cfq-iosched: add a knob for desktop interactiveness

[safe/jmp/linux-2.6] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 85208dd..8917f2b 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -134,13 +134,8 @@ struct cfq_data {
        struct rb_root prio_trees[CFQ_PRIO_LISTS];
 
        unsigned int busy_queues;
-       /*
-        * Used to track any pending rt requests so we can pre-empt current
-        * non-RT cfqq in service when this value is non-zero.
-        */
-       unsigned int busy_rt_queues;
 
-       int rq_in_driver;
+       int rq_in_driver[2];
        int sync_flight;
 
        /*
@@ -178,6 +173,7 @@ struct cfq_data {
        unsigned int cfq_slice[2];
        unsigned int cfq_slice_async_rq;
        unsigned int cfq_slice_idle;
+       unsigned int cfq_desktop;
 
        struct list_head cic_list;
 
@@ -191,7 +187,6 @@ enum cfqq_state_flags {
        CFQ_CFQQ_FLAG_on_rr = 0,        /* on round-robin busy list */
        CFQ_CFQQ_FLAG_wait_request,     /* waiting for a request */
        CFQ_CFQQ_FLAG_must_dispatch,    /* must be allowed a dispatch */
-       CFQ_CFQQ_FLAG_must_alloc,       /* must be allowed rq alloc */
        CFQ_CFQQ_FLAG_must_alloc_slice, /* per-slice must_alloc flag */
        CFQ_CFQQ_FLAG_fifo_expire,      /* FIFO checked in this slice */
        CFQ_CFQQ_FLAG_idle_window,      /* slice idling enabled */
@@ -218,7 +213,6 @@ static inline int cfq_cfqq_##name(const struct cfq_queue *cfqq)             \
 CFQ_CFQQ_FNS(on_rr);
 CFQ_CFQQ_FNS(wait_request);
 CFQ_CFQQ_FNS(must_dispatch);
-CFQ_CFQQ_FNS(must_alloc);
 CFQ_CFQQ_FNS(must_alloc_slice);
 CFQ_CFQQ_FNS(fifo_expire);
 CFQ_CFQQ_FNS(idle_window);
@@ -239,6 +233,11 @@ static struct cfq_queue *cfq_get_queue(struct cfq_data *, int,
 static struct cfq_io_context *cfq_cic_lookup(struct cfq_data *,
                                                struct io_context *);
 
+static inline int rq_in_driver(struct cfq_data *cfqd)
+{
+       return cfqd->rq_in_driver[0] + cfqd->rq_in_driver[1];
+}
+
 static inline struct cfq_queue *cic_to_cfqq(struct cfq_io_context *cic,
                                            int is_sync)
 {
@@ -257,7 +256,7 @@ static inline void cic_set_cfqq(struct cfq_io_context *cic,
  */
 static inline int cfq_bio_sync(struct bio *bio)
 {
-       if (bio_data_dir(bio) == READ || bio_sync(bio))
+       if (bio_data_dir(bio) == READ || bio_rw_flagged(bio, BIO_RW_SYNCIO))
                return 1;
 
        return 0;
@@ -648,8 +647,6 @@ static void cfq_add_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
        BUG_ON(cfq_cfqq_on_rr(cfqq));
        cfq_mark_cfqq_on_rr(cfqq);
        cfqd->busy_queues++;
-       if (cfq_class_rt(cfqq))
-               cfqd->busy_rt_queues++;
 
        cfq_resort_rr_list(cfqd, cfqq);
 }
@@ -673,8 +670,6 @@ static void cfq_del_cfqq_rr(struct cfq_data *cfqd, struct cfq_queue *cfqq)
 
        BUG_ON(!cfqd->busy_queues);
        cfqd->busy_queues--;
-       if (cfq_class_rt(cfqq))
-               cfqd->busy_rt_queues--;
 }
 
 /*
@@ -760,9 +755,9 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
 
-       cfqd->rq_in_driver++;
+       cfqd->rq_in_driver[rq_is_sync(rq)]++;
        cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "activate rq, drv=%d",
-                                               cfqd->rq_in_driver);
+                                               rq_in_driver(cfqd));
 
        cfqd->last_position = blk_rq_pos(rq) + blk_rq_sectors(rq);
 }
@@ -770,11 +765,12 @@ static void cfq_activate_request(struct request_queue *q, struct request *rq)
 static void cfq_deactivate_request(struct request_queue *q, struct request *rq)
 {
        struct cfq_data *cfqd = q->elevator->elevator_data;
+       const int sync = rq_is_sync(rq);
 
-       WARN_ON(!cfqd->rq_in_driver);
-       cfqd->rq_in_driver--;
+       WARN_ON(!cfqd->rq_in_driver[sync]);
+       cfqd->rq_in_driver[sync]--;
        cfq_log_cfqq(cfqd, RQ_CFQQ(rq), "deactivate rq, drv=%d",
-                                               cfqd->rq_in_driver);
+                                               rq_in_driver(cfqd));
 }
 
 static void cfq_remove_request(struct request *rq)
@@ -1080,7 +1076,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
        /*
         * still requests with the driver, don't idle
         */
-       if (cfqd->rq_in_driver)
+       if (rq_in_driver(cfqd))
                return;
 
        /*
@@ -1115,6 +1111,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
 
        cfq_log_cfqq(cfqd, cfqq, "dispatch_insert");
 
