Changeset dbe9ff0 in mainline

Timestamp:

2005-09-01T08:53:06Z (19 years ago)

Author:

Jakub Jermar <jakub@…>

Branches:

lfn, master, serial, ticket/834-toolchain-update, topic/msim-upgrade, topic/simplify-dev-export

Children:

f944715

Parents:

75d5721

Message:

Preemption work.
Define PREEMPTION_DISABLED macro.
This macro determines the level of preemptivity (0 = preemption enabled, THE→preemption_disabled = no preemption inside spinlock, 1 = preemption disabled).
Reformulate preemption code in clock.c to consider PREEMPTION_DISABLED.

Files:

• include/arch.h (modified) (1 diff)
• src/time/clock.c (modified) (2 diffs)

include/arch.h

@@ -40 +40 @@
 #include <proc/task.h>
 
-#define CPU             THE->cpu
-#define THREAD          THE->thread
-#define TASK            THE->task
+#define CPU                     THE->cpu
+#define THREAD                  THE->thread
+#define TASK                    THE->task
+#define PREEMPTION_DISABLED     THE->preemption_disabled
 
 #ifndef early_mapping

src/time/clock.c

@@ -85 +85 @@
 
         if (THREAD) {
+                __u64 ticks;
+                
                 spinlock_lock(&CPU->lock);
                 CPU->needs_relink++;
@@ -90 +92 @@
         
                 spinlock_lock(&THREAD->lock);
-                if (!THREAD->ticks--) {
-                        spinlock_unlock(&THREAD->lock);
+                if (ticks = THREAD->ticks)
+                        THREAD->ticks--;
+                spinlock_unlock(&THREAD->lock);
+                
+                if (!ticks && !PREEMPTION_DISABLED) {
                         scheduler();
-                }
-                else {
-                        spinlock_unlock(&THREAD->lock);
                 }
         }