blkcg: move io_service_bytes and io_serviced stats into blkcg_gq
Currently, both cfq-iosched and blk-throttle keep track of
io_service_bytes and io_serviced stats. While keeping track of them
separately may be useful during development, it doesn't make much
sense otherwise. Also, blk-throttle was counting bio's as IOs while
cfq-iosched request's, which is more confusing than informative.
This patch adds ->stat_bytes and ->stat_ios to blkg (blkcg_gq),
removes the counterparts from cfq-iosched and blk-throttle and let
them print from the common blkg counters. The common counters are
incremented during bio issue in blkcg_bio_issue_check().
The outputs are still filtered by whether the policy has
blkg_policy_data on a given blkg, so cfq's output won't show up if it
has never been used for a given blkg. The only times when the outputs
would differ significantly are when policies are attached on the fly
or elevators are switched back and forth. Those are quite exceptional
operations and I don't think they warrant keeping separate counters.
v3: Update blkio-controller.txt accordingly.
v2: Account IOs during bio issues instead of request completions so
that bio-based drivers can be handled the same way.
Signed-off-by: Tejun Heo <tj@kernel.org>
Cc: Vivek Goyal <vgoyal@redhat.com>
Signed-off-by: Jens Axboe <axboe@fb.com>
diff --git a/Documentation/cgroups/blkio-controller.txt b/Documentation/cgroups/blkio-controller.txt
index 68b6a6a..12686be 100644
--- a/Documentation/cgroups/blkio-controller.txt
+++ b/Documentation/cgroups/blkio-controller.txt
@@ -201,7 +201,7 @@
specifies the number of bytes.
- blkio.io_serviced
- - Number of IOs completed to/from the disk by the group. These
+ - Number of IOs (bio) issued to the disk by the group. These
are further divided by the type of operation - read or write, sync
or async. First two fields specify the major and minor number of the
device, third field specifies the operation type and the fourth field
@@ -327,18 +327,11 @@
subjected to both the constraints.
- blkio.throttle.io_serviced
- - Number of IOs (bio) completed to/from the disk by the group (as
- seen by throttling policy). These are further divided by the type
- of operation - read or write, sync or async. First two fields specify
- the major and minor number of the device, third field specifies the
- operation type and the fourth field specifies the number of IOs.
-
- blkio.io_serviced does accounting as seen by CFQ and counts are in
- number of requests (struct request). On the other hand,
- blkio.throttle.io_serviced counts number of IO in terms of number
- of bios as seen by throttling policy. These bios can later be
- merged by elevator and total number of requests completed can be
- lesser.
+ - Number of IOs (bio) issued to the disk by the group. These
+ are further divided by the type of operation - read or write, sync
+ or async. First two fields specify the major and minor number of the
+ device, third field specifies the operation type and the fourth field
+ specifies the number of IOs.
- blkio.throttle.io_service_bytes
- Number of bytes transferred to/from the disk by the group. These
@@ -347,11 +340,6 @@
device, third field specifies the operation type and the fourth field
specifies the number of bytes.
- These numbers should roughly be same as blkio.io_service_bytes as
- updated by CFQ. The difference between two is that
- blkio.io_service_bytes will not be updated if CFQ is not operating
- on request queue.
-
Common files among various policies
-----------------------------------
- blkio.reset_stats
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index b263207..a25263c 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -73,6 +73,9 @@
if (blkg->blkcg != &blkcg_root)
blk_exit_rl(&blkg->rl);
+
+ blkg_rwstat_exit(&blkg->stat_ios);
+ blkg_rwstat_exit(&blkg->stat_bytes);
kfree(blkg);
}
@@ -95,6 +98,10 @@
if (!blkg)
return NULL;
+ if (blkg_rwstat_init(&blkg->stat_bytes, gfp_mask) ||
+ blkg_rwstat_init(&blkg->stat_ios, gfp_mask))
+ goto err_free;
+
blkg->q = q;
INIT_LIST_HEAD(&blkg->q_node);
blkg->blkcg = blkcg;
@@ -300,6 +307,7 @@
static void blkg_destroy(struct blkcg_gq *blkg)
{
struct blkcg *blkcg = blkg->blkcg;
+ struct blkcg_gq *parent = blkg->parent;
int i;
lockdep_assert_held(blkg->q->queue_lock);
@@ -315,6 +323,12 @@
if (blkg->pd[i] && pol->pd_offline_fn)
pol->pd_offline_fn(blkg->pd[i]);
}
+
+ if (parent) {
+ blkg_rwstat_add_aux(&parent->stat_bytes, &blkg->stat_bytes);
+ blkg_rwstat_add_aux(&parent->stat_ios, &blkg->stat_ios);
+ }
+
blkg->online = false;
radix_tree_delete(&blkcg->blkg_tree, blkg->q->id);
@@ -431,6 +445,9 @@
* anyway. If you get hit by a race, retry.