+       cfqq->next_rq = cfq_find_next_rq(cfqd, cfqq, rq);
        cfq_remove_request(rq);
        cfqq->dispatched++;
        elv_dispatch_sort(q, rq);
@@ -1179,20 +1176,6 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
                goto expire;
 
        /*
-        * If we have a RT cfqq waiting, then we pre-empt the current non-rt
-        * cfqq.
-        */
-       if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues) {
-               /*
-                * We simulate this as cfqq timed out so that it gets to bank
-                * the remaining of its time slice.
-                */
-               cfq_log_cfqq(cfqd, cfqq, "preempt");
-               cfq_slice_expired(cfqd, 1);
-               goto new_queue;
-       }
-
-       /*
         * The active queue has requests and isn't expired, allow it to
         * dispatch.
         */
@@ -1312,6 +1295,12 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
                return 0;
 
        /*
+        * Drain async requests before we start sync IO
+        */
+       if (cfq_cfqq_idle_window(cfqq) && cfqd->rq_in_driver[BLK_RW_ASYNC])
+               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))
@@ -1362,7 +1351,7 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
                cfq_slice_expired(cfqd, 0);
        }
 
-       cfq_log(cfqd, "dispatched a request");
+       cfq_log_cfqq(cfqd, cfqq, "dispatched a request");
        return 1;
 }
 
@@ -1963,7 +1952,7 @@ 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_desktop && cfqd->hw_tag && CIC_SEEKY(cic)))
                enable_idle = 0;
        else if (sample_valid(cic->ttime_samples)) {
                if (cic->ttime_mean > cfqd->cfq_slice_idle)
@@ -2130,11 +2119,11 @@ static void cfq_insert_request(struct request_queue *q, struct request *rq)
  */
 static void cfq_update_hw_tag(struct cfq_data *cfqd)
 {
-       if (cfqd->rq_in_driver > cfqd->rq_in_driver_peak)
-               cfqd->rq_in_driver_peak = cfqd->rq_in_driver;
+       if (rq_in_driver(cfqd) > cfqd->rq_in_driver_peak)
+               cfqd->rq_in_driver_peak = rq_in_driver(cfqd);
 
        if (cfqd->rq_queued <= CFQ_HW_QUEUE_MIN &&
-           cfqd->rq_in_driver <= CFQ_HW_QUEUE_MIN)
+           rq_in_driver(cfqd) <= CFQ_HW_QUEUE_MIN)
                return;
 
        if (cfqd->hw_tag_samples++ < 50)
@@ -2161,9 +2150,9 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
 
        cfq_update_hw_tag(cfqd);
 
-       WARN_ON(!cfqd->rq_in_driver);
+       WARN_ON(!cfqd->rq_in_driver[sync]);
        WARN_ON(!cfqq->dispatched);
-       cfqd->rq_in_driver--;
+       cfqd->rq_in_driver[sync]--;
        cfqq->dispatched--;
 
        if (cfq_cfqq_sync(cfqq))
@@ -2197,7 +2186,7 @@ static void cfq_completed_request(struct request_queue *q, struct request *rq)
                        cfq_arm_slice_timer(cfqd);
        }
 
-       if (!cfqd->rq_in_driver)
+       if (!rq_in_driver(cfqd))
                cfq_schedule_dispatch(cfqd);
 }
 
@@ -2229,8 +2218,7 @@ static void cfq_prio_boost(struct cfq_queue *cfqq)
 
 static inline int __cfq_may_queue(struct cfq_queue *cfqq)
 {
-       if ((cfq_cfqq_wait_request(cfqq) || cfq_cfqq_must_alloc(cfqq)) &&
-           !cfq_cfqq_must_alloc_slice(cfqq)) {
+       if (cfq_cfqq_wait_request(cfqq) && !cfq_cfqq_must_alloc_slice(cfqq)) {
                cfq_mark_cfqq_must_alloc_slice(cfqq);
                return ELV_MQUEUE_MUST;
        }
@@ -2311,13 +2299,12 @@ cfq_set_request(struct request_queue *q, struct request *rq, gfp_t gfp_mask)
                goto queue_fail;
 
        cfqq = cic_to_cfqq(cic, is_sync);
-       if (!cfqq) {
+       if (!cfqq || cfqq == &cfqd->oom_cfqq) {
                cfqq = cfq_get_queue(cfqd, is_sync, cic->ioc, gfp_mask);
                cic_set_cfqq(cic, cfqq, is_sync);
        }
 
        cfqq->allocated[rw]++;
-       cfq_clear_cfqq_must_alloc(cfqq);
        atomic_inc(&cfqq->ref);
 
        spin_unlock_irqrestore(q->queue_lock, flags);
@@ -2494,6 +2481,7 @@ 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_desktop = 1;
        cfqd->hw_tag = 1;
 
        return cfqd;
@@ -2563,6 +2551,7 @@ 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_desktop_show, cfqd->cfq_desktop, 0);
 #undef SHOW_FUNCTION
 
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)                        \
@@ -2594,6 +2583,7 @@ 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_desktop_store, &cfqd->cfq_desktop, 0, 1, 0);
 #undef STORE_FUNCTION
 
 #define CFQ_ATTR(name) \
@@ -2609,6 +2599,7 @@ static struct elv_fs_entry cfq_attrs[] = {
        CFQ_ATTR(slice_async),
        CFQ_ATTR(slice_async_rq),
        CFQ_ATTR(slice_idle),
+       CFQ_ATTR(desktop),
        __ATTR_NULL
 };