1 files changed, 36 insertions, 1 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index b9e483d9031e..063dcbb714e7 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -144,6 +144,7 @@ struct cfq_queue {
         struct cfq_rb_root *service_tree;
         struct cfq_queue *new_cfqq;
         struct cfq_group *cfqg;
+        struct cfq_group *orig_cfqg;
         /* Sectors dispatched in current dispatch round */
         unsigned long nr_sectors;
 };
@@ -273,6 +274,7 @@ struct cfq_data {
         unsigned int cfq_slice_async_rq;
         unsigned int cfq_slice_idle;
         unsigned int cfq_latency;
+        unsigned int cfq_group_isolation;
 
         struct list_head cic_list;
 
@@ -1120,6 +1122,33 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         struct cfq_rb_root *service_tree;
         int left;
         int new_cfqq = 1;
+        int group_changed = 0;
+
+#ifdef CONFIG_CFQ_GROUP_IOSCHED
+        if (!cfqd->cfq_group_isolation
+            && cfqq_type(cfqq) == SYNC_NOIDLE_WORKLOAD
+            && cfqq->cfqg && cfqq->cfqg != &cfqd->root_group) {
+                /* Move this cfq to root group */
+                cfq_log_cfqq(cfqd, cfqq, "moving to root group");
+                if (!RB_EMPTY_NODE(&cfqq->rb_node))
+                        cfq_group_service_tree_del(cfqd, cfqq->cfqg);
+                cfqq->orig_cfqg = cfqq->cfqg;
+                cfqq->cfqg = &cfqd->root_group;
+                atomic_inc(&cfqd->root_group.ref);
+                group_changed = 1;
+        } else if (!cfqd->cfq_group_isolation
+                   && cfqq_type(cfqq) == SYNC_WORKLOAD && cfqq->orig_cfqg) {
+                /* cfqq is sequential now needs to go to its original group */
+                BUG_ON(cfqq->cfqg != &cfqd->root_group);
+                if (!RB_EMPTY_NODE(&cfqq->rb_node))
+                        cfq_group_service_tree_del(cfqd, cfqq->cfqg);
+                cfq_put_cfqg(cfqq->cfqg);
+                cfqq->cfqg = cfqq->orig_cfqg;
+                cfqq->orig_cfqg = NULL;
+                group_changed = 1;
+                cfq_log_cfqq(cfqd, cfqq, "moved to origin group");
+        }
+#endif
 
         service_tree = service_tree_for(cfqq->cfqg, cfqq_prio(cfqq),
                                                 cfqq_type(cfqq), cfqd);
@@ -1190,7 +1219,7 @@ static void cfq_service_tree_add(struct cfq_data *cfqd, struct cfq_queue *cfqq,
         rb_link_node(&cfqq->rb_node, parent, p);
         rb_insert_color(&cfqq->rb_node, &service_tree->rb);
         service_tree->count++;
-        if (add_front || !new_cfqq)
+        if ((add_front || !new_cfqq) && !group_changed)
                 return;
         cfq_group_service_tree_add(cfqd, cfqq->cfqg);
 }
@@ -2357,6 +2386,8 @@ static void cfq_put_queue(struct cfq_queue *cfqq)
         BUG_ON(cfq_cfqq_on_rr(cfqq));
         kmem_cache_free(cfq_pool, cfqq);
         cfq_put_cfqg(cfqg);
+        if (cfqq->orig_cfqg)
+                cfq_put_cfqg(cfqq->orig_cfqg);
 }
 
 /*
@@ -3670,6 +3701,7 @@ static void *cfq_init_queue(struct request_queue *q)
         cfqd->cfq_slice_async_rq = cfq_slice_async_rq;
         cfqd->cfq_slice_idle = cfq_slice_idle;
         cfqd->cfq_latency = 1;
+        cfqd->cfq_group_isolation = 0;
         cfqd->hw_tag = -1;
         cfqd->last_end_sync_rq = jiffies;
         return cfqd;
@@ -3740,6 +3772,7 @@ 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);
+SHOW_FUNCTION(cfq_group_isolation_show, cfqd->cfq_group_isolation, 0);
 #undef SHOW_FUNCTION
 
 #define STORE_FUNCTION(__FUNC, __PTR, MIN, MAX, __CONV)                 \
@@ -3772,6 +3805,7 @@ 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);
+STORE_FUNCTION(cfq_group_isolation_store, &cfqd->cfq_group_isolation, 0, 1, 0);
 #undef STORE_FUNCTION
 
 #define CFQ_ATTR(name) \
@@ -3788,6 +3822,7 @@ static struct elv_fs_entry cfq_attrs[] = {
         CFQ_ATTR(slice_async_rq),
         CFQ_ATTR(slice_idle),
         CFQ_ATTR(low_latency),
+        CFQ_ATTR(group_isolation),
         __ATTR_NULL
 };