[PATCH 4/6] blk-cgroup: move struct blkg_stat to bfq

From: Christoph Hellwig
Date: Thu Jun 06 2019 - 06:30:49 EST

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In reply to: Christoph Hellwig: "[PATCH 3/6] blk-cgroup: introduce a new struct blkg_rwstat_sample"
Next in thread: Paolo Valente: "Re: [PATCH 4/6] blk-cgroup: move struct blkg_stat to bfq"
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This structure and assorted infrastructure is only used by the bfq I/O
scheduler. Move it there instead of bloating the common code.

Signed-off-by: Christoph Hellwig <hch@xxxxxx>
---
block/bfq-cgroup.c | 192 ++++++++++++++++++++++++++++++-------
block/bfq-iosched.h | 19 ++--
block/blk-cgroup.c | 56 -----------
include/linux/blk-cgroup.h | 71 --------------
4 files changed, 167 insertions(+), 171 deletions(-)

diff --git a/block/bfq-cgroup.c b/block/bfq-cgroup.c
index 624374a99c6e..a691dca7e966 100644
--- a/block/bfq-cgroup.c
+++ b/block/bfq-cgroup.c
@@ -17,6 +17,124 @@

#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)

+static int bfq_stat_init(struct bfq_stat *stat, gfp_t gfp)
+{
+ int ret;
+
+ ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
+ if (ret)
+ return ret;
+
+ atomic64_set(&stat->aux_cnt, 0);
+ return 0;
+}
+
+static void bfq_stat_exit(struct bfq_stat *stat)
+{
+ percpu_counter_destroy(&stat->cpu_cnt);
+}
+
+/**
+ * bfq_stat_add - add a value to a bfq_stat
+ * @stat: target bfq_stat
+ * @val: value to add
+ *
+ * Add @val to @stat. The caller must ensure that IRQ on the same CPU
+ * don't re-enter this function for the same counter.
+ */
+static inline void bfq_stat_add(struct bfq_stat *stat, uint64_t val)
+{
+ percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
+}
+
+/**
+ * bfq_stat_read - read the current value of a bfq_stat
+ * @stat: bfq_stat to read
+ */
+static inline uint64_t bfq_stat_read(struct bfq_stat *stat)
+{
+ return percpu_counter_sum_positive(&stat->cpu_cnt);
+}
+
+/**
+ * bfq_stat_reset - reset a bfq_stat
+ * @stat: bfq_stat to reset
+ */
+static inline void bfq_stat_reset(struct bfq_stat *stat)
+{
+ percpu_counter_set(&stat->cpu_cnt, 0);
+ atomic64_set(&stat->aux_cnt, 0);
+}
+
+/**
+ * bfq_stat_add_aux - add a bfq_stat into another's aux count
+ * @to: the destination bfq_stat
+ * @from: the source
+ *
+ * Add @from's count including the aux one to @to's aux count.
+ */
+static inline void bfq_stat_add_aux(struct bfq_stat *to,
+ struct bfq_stat *from)
+{
+ atomic64_add(bfq_stat_read(from) + atomic64_read(&from->aux_cnt),
+ &to->aux_cnt);
+}
+
+/**
+ * bfq_stat_recursive_sum - collect hierarchical bfq_stat
+ * @blkg: blkg of interest
+ * @pol: blkcg_policy which contains the bfq_stat
+ * @off: offset to the bfq_stat in blkg_policy_data or @blkg
+ *
+ * Collect the bfq_stat specified by @blkg, @pol and @off and all its
+ * online descendants and their aux counts. The caller must be holding the
+ * queue lock for online tests.
+ *
+ * If @pol is NULL, bfq_stat is at @off bytes into @blkg; otherwise, it is
+ * at @off bytes into @blkg's blkg_policy_data of the policy.
+ */
+static u64 bfq_stat_recursive_sum(struct blkcg_gq *blkg,
+ struct blkcg_policy *pol, int off)
+{
+ struct blkcg_gq *pos_blkg;
+ struct cgroup_subsys_state *pos_css;
+ u64 sum = 0;
+
+ lockdep_assert_held(&blkg->q->queue_lock);
+
+ rcu_read_lock();
+ blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
+ struct bfq_stat *stat;
+
+ if (!pos_blkg->online)
+ continue;
+
+ if (pol)
+ stat = (void *)blkg_to_pd(pos_blkg, pol) + off;
+ else
+ stat = (void *)blkg + off;
+
+ sum += bfq_stat_read(stat) + atomic64_read(&stat->aux_cnt);
+ }
+ rcu_read_unlock();
+
+ return sum;
+}
+
+/**
+ * blkg_prfill_stat - prfill callback for bfq_stat
+ * @sf: seq_file to print to
+ * @pd: policy private data of interest
+ * @off: offset to the bfq_stat in @pd
+ *
+ * prfill callback for printing a bfq_stat.
+ */
+static u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd,
+ int off)
+{
+ return __blkg_prfill_u64(sf, pd, bfq_stat_read((void *)pd + off));
+}
+
/* bfqg stats flags */
enum bfqg_stats_flags {
BFQG_stats_waiting = 0,
@@ -53,7 +171,7 @@ static void bfqg_stats_update_group_wait_time(struct bfqg_stats *stats)

