[PATCH v2 12/35] sched: separate PREEMPT_DYNAMIC config logic

Ankur Arora
2024-05-28T00:36:24Z

Pull out the PREEMPT_DYNAMIC setup logic to allow other preemption
models to dynamically configure preemption.

Cc: Ingo Molnar <mingo@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Juri Lelli <juri.lelli@redhat.com>
Cc: Vincent Guittot <vincent.guittot@linaro.org>
Signed-off-by: Ankur Arora <ankur.a.arora@oracle.com>
---
kernel/sched/core.c | 165 +++++++++++++++++++++++---------------------
1 file changed, 86 insertions(+), 79 deletions(-)

diff --git a/kernel/sched/core.c b/kernel/sched/core.c
index 0c26b60c1101..349f6257fdcd 100644
--- a/kernel/sched/core.c
+++ b/kernel/sched/core.c
@@ -8713,6 +8713,89 @@ int __cond_resched_rwlock_write(rwlock_t *lock)
}
EXPORT_SYMBOL(__cond_resched_rwlock_write);

+#if defined(CONFIG_PREEMPT_DYNAMIC)
+
+#define PREEMPT_MODE "Dynamic Preempt"
+
+enum {
+ preempt_dynamic_undefined = -1,
+ preempt_dynamic_none,
+ preempt_dynamic_voluntary,
+ preempt_dynamic_full,
+};
+
+int preempt_dynamic_mode = preempt_dynamic_undefined;
+static DEFINE_MUTEX(sched_dynamic_mutex);
+
+int sched_dynamic_mode(const char *str)
+{
+ if (!strcmp(str, "none"))
+ return preempt_dynamic_none;
+
+ if (!strcmp(str, "voluntary"))
+ return preempt_dynamic_voluntary;
+
+ if (!strcmp(str, "full"))
+ return preempt_dynamic_full;
+
+ return -EINVAL;
+}
+
+static void __sched_dynamic_update(int mode);
+void sched_dynamic_update(int mode)
+{
+ mutex_lock(&sched_dynamic_mutex);
+ __sched_dynamic_update(mode);
+ mutex_unlock(&sched_dynamic_mutex);
+}
+
+static void __init preempt_dynamic_init(void)
+{
+ if (preempt_dynamic_mode == preempt_dynamic_undefined) {
+ if (IS_ENABLED(CONFIG_PREEMPT_NONE)) {
+ sched_dynamic_update(preempt_dynamic_none);
+ } else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY)) {
+ sched_dynamic_update(preempt_dynamic_voluntary);
+ } else {
+ /* Default static call setting, nothing to do */
+ WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT));
+ preempt_dynamic_mode = preempt_dynamic_full;
+ pr_info("%s: full\n", PREEMPT_MODE);
+ }
+ }
+}
+
+static int __init setup_preempt_mode(char *str)
+{
+ int mode = sched_dynamic_mode(str);
+ if (mode < 0) {
+ pr_warn("%s: unsupported mode: %s\n", PREEMPT_MODE, str);
+ return 0;
+ }
+
+ sched_dynamic_update(mode);
+ return 1;
+}
+__setup("preempt=", setup_preempt_mode);
+
+#define PREEMPT_MODEL_ACCESSOR(mode) \
+ bool preempt_model_##mode(void) \
+ { \
+ WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \
+ return preempt_dynamic_mode == preempt_dynamic_##mode; \
+ } \
+ EXPORT_SYMBOL_GPL(preempt_model_##mode)
+
+PREEMPT_MODEL_ACCESSOR(none);
+PREEMPT_MODEL_ACCESSOR(voluntary);
+PREEMPT_MODEL_ACCESSOR(full);
+
+#else /* !CONFIG_PREEMPT_DYNAMIC */
+
+static inline void preempt_dynamic_init(void) { }
+
+#endif /* !CONFIG_PREEMPT_DYNAMIC */
+
#ifdef CONFIG_PREEMPT_DYNAMIC

#ifdef CONFIG_GENERIC_ENTRY
@@ -8749,29 +8832,6 @@ EXPORT_SYMBOL(__cond_resched_rwlock_write);
* irqentry_exit_cond_resched <- irqentry_exit_cond_resched
*/

