blk-cgroup: Add unaccounted time to timeslice_used.

There are two kind of times that tasks are not charged for: the first
seek and the extra time slice used over the allocated timeslice. Both
of these exported as a new unaccounted_time stat.

I think it would be good to have this reported in 'time' as well, but
that is probably a separate discussion.

Signed-off-by: Justin TerAvest <teravest@google.com>
Signed-off-by: Jens Axboe <jaxboe@fusionio.com>

1 files changed, 15 insertions, 1 deletions

diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index 455768a3eb9e..77ee3c1ec1a7 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -371,12 +371,14 @@ void blkiocg_update_io_remove_stats(struct blkio_group *blkg,
 }
 EXPORT_SYMBOL_GPL(blkiocg_update_io_remove_stats);
 
-void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time)
+void blkiocg_update_timeslice_used(struct blkio_group *blkg, unsigned long time,
+                                unsigned long unaccounted_time)
 {
         unsigned long flags;
 
         spin_lock_irqsave(&blkg->stats_lock, flags);
         blkg->stats.time += time;
+        blkg->stats.unaccounted_time += unaccounted_time;
         spin_unlock_irqrestore(&blkg->stats_lock, flags);
 }
 EXPORT_SYMBOL_GPL(blkiocg_update_timeslice_used);
@@ -603,6 +605,9 @@ static uint64_t blkio_get_stat(struct blkio_group *blkg,
         if (type == BLKIO_STAT_SECTORS)
                 return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
                                         blkg->stats.sectors, cb, dev);
+        if (type == BLKIO_STAT_UNACCOUNTED_TIME)
+                return blkio_fill_stat(key_str, MAX_KEY_LEN - 1,
+                                        blkg->stats.unaccounted_time, cb, dev);
 #ifdef CONFIG_DEBUG_BLK_CGROUP
         if (type == BLKIO_STAT_AVG_QUEUE_SIZE) {
                 uint64_t sum = blkg->stats.avg_queue_size_sum;
@@ -1106,6 +1111,9 @@ static int blkiocg_file_read_map(struct cgroup *cgrp, struct cftype *cft,
                 case BLKIO_PROP_sectors:
                         return blkio_read_blkg_stats(blkcg, cft, cb,
                                                 BLKIO_STAT_SECTORS, 0);
+                case BLKIO_PROP_unaccounted_time:
+                        return blkio_read_blkg_stats(blkcg, cft, cb,
+                                                BLKIO_STAT_UNACCOUNTED_TIME, 0);
                 case BLKIO_PROP_io_service_bytes:
                         return blkio_read_blkg_stats(blkcg, cft, cb,
                                                 BLKIO_STAT_SERVICE_BYTES, 1);
@@ -1262,6 +1270,12 @@ struct cftype blkio_files[] = {
                 .read_map = blkiocg_file_read_map,
         },
         {
+                .name = "unaccounted_time",
+                .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
+                                BLKIO_PROP_unaccounted_time),
+                .read_map = blkiocg_file_read_map,
+        },
+        {
                 .name = "io_service_bytes",
                 .private = BLKIOFILE_PRIVATE(BLKIO_POLICY_PROP,
                                 BLKIO_PROP_io_service_bytes),