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-rw-r--r--block/cfq-iosched.c63
1 files changed, 46 insertions, 17 deletions
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 1ca813b16e78..9c4b679908f4 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -150,7 +150,7 @@ struct cfq_data {
* idle window management
*/
struct timer_list idle_slice_timer;
- struct work_struct unplug_work;
+ struct delayed_work unplug_work;
struct cfq_queue *active_queue;
struct cfq_io_context *active_cic;
@@ -173,6 +173,7 @@ struct cfq_data {
unsigned int cfq_slice[2];
unsigned int cfq_slice_async_rq;
unsigned int cfq_slice_idle;
+ unsigned int cfq_latency;
struct list_head cic_list;
@@ -180,6 +181,8 @@ struct cfq_data {
* Fallback dummy cfqq for extreme OOM conditions
*/
struct cfq_queue oom_cfqq;
+
+ unsigned long last_end_sync_rq;
};
enum cfqq_state_flags {
@@ -265,11 +268,13 @@ static inline int cfq_bio_sync(struct bio *bio)
* scheduler run of queue, if there are requests pending and no one in the
* driver that will restart queueing
*/
-static inline void cfq_schedule_dispatch(struct cfq_data *cfqd)
+static inline void cfq_schedule_dispatch(struct cfq_data *cfqd,
+ unsigned long delay)
{
if (cfqd->busy_queues) {
cfq_log(cfqd, "schedule dispatch");
- kblockd_schedule_work(cfqd->queue, &cfqd->unplug_work);
+ kblockd_schedule_delayed_work(cfqd->queue, &cfqd->unplug_work,
+ delay);
}
}
@@ -1326,12 +1331,30 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
return 0;
/*
- * we are the only queue, allow up to 4 times of 'quantum'
+ * Sole queue user, allow bigger slice
*/
- if (cfqq->dispatched >= 4 * max_dispatch)
- return 0;
+ max_dispatch *= 4;
+ }
+
+ /*
+ * Async queues must wait a bit before being allowed dispatch.
+ * We also ramp up the dispatch depth gradually for async IO,
+ * based on the last sync IO we serviced
+ */
+ if (!cfq_cfqq_sync(cfqq) && cfqd->cfq_latency) {
+ unsigned long last_sync = jiffies - cfqd->last_end_sync_rq;
+ unsigned int depth;
+
+ depth = last_sync / cfqd->cfq_slice[1];
+ if (!depth && !cfqq->dispatched)
+ depth = 1;
+ if (depth < max_dispatch)
+ max_dispatch = depth;
}
+ if (cfqq->dispatched >= max_dispatch)
+ return 0;
+
/*
* Dispatch a request from this cfqq
*/
@@ -1376,7 +1399,7 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
if (unlikely(cfqd->active_queue == cfqq)) {
__cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
+ cfq_schedule_dispatch(cfqd, 0);
}
kmem_cache_free(cfq_pool, cfqq);
@@ -1471,7 +1494,7 @@ static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
{
if (unlikely(cfqq == cfqd->active_queue)) {
__cfq_slice_expired(cfqd, cfqq, 0);
- cfq_schedule_dispatch(cfqd);
+ cfq_schedule_dispatch(cfqd, 0);
}
cfq_put_queue(cfqq);
@@ -1951,7 +1974,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (cfqd->hw_tag && CIC_SEEKY(cic)))
+ (!cfqd->cfq_latency && cfqd->hw_tag && CIC_SEEKY(cic)))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -2157,8 +2180,10 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
if (cfq_cfqq_sync(cfqq))
cfqd->sync_flight--;
- if (sync)
+ if (sync) {
RQ_CIC(rq)->last_end_request = now;
+ cfqd->last_end_sync_rq = now;
+ }
/*
* If this is the active queue, check if it needs to be expired,
@@ -2186,7 +2211,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
}
if (!rq_in_driver(cfqd))
- cfq_schedule_dispatch(cfqd);
+ cfq_schedule_dispatch(cfqd, 0);
}
/*
@@ -2316,7 +2341,7 @@ queue_fail:
if (cic)
put_io_context(cic->ioc);
- cfq_schedule_dispatch(cfqd);
+ cfq_schedule_dispatch(cfqd, 0);
spin_unlock_irqrestore(q->queue_lock, flags);
cfq_log(cfqd, "set_request fail");
return 1;
@@ -2325,7 +2350,7 @@ queue_fail:
static void cfq_kick_queue(struct work_struct *work)
{
struct cfq_data *cfqd =
- container_of(work, struct cfq_data, unplug_work);
+ container_of(work, struct cfq_data, unplug_work.work);
struct request_queue *q = cfqd->queue;
spin_lock_irq(q->queue_lock);
@@ -2379,7 +2404,7 @@ static void cfq_idle_slice_timer(unsigned long data)
expire:
cfq_slice_expired(cfqd, timed_out);
out_kick:
- cfq_schedule_dispatch(cfqd);
+ cfq_schedule_dispatch(cfqd, 0);
out_cont:
spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
}
@@ -2387,7 +2412,7 @@ out_cont:
static void cfq_shutdown_timer_wq(struct cfq_data *cfqd)
{
del_timer_sync(&cfqd->idle_slice_timer);
- cancel_work_sync(&cfqd->unplug_work);
+ cancel_delayed_work_sync(&cfqd->unplug_work);
}
static void cfq_put_async_queues(struct cfq_data *cfqd)
@@ -2469,7 +2494,7 @@ static void *cfq_init_queue(struct request_queue *q)
cfqd->idle_slice_timer.function = cfq_idle_slice_timer;
cfqd->idle_slice_timer.data = (unsigned long) cfqd;
- INIT_WORK(&cfqd->unplug_work, cfq_kick_queue);
+ INIT_DELAYED_WORK(&cfqd->unplug_work, cfq_kick_queue);
cfqd->cfq_quantum = cfq_quantum;
cfqd->cfq_fifo_expire[0] = cfq_fifo_expire[0];
@@ -2480,8 +2505,9 @@ static void *cfq_init_queue(struct request_queue *q)
cfqd->cfq_slice[1] = cfq_slice_sync;
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
+ cfqd->cfq_latency = 1;
cfqd->hw_tag = 1;
-
+ cfqd->last_end_sync_rq = jiffies;
return cfqd;
}
@@ -2549,6 +2575,7 @@ SHOW_FUNCTION(cfq_slice_idle_show, cfqd->cfq_slice_idle, 1);
SHOW_FUNCTION(cfq_slice_sync_show, cfqd->cfq_slice[1], 1);
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);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
@@ -2580,6 +2607,7 @@ STORE_FUNCTION(cfq_slice_sync_store, &cfqd->cfq_slice[1], 1, UINT_MAX, 1);
STORE_FUNCTION(cfq_slice_async_store, &cfqd->cfq_slice[0], 1, UINT_MAX, 1);
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);
#undef STORE_FUNCTION
#define CFQ_ATTR(name) \
@@ -2595,6 +2623,7 @@ static struct elv_fs_entry cfq_attrs[] = {
CFQ_ATTR(slice_async),
CFQ_ATTR(slice_async_rq),
CFQ_ATTR(slice_idle),
+ CFQ_ATTR(low_latency),
__ATTR_NULL
};
Copyright © 1996 – 2023 Jason A. Donenfeld. All Rights Reverse Engineered.