-enum {
- preempt_dynamic_undefined = -1,
- preempt_dynamic_none,
- preempt_dynamic_voluntary,
- preempt_dynamic_full,
-};
-
-int preempt_dynamic_mode = preempt_dynamic_undefined;
-
-int sched_dynamic_mode(const char *str)
-{
- if (!strcmp(str, "none"))
- return preempt_dynamic_none;
-
- if (!strcmp(str, "voluntary"))
- return preempt_dynamic_voluntary;
-
- if (!strcmp(str, "full"))
- return preempt_dynamic_full;
-
- return -EINVAL;
-}
-
#if defined(CONFIG_HAVE_PREEMPT_DYNAMIC_CALL)
#define preempt_dynamic_enable(f) static_call_update(f, f##_dynamic_enabled)
#define preempt_dynamic_disable(f) static_call_update(f, f##_dynamic_disabled)
@@ -8782,7 +8842,6 @@ int sched_dynamic_mode(const char *str)
#error "Unsupported PREEMPT_DYNAMIC mechanism"
#endif

-static DEFINE_MUTEX(sched_dynamic_mutex);
static bool klp_override;

static void __sched_dynamic_update(int mode)
@@ -8807,7 +8866,7 @@ static void __sched_dynamic_update(int mode)
preempt_dynamic_disable(preempt_schedule_notrace);
preempt_dynamic_disable(irqentry_exit_cond_resched);
if (mode != preempt_dynamic_mode)
- pr_info("Dynamic Preempt: none\n");
+ pr_info("%s: none\n", PREEMPT_MODE);
break;

case preempt_dynamic_voluntary:
@@ -8818,7 +8877,7 @@ static void __sched_dynamic_update(int mode)
preempt_dynamic_disable(preempt_schedule_notrace);
preempt_dynamic_disable(irqentry_exit_cond_resched);
if (mode != preempt_dynamic_mode)
- pr_info("Dynamic Preempt: voluntary\n");
+ pr_info("%s: voluntary\n", PREEMPT_MODE);
break;

case preempt_dynamic_full:
@@ -8829,20 +8888,13 @@ static void __sched_dynamic_update(int mode)
preempt_dynamic_enable(preempt_schedule_notrace);
preempt_dynamic_enable(irqentry_exit_cond_resched);
if (mode != preempt_dynamic_mode)
- pr_info("Dynamic Preempt: full\n");
+ pr_info("%s: full\n", PREEMPT_MODE);
break;
}

preempt_dynamic_mode = mode;
}

-void sched_dynamic_update(int mode)
-{
- mutex_lock(&sched_dynamic_mutex);
- __sched_dynamic_update(mode);
- mutex_unlock(&sched_dynamic_mutex);
-}
-
#ifdef CONFIG_HAVE_PREEMPT_DYNAMIC_CALL

static int klp_cond_resched(void)
@@ -8873,51 +8925,6 @@ void sched_dynamic_klp_disable(void)

#endif /* CONFIG_HAVE_PREEMPT_DYNAMIC_CALL */

-static int __init setup_preempt_mode(char *str)
-{
- int mode = sched_dynamic_mode(str);
- if (mode < 0) {
- pr_warn("Dynamic Preempt: unsupported mode: %s\n", str);
- return 0;
- }
-
- sched_dynamic_update(mode);
- return 1;
-}
-__setup("preempt=", setup_preempt_mode);
-
-static void __init preempt_dynamic_init(void)
-{
- if (preempt_dynamic_mode == preempt_dynamic_undefined) {
- if (IS_ENABLED(CONFIG_PREEMPT_NONE)) {
- sched_dynamic_update(preempt_dynamic_none);
- } else if (IS_ENABLED(CONFIG_PREEMPT_VOLUNTARY)) {
- sched_dynamic_update(preempt_dynamic_voluntary);
- } else {
- /* Default static call setting, nothing to do */
- WARN_ON_ONCE(!IS_ENABLED(CONFIG_PREEMPT));
- preempt_dynamic_mode = preempt_dynamic_full;
- pr_info("Dynamic Preempt: full\n");
- }
- }
-}
-
-#define PREEMPT_MODEL_ACCESSOR(mode) \
- bool preempt_model_##mode(void) \
- { \
- WARN_ON_ONCE(preempt_dynamic_mode == preempt_dynamic_undefined); \
- return preempt_dynamic_mode == preempt_dynamic_##mode; \
- } \
- EXPORT_SYMBOL_GPL(preempt_model_##mode)
-
-PREEMPT_MODEL_ACCESSOR(none);
-PREEMPT_MODEL_ACCESSOR(voluntary);
-PREEMPT_MODEL_ACCESSOR(full);
-
-#else /* !CONFIG_PREEMPT_DYNAMIC */
-
-static inline void preempt_dynamic_init(void) { }
-
#endif /* #ifdef CONFIG_PREEMPT_DYNAMIC */

/**
--
2.31.1