now = ktime_get_ns();
if (now > stats->start_group_wait_time)
- blkg_stat_add(&stats->group_wait_time,
+ bfq_stat_add(&stats->group_wait_time,
now - stats->start_group_wait_time);
bfqg_stats_clear_waiting(stats);
}
@@ -82,14 +200,14 @@ static void bfqg_stats_end_empty_time(struct bfqg_stats *stats)

now = ktime_get_ns();
if (now > stats->start_empty_time)
- blkg_stat_add(&stats->empty_time,
+ bfq_stat_add(&stats->empty_time,
now - stats->start_empty_time);
bfqg_stats_clear_empty(stats);
}

void bfqg_stats_update_dequeue(struct bfq_group *bfqg)
{
- blkg_stat_add(&bfqg->stats.dequeue, 1);
+ bfq_stat_add(&bfqg->stats.dequeue, 1);
}

void bfqg_stats_set_start_empty_time(struct bfq_group *bfqg)
@@ -119,7 +237,7 @@ void bfqg_stats_update_idle_time(struct bfq_group *bfqg)
u64 now = ktime_get_ns();

if (now > stats->start_idle_time)
- blkg_stat_add(&stats->idle_time,
+ bfq_stat_add(&stats->idle_time,
now - stats->start_idle_time);
bfqg_stats_clear_idling(stats);
}
@@ -137,9 +255,9 @@ void bfqg_stats_update_avg_queue_size(struct bfq_group *bfqg)
{
struct bfqg_stats *stats = &bfqg->stats;

- blkg_stat_add(&stats->avg_queue_size_sum,
+ bfq_stat_add(&stats->avg_queue_size_sum,
blkg_rwstat_total(&stats->queued));
- blkg_stat_add(&stats->avg_queue_size_samples, 1);
+ bfq_stat_add(&stats->avg_queue_size_samples, 1);
bfqg_stats_update_group_wait_time(stats);
}

@@ -279,13 +397,13 @@ static void bfqg_stats_reset(struct bfqg_stats *stats)
blkg_rwstat_reset(&stats->merged);
blkg_rwstat_reset(&stats->service_time);
blkg_rwstat_reset(&stats->wait_time);
- blkg_stat_reset(&stats->time);
- blkg_stat_reset(&stats->avg_queue_size_sum);
- blkg_stat_reset(&stats->avg_queue_size_samples);
- blkg_stat_reset(&stats->dequeue);
- blkg_stat_reset(&stats->group_wait_time);
- blkg_stat_reset(&stats->idle_time);
- blkg_stat_reset(&stats->empty_time);
+ bfq_stat_reset(&stats->time);
+ bfq_stat_reset(&stats->avg_queue_size_sum);
+ bfq_stat_reset(&stats->avg_queue_size_samples);
+ bfq_stat_reset(&stats->dequeue);
+ bfq_stat_reset(&stats->group_wait_time);
+ bfq_stat_reset(&stats->idle_time);
+ bfq_stat_reset(&stats->empty_time);
#endif
}

@@ -300,14 +418,14 @@ static void bfqg_stats_add_aux(struct bfqg_stats *to, struct bfqg_stats *from)
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);
- blkg_stat_add_aux(&from->time, &from->time);
- blkg_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
- blkg_stat_add_aux(&to->avg_queue_size_samples,
+ bfq_stat_add_aux(&from->time, &from->time);
+ bfq_stat_add_aux(&to->avg_queue_size_sum, &from->avg_queue_size_sum);
+ bfq_stat_add_aux(&to->avg_queue_size_samples,
&from->avg_queue_size_samples);
- blkg_stat_add_aux(&to->dequeue, &from->dequeue);
- blkg_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
- blkg_stat_add_aux(&to->idle_time, &from->idle_time);
- blkg_stat_add_aux(&to->empty_time, &from->empty_time);
+ bfq_stat_add_aux(&to->dequeue, &from->dequeue);
+ bfq_stat_add_aux(&to->group_wait_time, &from->group_wait_time);
+ bfq_stat_add_aux(&to->idle_time, &from->idle_time);
+ bfq_stat_add_aux(&to->empty_time, &from->empty_time);
#endif
}

