blkcg: move statistics update code to policies

As with conf/stats file handling code, there's no reason for stat
update code to live in blkcg core with policies calling into update
them.  The current organization is both inflexible and complex.

This patch moves stat update code to specific policies.  All
blkiocg_update_*_stats() functions which deal with BLKIO_POLICY_PROP
stats are collapsed into their cfq_blkiocg_update_*_stats()
counterparts.  blkiocg_update_dispatch_stats() is used by both
policies and duplicated as throtl_update_dispatch_stats() and
cfq_blkiocg_update_dispatch_stats().  This will be cleaned up later.

Signed-off-by: Tejun Heo <tj@kernel.org>

1 files changed, 30 insertions, 7 deletions

diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index fb6f25778fb2..5d647edc02a1 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -562,17 +562,42 @@ static bool tg_may_dispatch(struct throtl_data *td, struct throtl_grp *tg,
         return 0;
 }
 
+static void throtl_update_dispatch_stats(struct blkio_group *blkg, u64 bytes,
+                                         int rw)
+{
+        struct blkg_policy_data *pd = blkg->pd[BLKIO_POLICY_THROTL];
+        struct blkio_group_stats_cpu *stats_cpu;
+        unsigned long flags;
+
+        /* If per cpu stats are not allocated yet, don't do any accounting. */
+        if (pd->stats_cpu == NULL)
+                return;
+
+        /*
+         * Disabling interrupts to provide mutual exclusion between two
+         * writes on same cpu. It probably is not needed for 64bit. Not
+         * optimizing that case yet.
+         */
+        local_irq_save(flags);
+
+        stats_cpu = this_cpu_ptr(pd->stats_cpu);
+
+        blkg_stat_add(&stats_cpu->sectors, bytes >> 9);
+        blkg_rwstat_add(&stats_cpu->serviced, rw, 1);
+        blkg_rwstat_add(&stats_cpu->service_bytes, rw, bytes);
+
+        local_irq_restore(flags);
+}
+
 static void throtl_charge_bio(struct throtl_grp *tg, struct bio *bio)
 {
         bool rw = bio_data_dir(bio);
-        bool sync = rw_is_sync(bio->bi_rw);
 
         /* Charge the bio to the group */
         tg->bytes_disp[rw] += bio->bi_size;
         tg->io_disp[rw]++;
 
-        blkiocg_update_dispatch_stats(tg_to_blkg(tg), &blkio_policy_throtl,
-                                      bio->bi_size, rw, sync);
+        throtl_update_dispatch_stats(tg_to_blkg(tg), bio->bi_size, bio->bi_rw);
 }
 
 static void throtl_add_bio_tg(struct throtl_data *td, struct throtl_grp *tg,
@@ -1012,10 +1037,8 @@ bool blk_throtl_bio(struct request_queue *q, struct bio *bio)
         tg = throtl_lookup_tg(td, blkcg);
         if (tg) {
                 if (tg_no_rule_group(tg, rw)) {
-                        blkiocg_update_dispatch_stats(tg_to_blkg(tg),
-                                                      &blkio_policy_throtl,
-                                                      bio->bi_size, rw,
-                                                      rw_is_sync(bio->bi_rw));
+                        throtl_update_dispatch_stats(tg_to_blkg(tg),
+                                                     bio->bi_size, bio->bi_rw);
                         goto out_unlock_rcu;
                 }
         }