Changeset c7ceacf in mainline for kernel/generic/src/proc/thread.c

Timestamp:

2024-01-15T14:54:17Z (12 months ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master

Children:

5861b60

Parents:

4760793 (diff), 151c050 (diff)
Note: this is a merge changeset, the changes displayed below correspond to the merge itself.
Use the (diff) links above to see all the changes relative to each parent.

Message:

Merge part of scheduler refactoring changes

A series of changes meant to remove unnecessary spinlock uses and
to improve understandability of the code.

File:

• kernel/generic/src/proc/thread.c (modified) (9 diffs)

kernel/generic/src/proc/thread.c

@@ -82 +82 @@
 };
 
-enum sleep_state {
-        SLEEP_INITIAL,
-        SLEEP_ASLEEP,
-        SLEEP_WOKE,
-};
-
 /** Lock protecting the @c threads ordered dictionary .
  *
@@ -127 +121 @@
         void (*f)(void *) = THREAD->thread_code;
         void *arg = THREAD->thread_arg;
-        THREAD->last_cycle = get_cycle();
 
         /* This is where each thread wakes up after its creation */
@@ -320 +313 @@
 
         current_initialize((current_t *) thread->kstack);
-
-        ipl_t ipl = interrupts_disable();
-        thread->saved_ipl = interrupts_read();
-        interrupts_restore(ipl);
 
         str_cpy(thread->name, THREAD_NAME_BUFLEN, name);
@@ -525 +514 @@
         }
 
-        irq_spinlock_lock(&THREAD->lock, true);
-        THREAD->state = Exiting;
-        irq_spinlock_unlock(&THREAD->lock, true);
-
-        scheduler();
-
-        panic("should never be reached");
+        scheduler_enter(Exiting);
+        unreachable();
 }
 
@@ -579 +563 @@
 }
 
-static void thread_wait_internal(void)
-{
-        assert(THREAD != NULL);
-
-        ipl_t ipl = interrupts_disable();
-
-        if (atomic_load(&haltstate))
-                halt();
-
-        /*
-         * Lock here to prevent a race between entering the scheduler and another
-         * thread rescheduling this thread.
-         */
-        irq_spinlock_lock(&THREAD->lock, false);
-
-        int expected = SLEEP_INITIAL;
-
-        /* Only set SLEEP_ASLEEP in sleep pad if it's still in initial state */
-        if (atomic_compare_exchange_strong_explicit(&THREAD->sleep_state, &expected,
-            SLEEP_ASLEEP, memory_order_acq_rel, memory_order_acquire)) {
-                THREAD->state = Sleeping;
-                scheduler_locked(ipl);
-        } else {
-                assert(expected == SLEEP_WOKE);
-                /* Return immediately. */
-                irq_spinlock_unlock(&THREAD->lock, false);
-                interrupts_restore(ipl);
-        }
-}
-
 static void thread_wait_timeout_callback(void *arg)
 {
@@ -649 +603 @@
         timeout_t timeout;
 
+        /* Extra check to avoid going to scheduler if we don't need to. */
+        if (atomic_load_explicit(&THREAD->sleep_state, memory_order_acquire) !=
+            SLEEP_INITIAL)
+                return THREAD_WAIT_SUCCESS;
+
         if (deadline != DEADLINE_NEVER) {
-                /* Extra check to avoid setting up a deadline if we don't need to. */
-                if (atomic_load_explicit(&THREAD->sleep_state, memory_order_acquire) !=
-                    SLEEP_INITIAL)
-                        return THREAD_WAIT_SUCCESS;
-
                 timeout_initialize(&timeout);
                 timeout_register_deadline(&timeout, deadline,
@@ -660 +614 @@
         }
 
-        thread_wait_internal();
+        scheduler_enter(Sleeping);
 
         if (deadline != DEADLINE_NEVER && !timeout_unregister(&timeout)) {
@@ -674 +628 @@
 
         int state = atomic_exchange_explicit(&thread->sleep_state, SLEEP_WOKE,
-            memory_order_release);
+            memory_order_acq_rel);
 
         if (state == SLEEP_ASLEEP) {
@@ -770 +724 @@
 
         (void) waitq_sleep_timeout(&wq, usec);
+}
+
+/** Allow other threads to run. */
+void thread_yield(void)
+{
+        assert(THREAD != NULL);
+        scheduler_enter(Running);
 }