Changeset ed7e057 in mainline for kernel/generic/src/proc/scheduler.c

Timestamp:

2024-01-16T15:46:47Z (17 months ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master

Children:

29029ac0, a5b5f17

Parents:

4ed7870

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2024-01-15 20:09:30)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2024-01-16 15:46:47)

Message:

Add functions context_create(), context_replace() and context_swap()

and use them where appropriate, removing context_save() in the process.
Much like in userspace, context_swap() maintains natural control flow
as opposed to context_save()'s return-twice mechanic.

Beyond that, in the future, context_replace() and context_swap()
can be implemented more efficiently than the context_save()/
context_restore() pair. As of now, the original implementation is
retained.

File:

• kernel/generic/src/proc/scheduler.c (modified) (3 diffs)

kernel/generic/src/proc/scheduler.c

@@ -309 +309 @@
 
         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);
-
+        context_replace(scheduler_separated_stack, CPU_LOCAL->stack, STACK_SIZE);
         unreachable();
 }
@@ -452 +446 @@
                 /* Prefer the thread after it's woken up. */
                 THREAD->priority = -1;
-        }
-
-        if (!context_save(&THREAD->saved_context)) {
-                /*
-                 * This is the place where threads leave scheduler();
-                 */
-
-                irq_spinlock_unlock(&THREAD->lock, false);
-                interrupts_restore(ipl);
-                return;
         }
 
@@ -486 +470 @@
          */
         context_t ctx;
-        context_save(&ctx);
-        context_set(&ctx, FADDR(scheduler_separated_stack),
-            (uintptr_t) CPU_LOCAL->stack, STACK_SIZE);
-        context_restore(&ctx);
-
-        /* Not reached */
+        context_create(&ctx, scheduler_separated_stack,
+            CPU_LOCAL->stack, STACK_SIZE);
+
+        /* Switch to scheduler context and store current thread's context. */
+        context_swap(&THREAD->saved_context, &ctx);
+
+        /* Returned from scheduler. */
+
+        irq_spinlock_unlock(&THREAD->lock, false);
+        interrupts_restore(ipl);
 }