blkio: Export disk time and sectors used by a group to user space

o Export disk time and sector used by a group to user space through cgroup
  interface.

o Also export a "dequeue" interface to cgroup which keeps track of how many
  a times a group was deleted from service tree. Helps in debugging.

Signed-off-by: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <jens.axboe@oracle.com>

1 files changed, 16 insertions, 3 deletions

diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index 662d4e55b3c2..7d345e772d88 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -143,6 +143,8 @@ struct cfq_queue {
         struct cfq_rb_root *service_tree;
         struct cfq_queue *new_cfqq;
         struct cfq_group *cfqg;
+        /* Sectors dispatched in current dispatch round */
+        unsigned long nr_sectors;
 };
 
 /*
@@ -852,6 +854,7 @@ cfq_group_service_tree_del(struct cfq_data *cfqd, struct cfq_group *cfqg)
         if (!RB_EMPTY_NODE(&cfqg->rb_node))
                 cfq_rb_erase(&cfqg->rb_node, st);
         cfqg->saved_workload_slice = 0;
+        blkiocg_update_blkio_group_dequeue_stats(&cfqg->blkg, 1);
 }
 
 static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
@@ -878,7 +881,8 @@ static inline unsigned int cfq_cfqq_slice_usage(struct cfq_queue *cfqq)
                         slice_used = allocated_slice;
         }
 
-        cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u", slice_used);
+        cfq_log_cfqq(cfqq->cfqd, cfqq, "sl_used=%u sect=%lu", slice_used,
+                                cfqq->nr_sectors);
         return slice_used;
 }
 
@@ -906,6 +910,8 @@ static void cfq_group_served(struct cfq_data *cfqd, struct cfq_group *cfqg,
 
         cfq_log_cfqg(cfqd, cfqg, "served: vt=%llu min_vt=%llu", cfqg->vdisktime,
                                         st->min_vdisktime);
+        blkiocg_update_blkio_group_stats(&cfqg->blkg, used_sl,
+                                                cfqq->nr_sectors);
 }
 
 #ifdef CONFIG_CFQ_GROUP_IOSCHED
@@ -924,6 +930,8 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
         void *key = cfqd;
         int i, j;
         struct cfq_rb_root *st;
+        struct backing_dev_info *bdi = &cfqd->queue->backing_dev_info;
+        unsigned int major, minor;
 
         /* Do we need to take this reference */
         if (!css_tryget(&blkcg->css))
@@ -951,7 +959,9 @@ cfq_find_alloc_cfqg(struct cfq_data *cfqd, struct cgroup *cgroup, int create)
         atomic_set(&cfqg->ref, 1);
 
         /* Add group onto cgroup list */
-        blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd);
+        sscanf(dev_name(bdi->dev), "%u:%u", &major, &minor);
+        blkiocg_add_blkio_group(blkcg, &cfqg->blkg, (void *)cfqd,
+                                        MKDEV(major, minor));
 
         /* Add group on cfqd list */
         hlist_add_head(&cfqg->cfqd_node, &cfqd->cfqg_list);
@@ -1478,6 +1488,7 @@ static void __cfq_set_active_queue(struct cfq_data *cfqd,
                 cfqq->dispatch_start = jiffies;
                 cfqq->slice_end = 0;
                 cfqq->slice_dispatch = 0;
+                cfqq->nr_sectors = 0;
 
                 cfq_clear_cfqq_wait_request(cfqq);
                 cfq_clear_cfqq_must_dispatch(cfqq);
@@ -1801,6 +1812,7 @@ static void cfq_dispatch_insert(struct request_queue *q, struct request *rq)
 
         if (cfq_cfqq_sync(cfqq))
                 cfqd->sync_flight++;
+        cfqq->nr_sectors += blk_rq_sectors(rq);
 }
 
 /*
@@ -3513,7 +3525,8 @@ static void *cfq_init_queue(struct request_queue *q)
          * to make sure that cfq_put_cfqg() does not try to kfree root group
          */
         atomic_set(&cfqg->ref, 1);
-        blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd);
+        blkiocg_add_blkio_group(&blkio_root_cgroup, &cfqg->blkg, (void *)cfqd,
+                                        0);
 #endif
         /*
          * Not strictly needed (since RB_ROOT just clears the node and we