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/* Fixed-priority scheduler support.
*/
#ifndef __FP_COMMON_H__
#define __FP_COMMON_H__
#include <litmus/rt_domain.h>
#include <asm/bitops.h>
void fp_domain_init(rt_domain_t* rt, check_resched_needed_t resched,
release_jobs_t release);
int fp_higher_prio(struct task_struct* first,
struct task_struct* second);
int fp_ready_order(struct bheap_node* a, struct bheap_node* b);
#define FP_PRIO_BIT_WORDS (LITMUS_MAX_PRIORITY / BITS_PER_LONG)
#if (LITMUS_MAX_PRIORITY % BITS_PER_LONG)
#error LITMUS_MAX_PRIORITY must be a multiple of BITS_PER_LONG
#endif
/* bitmask-inexed priority queue */
struct fp_prio_queue {
unsigned long bitmask[FP_PRIO_BIT_WORDS];
struct bheap queue[LITMUS_MAX_PRIORITY];
};
void fp_prio_queue_init(struct fp_prio_queue* q);
static inline void fpq_set(struct fp_prio_queue* q, unsigned int index)
{
unsigned long *word = q->bitmask + (index / BITS_PER_LONG);
__set_bit(index % BITS_PER_LONG, word);
}
static inline void fpq_clear(struct fp_prio_queue* q, unsigned int index)
{
unsigned long *word = q->bitmask + (index / BITS_PER_LONG);
__clear_bit(index % BITS_PER_LONG, word);
}
static inline unsigned int fpq_find(struct fp_prio_queue* q)
{
int i;
/* loop optimizer should unroll this */
for (i = 0; i < FP_PRIO_BIT_WORDS; i++)
if (q->bitmask[i])
return __ffs(q->bitmask[i]) + i * BITS_PER_LONG;
return LITMUS_MAX_PRIORITY; /* nothing found */
}
static inline void fp_prio_add(struct fp_prio_queue* q, struct task_struct* t, unsigned int index)
{
BUG_ON(bheap_node_in_heap(tsk_rt(t)->heap_node));
fpq_set(q, index);
bheap_insert(fp_ready_order, &q->queue[index], tsk_rt(t)->heap_node);
}
static inline void fp_prio_remove(struct fp_prio_queue* q, struct task_struct* t, unsigned int index)
{
BUG_ON(!is_queued(t));
bheap_delete(fp_ready_order, &q->queue[index], tsk_rt(t)->heap_node);
if (likely(bheap_empty(&q->queue[index])))
fpq_clear(q, index);
}
static inline struct task_struct* fp_prio_peek(struct fp_prio_queue* q)
{
unsigned int idx = fpq_find(q);
struct bheap_node* hn;
if (idx < LITMUS_MAX_PRIORITY) {
hn = bheap_peek(fp_ready_order, &q->queue[idx]);
return bheap2task(hn);
} else
return NULL;
}
static inline struct task_struct* fp_prio_take(struct fp_prio_queue* q)
{
unsigned int idx = fpq_find(q);
struct bheap_node* hn;
if (idx < LITMUS_MAX_PRIORITY) {
hn = bheap_take(fp_ready_order, &q->queue[idx]);
if (likely(bheap_empty(&q->queue[idx])))
fpq_clear(q, idx);
return bheap2task(hn);
} else
return NULL;
}
int fp_preemption_needed(struct fp_prio_queue* q, struct task_struct *t);
#endif
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