Messages in this thread Patch in this message | | | From | David Vernet <> | Subject | [PATCH v3 4/7] sched: Enable sched_feat callbacks on enable/disable | Date | Wed, 9 Aug 2023 17:12:15 -0500 |
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When a scheduler feature is enabled or disabled, the sched_feat_enable() and sched_feat_disable() functions are invoked respectively for that feature. For features that don't require resetting any state, this works fine. However, there will be an upcoming feature called shared_runq which needs to drain all tasks from a set of global shared runqueues in order to avoid stale tasks from staying in the queues after the feature has been disabled.
This patch therefore defines a new SCHED_FEAT_CALLBACK macro which allows scheduler features to specify a callback that should be invoked when a feature is enabled or disabled respectively. The SCHED_FEAT macro assumes a NULL callback.
Signed-off-by: David Vernet <void@manifault.com> --- kernel/sched/core.c | 4 ++-- kernel/sched/debug.c | 18 ++++++++++++++---- kernel/sched/sched.h | 16 ++++++++++------ 3 files changed, 26 insertions(+), 12 deletions(-)
diff --git a/kernel/sched/core.c b/kernel/sched/core.c index dd6412a49263..385c565da87f 100644 --- a/kernel/sched/core.c +++ b/kernel/sched/core.c @@ -124,12 +124,12 @@ DEFINE_PER_CPU_SHARED_ALIGNED(struct rq, runqueues); * sysctl_sched_features, defined in sched.h, to allow constants propagation * at compile time and compiler optimization based on features default. */ -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ (1UL << __SCHED_FEAT_##name) * enabled | const_debug unsigned int sysctl_sched_features = #include "features.h" 0; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK /* * Print a warning if need_resched is set for the given duration (if diff --git a/kernel/sched/debug.c b/kernel/sched/debug.c index aeeba46a096b..803dff75c56f 100644 --- a/kernel/sched/debug.c +++ b/kernel/sched/debug.c @@ -44,14 +44,14 @@ static unsigned long nsec_low(unsigned long long nsec) #define SPLIT_NS(x) nsec_high(x), nsec_low(x) -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ #name , static const char * const sched_feat_names[] = { #include "features.h" }; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK static int sched_feat_show(struct seq_file *m, void *v) { @@ -72,22 +72,32 @@ static int sched_feat_show(struct seq_file *m, void *v) #define jump_label_key__true STATIC_KEY_INIT_TRUE #define jump_label_key__false STATIC_KEY_INIT_FALSE -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ jump_label_key__##enabled , struct static_key sched_feat_keys[__SCHED_FEAT_NR] = { #include "features.h" }; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK + +#define SCHED_FEAT_CALLBACK(name, enabled, cb) cb, +static const sched_feat_change_f sched_feat_cbs[__SCHED_FEAT_NR] = { +#include "features.h" +}; +#undef SCHED_FEAT_CALLBACK static void sched_feat_disable(int i) { + if (sched_feat_cbs[i]) + sched_feat_cbs[i](false); static_key_disable_cpuslocked(&sched_feat_keys[i]); } static void sched_feat_enable(int i) { + if (sched_feat_cbs[i]) + sched_feat_cbs[i](true); static_key_enable_cpuslocked(&sched_feat_keys[i]); } #else diff --git a/kernel/sched/sched.h b/kernel/sched/sched.h index 88cca7cc00cf..2631da3c8a4d 100644 --- a/kernel/sched/sched.h +++ b/kernel/sched/sched.h @@ -2065,6 +2065,8 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) #endif } +#define SCHED_FEAT(name, enabled) SCHED_FEAT_CALLBACK(name, enabled, NULL) + /* * Tunables that become constants when CONFIG_SCHED_DEBUG is off: */ @@ -2074,7 +2076,7 @@ static inline void __set_task_cpu(struct task_struct *p, unsigned int cpu) # define const_debug const #endif -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ __SCHED_FEAT_##name , enum { @@ -2082,7 +2084,7 @@ enum { __SCHED_FEAT_NR, }; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK #ifdef CONFIG_SCHED_DEBUG @@ -2093,14 +2095,14 @@ enum { extern const_debug unsigned int sysctl_sched_features; #ifdef CONFIG_JUMP_LABEL -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ static __always_inline bool static_branch_##name(struct static_key *key) \ { \ return static_key_##enabled(key); \ } #include "features.h" -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; #define sched_feat(x) (static_branch_##x(&sched_feat_keys[__SCHED_FEAT_##x])) @@ -2118,17 +2120,19 @@ extern struct static_key sched_feat_keys[__SCHED_FEAT_NR]; * constants propagation at compile time and compiler optimization based on * features default. */ -#define SCHED_FEAT(name, enabled) \ +#define SCHED_FEAT_CALLBACK(name, enabled, cb) \ (1UL << __SCHED_FEAT_##name) * enabled | static const_debug __maybe_unused unsigned int sysctl_sched_features = #include "features.h" 0; -#undef SCHED_FEAT +#undef SCHED_FEAT_CALLBACK #define sched_feat(x) !!(sysctl_sched_features & (1UL << __SCHED_FEAT_##x)) #endif /* SCHED_DEBUG */ +typedef void (*sched_feat_change_f)(bool enabling); + extern struct static_key_false sched_numa_balancing; extern struct static_key_false sched_schedstats; -- 2.41.0
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