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minor optimization on single core systems

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This commit is contained in:
Stefan Lankes 2011-08-02 07:07:16 +02:00
parent 5ffa35351c
commit 744abc36c8
1 changed files with 12 additions and 2 deletions
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14
kernel/tasks.c
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@ -52,7 +52,9 @@ static task_t task_table[MAX_TASKS] = { \
static spinlock_irqsave_t table_lock = SPINLOCK_IRQSAVE_INIT;
DEFINE_PER_CORE(task_t*, current_task, task_table+0);
#if MAX_CORES > 1
DEFINE_PER_CORE_STATIC(task_t*, old_task, NULL);
#endif
/** @brief helper function for the assembly code to determine the current task
* @return Pointer to the task_t structure of current task
@ -177,6 +179,7 @@ void NORETURN abort(void) {
*/
inline static void task_switch_finished(void)
{
#if MAX_CORES > 1
uint32_t flags = irq_nested_disable();
// do we already reset the TASK_SWITCH_IN_PROGRESS bit?
@ -187,6 +190,7 @@ inline static void task_switch_finished(void)
}
irq_nested_enable(flags);
#endif
}
/** @brief Create a task with a specific entry point
@ -839,10 +843,14 @@ void scheduler(void)
if ((task_table[new_id].status == TASK_READY) && !(task_table[new_id].flags & TASK_SWITCH_IN_PROGESS)) {
if (curr_task->status == TASK_RUNNING) {
curr_task->status = TASK_READY;
#if MAX_CORES > 1
curr_task->flags |= TASK_SWITCH_IN_PROGESS;
per_core(old_task) = curr_task;
} else per_core(old_task) = NULL;
#endif
}
#if MAX_CORES > 1
else per_core(old_task) = NULL;
#endif
task_table[new_id].status = TASK_RUNNING;
curr_task = per_core(current_task) = task_table+new_id;
@ -853,8 +861,10 @@ void scheduler(void)
// kprintf("task switch %d is in progress\n", new_id);
}
#if MAX_CORES > 1
// old task will never rescheduled
per_core(old_task) = NULL;
#endif
if ((curr_task->status == TASK_RUNNING) || (curr_task->status == TASK_IDLE))
goto get_task_out;