firesat: avc resend

[linux-2.6-block.git] / block / cfq-iosched.c

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index a2bfec7d6b3618b928de63ab96303df8079d665b..664ebfd092ec21f95cedc56b6a5259874db0399c 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -84,6 +84,11 @@ struct cfq_data {
         */
        struct cfq_rb_root service_tree;
        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 sync_flight;
@@ -562,6 +567,8 @@ 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);
 }
@@ -581,6 +588,8 @@ 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--;
 }
 
 /*
@@ -1004,6 +1013,20 @@ static struct cfq_queue *cfq_select_queue(struct cfq_data *cfqd)
        if (cfq_slice_used(cfqq))
                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.
@@ -1067,6 +1090,13 @@ __cfq_dispatch_requests(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                if (RB_EMPTY_ROOT(&cfqq->sort_list))
                        break;
 
+               /*
+                * If there is a non-empty RT cfqq waiting for current
+                * cfqq's timeslice to complete, pre-empt this cfqq
+                */
+               if (!cfq_class_rt(cfqq) && cfqd->busy_rt_queues)
+                       break;
+
        } while (dispatched < max_dispatch);
 
        /*
@@ -1136,12 +1166,8 @@ static int cfq_dispatch_requests(struct request_queue *q, int force)
                if (cfq_class_idle(cfqq))
                        max_dispatch = 1;
 
-               if (cfqq->dispatched >= max_dispatch) {
-                       if (cfqd->busy_queues > 1)
-                               break;
-                       if (cfqq->dispatched >= 4 * max_dispatch)
-                               break;
-               }
+               if (cfqq->dispatched >= max_dispatch && cfqd->busy_queues > 1)
+                       break;
 
                if (cfqd->sync_flight && !cfq_cfqq_sync(cfqq))
                        break;
@@ -1318,7 +1344,15 @@ static void cfq_exit_single_io_context(struct io_context *ioc,
                unsigned long flags;
 
                spin_lock_irqsave(q->queue_lock, flags);
-               __cfq_exit_single_io_context(cfqd, cic);
+
+               /*
+                * Ensure we get a fresh copy of the ->key to prevent
+                * race between exiting task and queue
+                */
+               smp_read_barrier_depends();
+               if (cic->key)
+                       __cfq_exit_single_io_context(cfqd, cic);
+
                spin_unlock_irqrestore(q->queue_lock, flags);
        }
 }
@@ -1797,6 +1831,12 @@ cfq_should_preempt(struct cfq_data *cfqd, struct cfq_queue *new_cfqq,
        if (rq_is_meta(rq) && !cfqq->meta_pending)
                return 1;
 
+       /*
+        * Allow an RT request to pre-empt an ongoing non-RT cfqq timeslice.
+        */
+       if (cfq_class_rt(new_cfqq) && !cfq_class_rt(cfqq))
+               return 1;
+
        if (!cfqd->active_cic || !cfq_cfqq_wait_request(cfqq))
                return 0;
 
@@ -1866,7 +1906,8 @@ cfq_rq_enqueued(struct cfq_data *cfqd, struct cfq_queue *cfqq,
                /*
                 * not the active queue - expire current slice if it is
                 * idle and has expired it's mean thinktime or this new queue
-                * has some old slice time left and is of higher priority
+                * has some old slice time left and is of higher priority or
+                * this new queue is RT and the current one is BE
                 */
                cfq_preempt_queue(cfqd, cfqq);
                cfq_mark_cfqq_must_dispatch(cfqq);
@@ -2178,7 +2219,7 @@ static void cfq_put_async_queues(struct cfq_data *cfqd)
                cfq_put_queue(cfqd->async_idle_cfqq);
 }
 
-static void cfq_exit_queue(elevator_t *e)
+static void cfq_exit_queue(struct elevator_queue *e)
 {
        struct cfq_data *cfqd = e->elevator_data;
        struct request_queue *q = cfqd->queue;
@@ -2288,7 +2329,7 @@ cfq_var_store(unsigned int *var, const char *page, size_t count)
 }
 
 #define SHOW_FUNCTION(__FUNC, __VAR, __CONV)                           \
-static ssize_t __FUNC(elevator_t *e, char *page)                       \
+static ssize_t __FUNC(struct elevator_queue *e, char *page)            \
 {                                                                      \
        struct cfq_data *cfqd = e->elevator_data;                       \
        unsigned int __data = __VAR;                                    \
@@ -2308,7 +2349,7 @@ SHOW_FUNCTION(cfq_slice_async_rq_show, cfqd->cfq_slice_async_rq, 0);
 #undef SHOW_FUNCTION
 
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)                        \
-static ssize_t __FUNC(elevator_t *e, const char *page, size_t count)   \
+static ssize_t __FUNC(struct elevator_queue *e, const char *page, size_t count)        \
 {                                                                      \
        struct cfq_data *cfqd = e->elevator_data;                       \
        unsigned int __data;                                            \