Changeset 057e77f in mainline for kernel/generic/src

Timestamp:

2012-07-16T15:31:56Z (13 years ago)

Author:

Adam Hraska <adam.hraska+hos@…>

Branches:

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

Children:

0cf813d

Parents:

0594c7ea

Message:

preemption_disable: Removed failed attempt at rescheduling once preemption is enabled (and needed). Once again, preemption_enable() never reschedules.

Location:

kernel/generic/src

Files:

• preempt/preemption.c (modified) (1 diff)
• time/clock.c (modified) (1 diff)

kernel/generic/src/preempt/preemption.c

@@ -37 +37 @@
 
 #include <preemption.h>
-#include <proc/scheduler.h>
 
-
-/** Determines if we are executing an exception/interrupt handler. */
-static bool in_exc_handler(void)
-{
-        /* Err on the safe side until all exception processing code is audited. */
-        return true;
-}
-
-/** Preemption was enabled. Calls scheduler(). */
-void preemption_enabled_scheduler(void)
-{
-        ASSERT(PREEMPTION_ENABLED);
-        ASSERT(PREEMPTION_NEEDED);
-        
-        /* 
-         * Avoid a race between a thread about to invoke the scheduler() 
-         * after checking THREAD->need_resched and an interrupt that
-         * occurs right after the check.
-         * 
-         * Also ensures that code that relies on disabled interrupts
-         * to suppress preemption continues to work.
-         */
-        if (!interrupts_disabled() && !in_exc_handler()) {
-                preemption_clear_needed();
-                /* We may be preempted here, so we'll scheduler() again. Too bad. */
-                scheduler();
-        } 
-}
-
-/** Sets a flag to reschedule the next time preemption is enabled. */
-void preemption_set_needed(void)
-{
-        /* No need to disable interrupts. */
-        THE->preemption |= PREEMPTION_NEEDED_FLAG;
-}
-
-/** Instructs not to reschedule immediately when preemption is enabled. */
-void preemption_clear_needed(void)
-{
-        /* No need to disable interrupts. */
-        THE->preemption &= ~PREEMPTION_NEEDED_FLAG;
-}
 
 /** @}

kernel/generic/src/time/clock.c

@@ -212 +212 @@
                 irq_spinlock_unlock(&THREAD->lock, false);
                 
-                if (ticks == 0) {
-                        if (PREEMPTION_ENABLED) {
-                                scheduler();
+                if (ticks == 0 && PREEMPTION_ENABLED) {
+                        scheduler();
 #ifdef CONFIG_UDEBUG
-                                /*
-                                * Give udebug chance to stop the thread
-                                * before it begins executing userspace code.
-                                */
-                                istate_t *istate = THREAD->udebug.uspace_state;
-                                if ((istate) && (istate_from_uspace(istate)))
-                                        udebug_before_thread_runs();
+                        /*
+                         * Give udebug chance to stop the thread
+                         * before it begins executing userspace code.
+                         */
+                        istate_t *istate = THREAD->udebug.uspace_state;
+                        if ((istate) && (istate_from_uspace(istate)))
+                                udebug_before_thread_runs();
 #endif
-                        } else {
-                                preemption_set_needed();
-                        }
                 }
         }