*/
hlist_for_each_entry(blkg, &blkcg->blkg_list, blkcg_node) {
+ blkg_rwstat_reset(&blkg->stat_bytes);
+ blkg_rwstat_reset(&blkg->stat_ios);
+
for (i = 0; i < BLKCG_MAX_POLS; i++) {
struct blkcg_policy *pol = blkcg_policy[i];
@@ -579,6 +596,87 @@
}
EXPORT_SYMBOL_GPL(blkg_prfill_rwstat);
+static u64 blkg_prfill_rwstat_field(struct seq_file *sf,
+ struct blkg_policy_data *pd, int off)
+{
+ struct blkg_rwstat rwstat = blkg_rwstat_read((void *)pd->blkg + off);
+
+ return __blkg_prfill_rwstat(sf, pd, &rwstat);
+}
+
+/**
+ * blkg_print_stat_bytes - seq_show callback for blkg->stat_bytes
+ * @sf: seq_file to print to
+ * @v: unused
+ *
+ * To be used as cftype->seq_show to print blkg->stat_bytes.
+ * cftype->private must be set to the blkcg_policy.
+ */
+int blkg_print_stat_bytes(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ blkg_prfill_rwstat_field, (void *)seq_cft(sf)->private,
+ offsetof(struct blkcg_gq, stat_bytes), true);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blkg_print_stat_bytes);
+
+/**
+ * blkg_print_stat_bytes - seq_show callback for blkg->stat_ios
+ * @sf: seq_file to print to
+ * @v: unused
+ *
+ * To be used as cftype->seq_show to print blkg->stat_ios. cftype->private
+ * must be set to the blkcg_policy.
+ */
+int blkg_print_stat_ios(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ blkg_prfill_rwstat_field, (void *)seq_cft(sf)->private,
+ offsetof(struct blkcg_gq, stat_ios), true);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blkg_print_stat_ios);
+
+static u64 blkg_prfill_rwstat_field_recursive(struct seq_file *sf,
+ struct blkg_policy_data *pd,
+ int off)
+{
+ struct blkg_rwstat rwstat = blkg_rwstat_recursive_sum(pd->blkg,
+ NULL, off);
+ return __blkg_prfill_rwstat(sf, pd, &rwstat);
+}
+
+/**
+ * blkg_print_stat_bytes_recursive - recursive version of blkg_print_stat_bytes
+ * @sf: seq_file to print to
+ * @v: unused
+ */
+int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ blkg_prfill_rwstat_field_recursive,
+ (void *)seq_cft(sf)->private,
+ offsetof(struct blkcg_gq, stat_bytes), true);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blkg_print_stat_bytes_recursive);
+
+/**
+ * blkg_print_stat_ios_recursive - recursive version of blkg_print_stat_ios
+ * @sf: seq_file to print to
+ * @v: unused
+ */
+int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v)
+{
+ blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)),
+ blkg_prfill_rwstat_field_recursive,
+ (void *)seq_cft(sf)->private,
+ offsetof(struct blkcg_gq, stat_ios), true);
+ return 0;
+}
+EXPORT_SYMBOL_GPL(blkg_print_stat_ios_recursive);
+
/**
* blkg_stat_recursive_sum - collect hierarchical blkg_stat
* @blkg: blkg of interest
diff --git a/block/blk-throttle.c b/block/blk-throttle.c
index c0b2263..bd3e4b2 100644
--- a/block/blk-throttle.c
+++ b/block/blk-throttle.c
@@ -133,11 +133,6 @@
/* When did we start a new slice */
unsigned long slice_start[2];
unsigned long slice_end[2];
-
- /* total bytes transferred */
- struct blkg_rwstat service_bytes;
- /* total IOs serviced, post merge */
- struct blkg_rwstat serviced;
};
struct throtl_data
@@ -335,11 +330,7 @@
tg = kzalloc_node(sizeof(*tg), gfp, node);
if (!tg)
- goto err;
-
- if (blkg_rwstat_init(&tg->service_bytes, gfp) ||
- blkg_rwstat_init(&tg->serviced, gfp))
- goto err_free_tg;
+ return NULL;
throtl_service_queue_init(&tg->service_queue);
@@ -355,13 +346,6 @@
tg->iops[WRITE] = -1;
return &tg->pd;
-
-err_free_tg:
- blkg_rwstat_exit(&tg->serviced);
