislau.rezki@sony.com> Cc: Joel Fernandes <joel@joelfernandes.org> Cc: Boqun Feng <boqun.feng@gmail.com> Cc: Peter Zijlstra <peterz@infradead.org> Cc: Neeraj Upadhyay <quic_neeraju@quicinc.com> --- include/linux/sched.h | 16 ++++++++++++++++ kernel/sched/core.c | 11 +++++++++++ 2 files changed, 27 insertions(+)
diff --git a/include/linux/sched.h b/include/linux/sched.h index 508b91d57470..d348e886e4d0 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -2096,6 +2096,22 @@ static inline void cond_resched_rcu(void) #endif } +#ifdef CONFIG_PREEMPT_DYNAMIC + +extern bool preempt_mode_none(void); +extern bool preempt_mode_voluntary(void); +extern bool preempt_mode_full(void); + +#else + +#define preempt_mode_none() IS_ENABLED(CONFIG_PREEMPT_NONE) +#define preempt_mode_voluntary() IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY) +#define preempt_mode_full() IS_ENABLED(CONFIG_PREEMPT) + +#endif + +#define preempt_mode_rt() IS_ENABLED(CONFIG_PREEMPT_RT) + /* * Does a critical section need to be broken due to another * task waiting?: (technically does not depend on CONFIG_PREEMPTION, diff --git a/kernel/sched/core.c b/kernel/sched/core.c index 2e4ae00e52d1..6e5c8f0f874a 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -6684,6 +6684,17 @@ static void __init preempt_dynamic_init(void) } } +#define PREEMPT_MODE_ACCESSOR(mode) \ + bool preempt_mode_##mode(void) \ + { \ + WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \ + return preempt_dynamic_mode == preempt_dynamic_##mode; \ + } + +PREEMPT_MODE_ACCESSOR(none) +PREEMPT_MODE_ACCESSOR(voluntary) +PREEMPT_MODE_ACCESSOR(full) + #else /* !CONFIG_PREEMPT_DYNAMIC */ static inline void preempt_dynamic_init(void) { } -- 2.25.1
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