===================================================================
@@ -174,6 +174,9 @@ struct cfq_data {
unsigned int cfq_slice_async_rq;
unsigned int cfq_slice_idle;
unsigned int cfq_desktop;
+ unsigned int cfq_desktop_dispatch;
+
+ unsigned long desktop_dispatch_ts;
struct list_head cic_list;
@@ -1283,6 +1286,7 @@ static int cfq_dispatch_requests(struct
struct cfq_data *cfqd = q->elevator->elevator_data;
struct cfq_queue *cfqq;
unsigned int max_dispatch;
+ unsigned long delay;
if (!cfqd->busy_queues)
return 0;
@@ -1297,19 +1301,26 @@ static int cfq_dispatch_requests(struct
/*
* Drain async requests before we start sync IO
*/
- if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC])
+ if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC]) {
+ cfqd->desktop_dispatch_ts = jiffies;
return 0;
+ }
/*
* If this is an async queue and we have sync IO in flight, let it wait
*/
- if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
+ if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq)) {
+ cfqd->desktop_dispatch_ts = jiffies;
return 0;
+ }
max_dispatch = cfqd->cfq_quantum;
if (cfq_class_idle(cfqq))
max_dispatch = 1;
+ if (cfqd->busy_queues > 1)
+ cfqd->desktop_dispatch_ts = jiffies;
+
/*
* Does this cfqq already have too much IO in flight?
*/
@@ -1327,6 +1338,16 @@ static int cfq_dispatch_requests(struct
return 0;
/*
+ * Don't start overloading until we've been alone for a bit.
+ */
+ if (cfqd->cfq_desktop_dispatch) {
+ delay = cfqd->desktop_dispatch_ts + cfq_slice_sync;
+
+ if (time_before(jiffies, max_delay))
+ return 0;
+ }
+
+ /*
* we are the only queue, allow up to 4 times of 'quantum'
*/
if (cfqq->dispatched >= 4 * max_dispatch)
@@ -1942,7 +1963,7 @@ static void
cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
struct cfq_io_context *cic)
{
- int old_idle, enable_idle;
+ int old_idle, enable_idle, seeky = 0;
/*
* Don't idle for async or idle io prio class
@@ -1950,10 +1971,20 @@ cfq_update_idle_window(struct cfq_data *
if (!cfq_cfqq_sync(cfqq) || cfq_class_idle(cfqq))
return;
+ if (cfqd->hw_tag) {
+ if (CIC_SEEKY(cic))
+ seeky = 1;
+ /*
+ * If seeky or incalculable seekiness, delay overloading.
+ */
+ if (seeky || !sample_valid(cic->seek_samples))
+ cfqd->desktop_dispatch_ts = jiffies;
+ }
+
enable_idle = old_idle = cfq_cfqq_idle_window(cfqq);
if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
- (!cfqd->cfq_desktop && cfqd->hw_tag && CIC_SEEKY(cic)))
+ (!cfqd->cfq_desktop && seeky))
enable_idle = 0;
else if (sample_valid(cic->ttime_samples)) {
if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -2483,6 +2514,9 @@ static void *cfq_init_queue(struct reque
cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
cfqd->cfq_slice_idle = cfq_slice_idle;
cfqd->cfq_desktop = 1;
+ cfqd->cfq_desktop_dispatch = 1;
+
+ cfqd->desktop_dispatch_ts = INITIAL_JIFFIES;
cfqd->hw_tag = 1;
return cfqd;
@@ -2553,6 +2587,7 @@ SHOW_FUNCTION(cfq_slice_sync_show, cfqd-
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_desktop_show, cfqd->cfq_desktop, 0);
+SHOW_FUNCTION(cfq_desktop_dispatch_show, cfqd->cfq_desktop_dispatch, 0);
#undef SHOW_FUNCTION
#define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV) \
@@ -2585,6 +2620,7 @@ STORE_FUNCTION(cfq_slice_async_store, &c
STORE_FUNCTION(cfq_slice_async_rq_store, &cfqd->cfq_slice_async_rq, 1,
UINT_MAX, 0);
STORE_FUNCTION(cfq_desktop_store, &cfqd->cfq_desktop, 0, 1, 0);
+STORE_FUNCTION(cfq_desktop_dispatch_store, &cfqd->cfq_desktop_dispatch, 0, 1, 0);
#undef STORE_FUNCTION
#define CFQ_ATTR(name) \
@@ -2601,6 +2637,7 @@ static struct elv_fs_entry cfq_attrs[] =
CFQ_ATTR(slice_async_rq),
CFQ_ATTR(slice_idle),
CFQ_ATTR(desktop),
+ CFQ_ATTR(desktop_dispatch),
__ATTR_NULL
};