- blkg_rwstat_exit(&tg->service_bytes);
- kfree(tg);
-err:
- return NULL;
}
static void throtl_pd_init(struct blkg_policy_data *pd)
@@ -419,19 +403,9 @@
struct throtl_grp *tg = pd_to_tg(pd);
del_timer_sync(&tg->service_queue.pending_timer);
- blkg_rwstat_exit(&tg->serviced);
- blkg_rwstat_exit(&tg->service_bytes);
kfree(tg);
}
-static void throtl_pd_reset_stats(struct blkg_policy_data *pd)
-{
- struct throtl_grp *tg = pd_to_tg(pd);
-
- blkg_rwstat_reset(&tg->service_bytes);
- blkg_rwstat_reset(&tg->serviced);
-}
-
static struct throtl_grp *
throtl_rb_first(struct throtl_service_queue *parent_sq)
{
@@ -839,25 +813,6 @@
return 0;
}
-static void throtl_update_dispatch_stats(struct blkcg_gq *blkg, u64 bytes,
- int rw)
-{
- struct throtl_grp *tg = blkg_to_tg(blkg);
- unsigned long flags;
-
- /*
- * 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);
-
- blkg_rwstat_add(&tg->serviced, rw, 1);
- blkg_rwstat_add(&tg->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);
@@ -871,17 +826,9 @@
* more than once as a throttled bio will go through blk-throtl the
* second time when it eventually gets issued. Set it when a bio
* is being charged to a tg.
- *
- * Dispatch stats aren't recursive and each @bio should only be
- * accounted by the @tg it was originally associated with. Let's
- * update the stats when setting REQ_THROTTLED for the first time
- * which is guaranteed to be for the @bio's original tg.
*/
- if (!(bio->bi_rw & REQ_THROTTLED)) {
+ if (!(bio->bi_rw & REQ_THROTTLED))
bio->bi_rw |= REQ_THROTTLED;
- throtl_update_dispatch_stats(tg_to_blkg(tg),
- bio->bi_iter.bi_size, bio->bi_rw);
- }
}
/**
@@ -1161,13 +1108,6 @@
}
}
-static int tg_print_rwstat(struct seq_file *sf, void *v)
-{
- blkcg_print_blkgs(sf, css_to_blkcg(seq_css(sf)), blkg_prfill_rwstat,
- &blkcg_policy_throtl, seq_cft(sf)->private, true);
- return 0;
-}
-
static u64 tg_prfill_conf_u64(struct seq_file *sf, struct blkg_policy_data *pd,
int off)
{
@@ -1304,13 +1244,13 @@
},
{
.name = "throttle.io_service_bytes",
- .private = offsetof(struct throtl_grp, service_bytes),
- .seq_show = tg_print_rwstat,
+ .private = (unsigned long)&blkcg_policy_throtl,
+ .seq_show = blkg_print_stat_bytes,
},
{
.name = "throttle.io_serviced",
- .private = offsetof(struct throtl_grp, serviced),
- .seq_show = tg_print_rwstat,
+ .private = (unsigned long)&blkcg_policy_throtl,
+ .seq_show = blkg_print_stat_ios,
},
{ } /* terminate */
};
@@ -1329,7 +1269,6 @@
.pd_init_fn = throtl_pd_init,
.pd_online_fn = throtl_pd_online,
.pd_free_fn = throtl_pd_free,
- .pd_reset_stats_fn = throtl_pd_reset_stats,
};
bool blk_throtl_bio(struct request_queue *q, struct blkcg_gq *blkg,
diff --git a/block/cfq-iosched.c b/block/cfq-iosched.c
index e861cc1..a948d4d 100644
--- a/block/cfq-iosched.c
+++ b/block/cfq-iosched.c
@@ -177,10 +177,6 @@
struct cfqg_stats {
#ifdef CONFIG_CFQ_GROUP_IOSCHED
- /* total bytes transferred */
- struct blkg_rwstat service_bytes;
- /* total IOs serviced, post merge */
- struct blkg_rwstat serviced;
/* number of ios merged */
struct blkg_rwstat merged;
/* total time spent on device in ns, may not be accurate w/ queueing */
@@ -696,8 +692,6 @@
uint64_t bytes, int rw)
{
blkg_stat_add(&cfqg->stats.sectors, bytes >> 9);
- blkg_rwstat_add(&cfqg->stats.serviced, rw, 1);
- blkg_rwstat_add(&cfqg->stats.service_bytes, rw, bytes);
}
static inline void cfqg_stats_update_completion(struct cfq_group *cfqg,
@@ -717,8 +711,6 @@
static void cfqg_stats_reset(struct cfqg_stats *stats)
{
