--- /dev/null
+What: /sys/block/<device>/iosched/target_latency
+Date: March 2012
+contact: Tao Ma <boyu.mt@taobao.com>
+Description:
+ The /sys/block/<device>/iosched/target_latency only exists
+ when the user sets cfq to /sys/block/<device>/scheduler.
+ It contains an estimated latency time for the cfq. cfq will
+ use it to calculate the time slice used for every task.
if (!q)
return NULL;
- q->id = ida_simple_get(&blk_queue_ida, 0, 0, GFP_KERNEL);
+ q->id = ida_simple_get(&blk_queue_ida, 0, 0, gfp_mask);
if (q->id < 0)
goto fail_q;
list_for_each_entry_reverse(rq, &plug->list, queuelist) {
int el_ret;
- (*request_count)++;
+ if (rq->q == q)
+ (*request_count)++;
if (rq->q != q || !blk_rq_merge_ok(rq, bio))
continue;
struct bio_list bl;
struct bio *bio;
- WARN_ON_ONCE(!queue_is_locked(q));
+ queue_lockdep_assert_held(q);
bio_list_init(&bl);
unsigned int cfq_slice_idle;
unsigned int cfq_group_idle;
unsigned int cfq_latency;
+ unsigned int cfq_target_latency;
/*
* Fallback dummy cfqq for extreme OOM conditions
{
struct cfq_rb_root *st = &cfqd->grp_service_tree;
- return cfq_target_latency * cfqg->weight / st->total_weight;
+ return cfqd->cfq_target_latency * cfqg->weight / st->total_weight;
}
static inline unsigned
* to have higher weight. A more accurate thing would be to
* calculate system wide asnc/sync ratio.
*/
- tmp = cfq_target_latency * cfqg_busy_async_queues(cfqd, cfqg);
+ tmp = cfqd->cfq_target_latency *
+ cfqg_busy_async_queues(cfqd, cfqg);
tmp = tmp/cfqd->busy_queues;
slice = min_t(unsigned, slice, tmp);
cfqd->cfq_back_penalty = cfq_back_penalty;
cfqd->cfq_slice[0] = cfq_slice_async;
cfqd->cfq_slice[1] = cfq_slice_sync;
+ cfqd->cfq_target_latency = cfq_target_latency;
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
cfqd->cfq_group_idle = cfq_group_idle;
SHOW_FUNCTION(cfq_slice_async_show, cfqd->cfq_slice[0], 1);
SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
SHOW_FUNCTION(cfq_low_latency_show, cfqd->cfq_latency, 0);
+SHOW_FUNCTION(cfq_target_latency_show, cfqd->cfq_target_latency, 1);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
UINT_MAX, 0);
STORE_FUNCTION(cfq_low_latency_store, &cfqd->cfq_latency, 0, 1, 0);
+STORE_FUNCTION(cfq_target_latency_store, &cfqd->cfq_target_latency, 1, UINT_MAX, 1);
#undef STORE_FUNCTION
#define CFQ_ATTR(name) \
CFQ_ATTR(slice_idle),
CFQ_ATTR(group_idle),
CFQ_ATTR(low_latency),
+ CFQ_ATTR(target_latency),
__ATTR_NULL
};
(1 << QUEUE_FLAG_SAME_COMP) | \
(1 << QUEUE_FLAG_ADD_RANDOM))
-static inline int queue_is_locked(struct request_queue *q)
+static inline void queue_lockdep_assert_held(struct request_queue *q)
{
-#ifdef CONFIG_SMP
- spinlock_t *lock = q->queue_lock;
- return lock && spin_is_locked(lock);
-#else
- return 1;
-#endif
+ if (q->queue_lock)
+ lockdep_assert_held(q->queue_lock);
}
static inline void queue_flag_set_unlocked(unsigned int flag,
static inline int queue_flag_test_and_clear(unsigned int flag,
struct request_queue *q)
{
- WARN_ON_ONCE(!queue_is_locked(q));
+ queue_lockdep_assert_held(q);
if (test_bit(flag, &q->queue_flags)) {
__clear_bit(flag, &q->queue_flags);
static inline int queue_flag_test_and_set(unsigned int flag,
struct request_queue *q)
{
- WARN_ON_ONCE(!queue_is_locked(q));
+ queue_lockdep_assert_held(q);
if (!test_bit(flag, &q->queue_flags)) {
__set_bit(flag, &q->queue_flags);
static inline void queue_flag_set(unsigned int flag, struct request_queue *q)
{
- WARN_ON_ONCE(!queue_is_locked(q));
+ queue_lockdep_assert_held(q);
__set_bit(flag, &q->queue_flags);
}
static inline void queue_flag_clear(unsigned int flag, struct request_queue *q)
{
- WARN_ON_ONCE(!queue_is_locked(q));
+ queue_lockdep_assert_held(q);
__clear_bit(flag, &q->queue_flags);
}