io_context sharing - cfq changes

changes in the cfq for io_context sharing

Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 533af75329e6293699ab7e8c8d201458ace892fb..dba52b62cef850c0e2102b54caa8eb89ffe2422a 100644 (file)
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -895,7 +895,7 @@ static void cfq_arm_slice_timer(struct cfq_data *cfqd)
         * task has exited, don't wait
         */
        cic = cfqd->active_cic;
-       if (!cic || !cic->ioc->task)
+       if (!cic || !atomic_read(&cic->ioc->nr_tasks))
                return;
 
        /*
@@ -1178,6 +1178,8 @@ static void cfq_free_io_context(struct io_context *ioc)
 
        ioc->ioc_data = NULL;
 
+       spin_lock(&ioc->lock);
+
        while ((n = rb_first(&ioc->cic_root)) != NULL) {
                __cic = rb_entry(n, struct cfq_io_context, rb_node);
                rb_erase(&__cic->rb_node, &ioc->cic_root);
@@ -1189,6 +1191,8 @@ static void cfq_free_io_context(struct io_context *ioc)
 
        if (ioc_gone && !elv_ioc_count_read(ioc_count))
                complete(ioc_gone);
+
+       spin_unlock(&ioc->lock);
 }
 
 static void cfq_exit_cfqq(struct cfq_data *cfqd, struct cfq_queue *cfqq)
@@ -1243,6 +1247,7 @@ static void cfq_exit_io_context(struct io_context *ioc)
 
        ioc->ioc_data = NULL;
 
+       spin_lock(&ioc->lock);
        /*
         * put the reference this task is holding to the various queues
         */
@@ -1253,6 +1258,8 @@ static void cfq_exit_io_context(struct io_context *ioc)
                cfq_exit_single_io_context(__cic);
                n = rb_next(n);
        }
+
+       spin_unlock(&ioc->lock);
 }
 
 static struct cfq_io_context *
@@ -1349,6 +1356,8 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)
        struct cfq_io_context *cic;
        struct rb_node *n;
 
+       spin_lock(&ioc->lock);
+
        ioc->ioprio_changed = 0;
 
        n = rb_first(&ioc->cic_root);
@@ -1358,6 +1367,8 @@ static void cfq_ioc_set_ioprio(struct io_context *ioc)
                changed_ioprio(cic);
                n = rb_next(n);
        }
+
+       spin_unlock(&ioc->lock);
 }
 
 static struct cfq_queue *
@@ -1502,6 +1513,7 @@ cfq_cic_rb_lookup(struct cfq_data *cfqd, struct io_context *ioc)
        if (cic && cic->key == cfqd)
                return cic;
 
+       spin_lock(&ioc->lock);
 restart:
        n = ioc->cic_root.rb_node;
        while (n) {
@@ -1519,10 +1531,12 @@ restart:
                        n = n->rb_right;
                else {
                        ioc->ioc_data = cic;
+                       spin_unlock(&ioc->lock);
                        return cic;
                }
        }
 
+       spin_unlock(&ioc->lock);
        return NULL;
 }
 
@@ -1536,6 +1550,7 @@ cfq_cic_link(struct cfq_data *cfqd, struct io_context *ioc,
        unsigned long flags;
        void *k;
 
+       spin_lock(&ioc->lock);
        cic->ioc = ioc;
        cic->key = cfqd;
 
@@ -1566,6 +1581,7 @@ restart:
        spin_lock_irqsave(cfqd->queue->queue_lock, flags);
        list_add(&cic->queue_list, &cfqd->cic_list);
        spin_unlock_irqrestore(cfqd->queue->queue_lock, flags);
+       spin_unlock(&ioc->lock);
 }
 
 /*
@@ -1659,7 +1675,7 @@ cfq_update_idle_window(struct cfq_data *cfqd, struct cfq_queue *cfqq,
 
        enable_idle = cfq_cfqq_idle_window(cfqq);
 
-       if (!cic->ioc->task || !cfqd->cfq_slice_idle ||
+       if (!atomic_read(&cic->ioc->nr_tasks) || !cfqd->cfq_slice_idle ||
            (cfqd->hw_tag && CIC_SEEKY(cic)))
                enable_idle = 0;
        else if (sample_valid(cic->ttime_samples)) {