Changeset 151c050 in mainline for kernel/generic/src/proc/scheduler.c

Timestamp:

2024-01-15T14:33:03Z (17 months ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master

Children:

c7ceacf

Parents:

8996582

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2023-04-15 16:15:29)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2024-01-15 14:33:03)

Message:

Rethink scheduler entry points

Changes the way scheduler is entered, to eliminate some unnecessary
locking and interrupt disables.

File:

• kernel/generic/src/proc/scheduler.c (modified) (4 diffs)

kernel/generic/src/proc/scheduler.c

@@ -302 +302 @@
 }
 
-void scheduler(void)
-{
-        ipl_t ipl = interrupts_disable();
-
-        if (atomic_load(&haltstate))
-                halt();
-
-        if (THREAD) {
-                irq_spinlock_lock(&THREAD->lock, false);
-        }
-
-        scheduler_locked(ipl);
+void scheduler_run(void)
+{
+        assert(interrupts_disabled());
+        assert(THREAD == NULL);
+        assert(CPU != NULL);
+
+        current_copy(CURRENT, (current_t *) CPU_LOCAL->stack);
+
+        context_t ctx;
+        context_save(&ctx);
+        context_set(&ctx, FADDR(scheduler_separated_stack),
+            (uintptr_t) CPU_LOCAL->stack, STACK_SIZE);
+        context_restore(&ctx);
+
+        unreachable();
 }
 
@@ -431 +434 @@
  *
  */
-void scheduler_locked(ipl_t ipl)
-{
+void scheduler_enter(state_t new_state)
+{
+        ipl_t ipl = interrupts_disable();
+
         assert(CPU != NULL);
-
-        if (THREAD) {
-                /* Update thread kernel accounting */
-                THREAD->kcycles += get_cycle() - THREAD->last_cycle;
-
-                fpu_cleanup();
-
-                if (!context_save(&THREAD->saved_context)) {
-                        /*
-                         * This is the place where threads leave scheduler();
-                         */
-
-                        irq_spinlock_unlock(&THREAD->lock, false);
-                        interrupts_restore(THREAD->saved_ipl);
-
-                        return;
-                }
-
-                /*
-                 * Interrupt priority level of preempted thread is recorded
-                 * here to facilitate scheduler() invocations from
-                 * interrupts_disable()'d code (e.g. waitq_sleep_timeout()).
-                 *
-                 */
-                THREAD->saved_ipl = ipl;
+        assert(THREAD != NULL);
+
+        fpu_cleanup();
+
+        irq_spinlock_lock(&THREAD->lock, false);
+        THREAD->state = new_state;
+
+        /* Update thread kernel accounting */
+        THREAD->kcycles += get_cycle() - THREAD->last_cycle;
+
+        if (!context_save(&THREAD->saved_context)) {
+                /*
+                 * This is the place where threads leave scheduler();
+                 */
+
+                irq_spinlock_unlock(&THREAD->lock, false);
+                interrupts_restore(ipl);
+                return;
         }
 
@@ -504 +502 @@
         assert(interrupts_disabled());
 
+        if (atomic_load(&haltstate))
+                halt();
+
         if (THREAD) {
                 after_thread_ran_arch();
@@ -678 +679 @@
                  *
                  */
-                scheduler();
+                thread_yield();
         } else {
                 /*