cfq-iosched: add hierarchical cfq_group statistics
Tejun Heo [Wed, 9 Jan 2013 16:05:13 +0000 (08:05 -0800)]
Unfortunately, at this point, there's no way to make the existing
statistics hierarchical without creating nasty surprises for the
existing users.  Just create recursive counterpart of the existing
stats.

Signed-off-by: Tejun Heo <tj@kernel.org>
Acked-by: Vivek Goyal <vgoyal@redhat.com>

block/cfq-iosched.c

index 4d75b79..b66365b 100644 (file)
@@ -1528,6 +1528,32 @@ static void cfq_pd_offline(struct blkcg_gq *blkg)
        cfqg_stats_xfer_dead(blkg_to_cfqg(blkg));
 }
 
+/* offset delta from cfqg->stats to cfqg->dead_stats */
+static const int dead_stats_off_delta = offsetof(struct cfq_group, dead_stats) -
+                                       offsetof(struct cfq_group, stats);
+
+/* to be used by recursive prfill, sums live and dead stats recursively */
+static u64 cfqg_stat_pd_recursive_sum(struct blkg_policy_data *pd, int off)
+{
+       u64 sum = 0;
+
+       sum += blkg_stat_recursive_sum(pd, off);
+       sum += blkg_stat_recursive_sum(pd, off + dead_stats_off_delta);
+       return sum;
+}
+
+/* to be used by recursive prfill, sums live and dead rwstats recursively */
+static struct blkg_rwstat cfqg_rwstat_pd_recursive_sum(struct blkg_policy_data *pd,
+                                                      int off)
+{
+       struct blkg_rwstat a, b;
+
+       a = blkg_rwstat_recursive_sum(pd, off);
+       b = blkg_rwstat_recursive_sum(pd, off + dead_stats_off_delta);
+       blkg_rwstat_merge(&a, &b);
+       return a;
+}
+
 static void cfq_pd_reset_stats(struct blkcg_gq *blkg)
 {
        struct cfq_group *cfqg = blkg_to_cfqg(blkg);
@@ -1732,6 +1758,42 @@ static int cfqg_print_rwstat(struct cgroup *cgrp, struct cftype *cft,
        return 0;
 }
 
+static u64 cfqg_prfill_stat_recursive(struct seq_file *sf,
+                                     struct blkg_policy_data *pd, int off)
+{
+       u64 sum = cfqg_stat_pd_recursive_sum(pd, off);
+
+       return __blkg_prfill_u64(sf, pd, sum);
+}
+
+static u64 cfqg_prfill_rwstat_recursive(struct seq_file *sf,
+                                       struct blkg_policy_data *pd, int off)
+{
+       struct blkg_rwstat sum = cfqg_rwstat_pd_recursive_sum(pd, off);
+
+       return __blkg_prfill_rwstat(sf, pd, &sum);
+}
+
+static int cfqg_print_stat_recursive(struct cgroup *cgrp, struct cftype *cft,
+                                    struct seq_file *sf)
+{
+       struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
+
+       blkcg_print_blkgs(sf, blkcg, cfqg_prfill_stat_recursive,
+                         &blkcg_policy_cfq, cft->private, false);
+       return 0;
+}
+
+static int cfqg_print_rwstat_recursive(struct cgroup *cgrp, struct cftype *cft,
+                                      struct seq_file *sf)
+{
+       struct blkcg *blkcg = cgroup_to_blkcg(cgrp);
+
+       blkcg_print_blkgs(sf, blkcg, cfqg_prfill_rwstat_recursive,
+                         &blkcg_policy_cfq, cft->private, true);
+       return 0;
+}
+
 #ifdef CONFIG_DEBUG_BLK_CGROUP
 static u64 cfqg_prfill_avg_queue_size(struct seq_file *sf,
                                      struct blkg_policy_data *pd, int off)
@@ -1803,6 +1865,7 @@ static struct cftype cfq_blkcg_files[] = {
                .write_u64 = cfq_set_leaf_weight,
        },
 
+       /* statistics, covers only the tasks in the cfqg */
        {
                .name = "time",
                .private = offsetof(struct cfq_group, stats.time),
@@ -1843,6 +1906,48 @@ static struct cftype cfq_blkcg_files[] = {
                .private = offsetof(struct cfq_group, stats.queued),
                .read_seq_string = cfqg_print_rwstat,
        },
+
+       /* the same statictics which cover the cfqg and its descendants */
+       {
+               .name = "time_recursive",
+               .private = offsetof(struct cfq_group, stats.time),
+               .read_seq_string = cfqg_print_stat_recursive,
+       },
+       {
+               .name = "sectors_recursive",
+               .private = offsetof(struct cfq_group, stats.sectors),
+               .read_seq_string = cfqg_print_stat_recursive,
+       },
+       {
+               .name = "io_service_bytes_recursive",
+               .private = offsetof(struct cfq_group, stats.service_bytes),
+               .read_seq_string = cfqg_print_rwstat_recursive,
+       },
+       {
+               .name = "io_serviced_recursive",
+               .private = offsetof(struct cfq_group, stats.serviced),
+               .read_seq_string = cfqg_print_rwstat_recursive,
+       },
+       {
+               .name = "io_service_time_recursive",
+               .private = offsetof(struct cfq_group, stats.service_time),
+               .read_seq_string = cfqg_print_rwstat_recursive,
+       },
+       {
+               .name = "io_wait_time_recursive",
+               .private = offsetof(struct cfq_group, stats.wait_time),
+               .read_seq_string = cfqg_print_rwstat_recursive,
+       },
+       {
+               .name = "io_merged_recursive",
+               .private = offsetof(struct cfq_group, stats.merged),
+               .read_seq_string = cfqg_print_rwstat_recursive,
+       },
+       {
+               .name = "io_queued_recursive",
+               .private = offsetof(struct cfq_group, stats.queued),
+               .read_seq_string = cfqg_print_rwstat_recursive,
+       },
 #ifdef CONFIG_DEBUG_BLK_CGROUP
        {
                .name = "avg_queue_size",