@@ -360,13 +478,13 @@ static void bfqg_stats_exit(struct bfqg_stats *stats)
blkg_rwstat_exit(&stats->service_time);
blkg_rwstat_exit(&stats->wait_time);
blkg_rwstat_exit(&stats->queued);
- blkg_stat_exit(&stats->time);
- blkg_stat_exit(&stats->avg_queue_size_sum);
- blkg_stat_exit(&stats->avg_queue_size_samples);
- blkg_stat_exit(&stats->dequeue);
- blkg_stat_exit(&stats->group_wait_time);
- blkg_stat_exit(&stats->idle_time);
- blkg_stat_exit(&stats->empty_time);
+ bfq_stat_exit(&stats->time);
+ bfq_stat_exit(&stats->avg_queue_size_sum);
+ bfq_stat_exit(&stats->avg_queue_size_samples);
+ bfq_stat_exit(&stats->dequeue);
+ bfq_stat_exit(&stats->group_wait_time);
+ bfq_stat_exit(&stats->idle_time);
+ bfq_stat_exit(&stats->empty_time);
#endif
}

@@ -377,13 +495,13 @@ static int bfqg_stats_init(struct bfqg_stats *stats, gfp_t gfp)
blkg_rwstat_init(&stats->service_time, gfp) ||
blkg_rwstat_init(&stats->wait_time, gfp) ||
blkg_rwstat_init(&stats->queued, gfp) ||
- blkg_stat_init(&stats->time, gfp) ||
- blkg_stat_init(&stats->avg_queue_size_sum, gfp) ||
- blkg_stat_init(&stats->avg_queue_size_samples, gfp) ||
- blkg_stat_init(&stats->dequeue, gfp) ||
- blkg_stat_init(&stats->group_wait_time, gfp) ||
- blkg_stat_init(&stats->idle_time, gfp) ||
- blkg_stat_init(&stats->empty_time, gfp)) {
+ bfq_stat_init(&stats->time, gfp) ||
+ bfq_stat_init(&stats->avg_queue_size_sum, gfp) ||
+ bfq_stat_init(&stats->avg_queue_size_samples, gfp) ||
+ bfq_stat_init(&stats->dequeue, gfp) ||
+ bfq_stat_init(&stats->group_wait_time, gfp) ||
+ bfq_stat_init(&stats->idle_time, gfp) ||
+ bfq_stat_init(&stats->empty_time, gfp)) {
bfqg_stats_exit(stats);
return -ENOMEM;
}
@@ -927,7 +1045,7 @@ static int bfqg_print_rwstat(struct seq_file *sf, void *v)
static u64 bfqg_prfill_stat_recursive(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
- u64 sum = blkg_stat_recursive_sum(pd_to_blkg(pd),
+ u64 sum = bfq_stat_recursive_sum(pd_to_blkg(pd),
&blkcg_policy_bfq, off);
return __blkg_prfill_u64(sf, pd, sum);
}
@@ -996,11 +1114,11 @@ static u64 bfqg_prfill_avg_queue_size(struct seq_file *sf,
struct blkg_policy_data *pd, int off)
{
struct bfq_group *bfqg = pd_to_bfqg(pd);
- u64 samples = blkg_stat_read(&bfqg->stats.avg_queue_size_samples);
+ u64 samples = bfq_stat_read(&bfqg->stats.avg_queue_size_samples);
u64 v = 0;

if (samples) {
- v = blkg_stat_read(&bfqg->stats.avg_queue_size_sum);
+ v = bfq_stat_read(&bfqg->stats.avg_queue_size_sum);
v = div64_u64(v, samples);
}
__blkg_prfill_u64(sf, pd, v);
diff --git a/block/bfq-iosched.h b/block/bfq-iosched.h
index c2faa77824f8..aef4fa0046b8 100644
--- a/block/bfq-iosched.h
+++ b/block/bfq-iosched.h
@@ -777,6 +777,11 @@ enum bfqq_expiration {
BFQQE_PREEMPTED /* preemption in progress */
};