/* queued stats shouldn't be cleared */
- blkg_rwstat_reset(&stats->service_bytes);
- blkg_rwstat_reset(&stats->serviced);
blkg_rwstat_reset(&stats->merged);
blkg_rwstat_reset(&stats->service_time);
blkg_rwstat_reset(&stats->wait_time);
@@ -738,8 +730,6 @@
static void cfqg_stats_add_aux(struct cfqg_stats *to, struct cfqg_stats *from)
{
/* queued stats shouldn't be cleared */
- blkg_rwstat_add_aux(&to->service_bytes, &from->service_bytes);
- blkg_rwstat_add_aux(&to->serviced, &from->serviced);
blkg_rwstat_add_aux(&to->merged, &from->merged);
blkg_rwstat_add_aux(&to->service_time, &from->service_time);
blkg_rwstat_add_aux(&to->wait_time, &from->wait_time);
@@ -1544,8 +1534,6 @@
#ifdef CONFIG_CFQ_GROUP_IOSCHED
static void cfqg_stats_exit(struct cfqg_stats *stats)
{
- blkg_rwstat_exit(&stats->service_bytes);
- blkg_rwstat_exit(&stats->serviced);
blkg_rwstat_exit(&stats->merged);
blkg_rwstat_exit(&stats->service_time);
blkg_rwstat_exit(&stats->wait_time);
@@ -1566,9 +1554,7 @@
static int cfqg_stats_init(struct cfqg_stats *stats, gfp_t gfp)
{
- if (blkg_rwstat_init(&stats->service_bytes, gfp) ||
- blkg_rwstat_init(&stats->serviced, gfp) ||
- blkg_rwstat_init(&stats->merged, gfp) ||
+ if (blkg_rwstat_init(&stats->merged, gfp) ||
blkg_rwstat_init(&stats->service_time, gfp) ||
blkg_rwstat_init(&stats->wait_time, gfp) ||
blkg_rwstat_init(&stats->queued, gfp) ||
@@ -1994,13 +1980,13 @@
},
{
.name = "io_service_bytes",
- .private = offsetof(struct cfq_group, stats.service_bytes),
- .seq_show = cfqg_print_rwstat,
+ .private = (unsigned long)&blkcg_policy_cfq,
+ .seq_show = blkg_print_stat_bytes,
},
{
.name = "io_serviced",
- .private = offsetof(struct cfq_group, stats.serviced),
- .seq_show = cfqg_print_rwstat,
+ .private = (unsigned long)&blkcg_policy_cfq,
+ .seq_show = blkg_print_stat_ios,
},
{
.name = "io_service_time",
@@ -2036,13 +2022,13 @@
},
{
.name = "io_service_bytes_recursive",
- .private = offsetof(struct cfq_group, stats.service_bytes),
- .seq_show = cfqg_print_rwstat_recursive,
+ .private = (unsigned long)&blkcg_policy_cfq,
+ .seq_show = blkg_print_stat_bytes_recursive,
},
{
.name = "io_serviced_recursive",
- .private = offsetof(struct cfq_group, stats.serviced),
- .seq_show = cfqg_print_rwstat_recursive,
+ .private = (unsigned long)&blkcg_policy_cfq,
+ .seq_show = blkg_print_stat_ios_recursive,
},
{
.name = "io_service_time_recursive",
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index 4630ce8..286e1bd 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -127,6 +127,9 @@
/* is this blkg online? protected by both blkcg and q locks */
bool online;
+ struct blkg_rwstat stat_bytes;
+ struct blkg_rwstat stat_ios;
+
struct blkg_policy_data *pd[BLKCG_MAX_POLS];
struct rcu_head rcu_head;
@@ -190,6 +193,10 @@
u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off);
u64 blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
int off);
+int blkg_print_stat_bytes(struct seq_file *sf, void *v);
+int blkg_print_stat_ios(struct seq_file *sf, void *v);
+int blkg_print_stat_bytes_recursive(struct seq_file *sf, void *v);
+int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v);
u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
struct blkcg_policy *pol, int off);
@@ -700,6 +707,13 @@
throtl = blk_throtl_bio(q, blkg, bio);
+ if (!throtl) {
+ blkg = blkg ?: q->root_blkg;
+ blkg_rwstat_add(&blkg->stat_bytes, bio->bi_flags,
+ bio->bi_iter.bi_size);
+ blkg_rwstat_add(&blkg->stat_ios, bio->bi_flags, 1);
+ }
+
rcu_read_unlock();
return !throtl;
}
