Changeset efed95a3 in mainline for kernel/generic/src/proc/scheduler.c

Timestamp:

2024-01-20T17:09:00Z (4 months ago)

Author:

Jiří Zárevúcky <zarevucky.jiri@…>

Branches:

master

Children:

3d84734

Parents:

286da52

git-author:

Jiří Zárevúcky <zarevucky.jiri@…> (2024-01-20 16:12:46)

git-committer:

Jiří Zárevúcky <zarevucky.jiri@…> (2024-01-20 17:09:00)

Message:

Make thread→cpu weakly atomic, to avoid need for thread lock

File:

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

kernel/generic/src/proc/scheduler.c

@@ -311 +311 @@
 
         irq_spinlock_lock(&THREAD->lock, false);
-        assert(THREAD->cpu == CPU);
+        assert(atomic_get_unordered(&THREAD->cpu) == CPU);
 
         THREAD->state = Running;
@@ -387 +387 @@
 
         assert(thread->state == Running);
-        assert(thread->cpu == CPU);
+        assert(atomic_get_unordered(&thread->cpu) == CPU);
 
         int i = (thread->priority < RQ_COUNT - 1) ?
@@ -411 +411 @@
 
         /* Prefer the CPU on which the thread ran last */
-        if (!thread->cpu)
-                thread->cpu = CPU;
-
-        cpu_t *cpu = thread->cpu;
+        cpu_t *cpu = atomic_get_unordered(&thread->cpu);
+
+        if (!cpu) {
+                cpu = CPU;
+                atomic_set_unordered(&thread->cpu, CPU);
+        }
 
         irq_spinlock_unlock(&thread->lock, false);
@@ -656 +658 @@
 
                 thread->stolen = true;
-                thread->cpu = CPU;
+                atomic_set_unordered(&thread->cpu, CPU);
 
                 irq_spinlock_unlock(&thread->lock, false);