+struct bfq_stat {
+ struct percpu_counter cpu_cnt;
+ atomic64_t aux_cnt;
+};
+
struct bfqg_stats {
#if defined(CONFIG_BFQ_GROUP_IOSCHED) && defined(CONFIG_DEBUG_BLK_CGROUP)
/* number of ios merged */
@@ -788,19 +793,19 @@ struct bfqg_stats {
/* number of IOs queued up */
struct blkg_rwstat queued;
/* total disk time and nr sectors dispatched by this group */
- struct blkg_stat time;
+ struct bfq_stat time;
/* sum of number of ios queued across all samples */
- struct blkg_stat avg_queue_size_sum;
+ struct bfq_stat avg_queue_size_sum;
/* count of samples taken for average */
- struct blkg_stat avg_queue_size_samples;
+ struct bfq_stat avg_queue_size_samples;
/* how many times this group has been removed from service tree */
- struct blkg_stat dequeue;
+ struct bfq_stat dequeue;
/* total time spent waiting for it to be assigned a timeslice. */
- struct blkg_stat group_wait_time;
+ struct bfq_stat group_wait_time;
/* time spent idling for this blkcg_gq */
- struct blkg_stat idle_time;
+ struct bfq_stat idle_time;
/* total time with empty current active q with other requests queued */
- struct blkg_stat empty_time;
+ struct bfq_stat empty_time;
/* fields after this shouldn't be cleared on stat reset */
u64 start_group_wait_time;
u64 start_idle_time;
diff --git a/block/blk-cgroup.c b/block/blk-cgroup.c
index aad0f5d9a2ea..1aa5c64675d6 100644
--- a/block/blk-cgroup.c
+++ b/block/blk-cgroup.c
@@ -577,20 +577,6 @@ u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
}
EXPORT_SYMBOL_GPL(__blkg_prfill_rwstat);

-/**
- * blkg_prfill_stat - prfill callback for blkg_stat
- * @sf: seq_file to print to
- * @pd: policy private data of interest
- * @off: offset to the blkg_stat in @pd
- *
- * prfill callback for printing a blkg_stat.
- */
-u64 blkg_prfill_stat(struct seq_file *sf, struct blkg_policy_data *pd, int off)
-{
- return __blkg_prfill_u64(sf, pd, blkg_stat_read((void *)pd + off));
-}
-EXPORT_SYMBOL_GPL(blkg_prfill_stat);
-
/**
* blkg_prfill_rwstat - prfill callback for blkg_rwstat
* @sf: seq_file to print to
@@ -692,48 +678,6 @@ int blkg_print_stat_ios_recursive(struct seq_file *sf, void *v)
}
EXPORT_SYMBOL_GPL(blkg_print_stat_ios_recursive);

-/**
- * blkg_stat_recursive_sum - collect hierarchical blkg_stat
- * @blkg: blkg of interest
- * @pol: blkcg_policy which contains the blkg_stat
- * @off: offset to the blkg_stat in blkg_policy_data or @blkg
- *
- * Collect the blkg_stat specified by @blkg, @pol and @off and all its
- * online descendants and their aux counts. The caller must be holding the
- * queue lock for online tests.
- *
- * If @pol is NULL, blkg_stat is at @off bytes into @blkg; otherwise, it is
- * at @off bytes into @blkg's blkg_policy_data of the policy.
- */
-u64 blkg_stat_recursive_sum(struct blkcg_gq *blkg,
- struct blkcg_policy *pol, int off)
-{
- struct blkcg_gq *pos_blkg;
- struct cgroup_subsys_state *pos_css;
- u64 sum = 0;
-
- lockdep_assert_held(&blkg->q->queue_lock);
-
- rcu_read_lock();
- blkg_for_each_descendant_pre(pos_blkg, pos_css, blkg) {
- struct blkg_stat *stat;
-
- if (!pos_blkg->online)
- continue;
-
- if (pol)
- stat = (void *)blkg_to_pd(pos_blkg, pol) + off;
- else
- stat = (void *)blkg + off;
-
- sum += blkg_stat_read(stat) + atomic64_read(&stat->aux_cnt);
- }
- rcu_read_unlock();
-
- return sum;
-}
-EXPORT_SYMBOL_GPL(blkg_stat_recursive_sum);
-
/**
* blkg_rwstat_recursive_sum - collect hierarchical blkg_rwstat
* @blkg: blkg of interest
diff --git a/include/linux/blk-cgroup.h b/include/linux/blk-cgroup.h
index e4a81767e111..33f23a858438 100644
--- a/include/linux/blk-cgroup.h
+++ b/include/linux/blk-cgroup.h
@@ -65,11 +65,6 @@ struct blkcg {
* blkg_[rw]stat->aux_cnt is excluded for local stats but included for
* recursive. Used to carry stats of dead children.
*/
-struct blkg_stat {
- struct percpu_counter cpu_cnt;
- atomic64_t aux_cnt;
-};
-
struct blkg_rwstat {
struct percpu_counter cpu_cnt[BLKG_RWSTAT_NR];
atomic64_t aux_cnt[BLKG_RWSTAT_NR];
@@ -217,7 +212,6 @@ void blkcg_print_blkgs(struct seq_file *sf, struct blkcg *blkcg,
u64 __blkg_prfill_u64(struct seq_file *sf, struct blkg_policy_data *pd, u64 v);
u64 __blkg_prfill_rwstat(struct seq_file *sf, struct blkg_policy_data *pd,
const struct blkg_rwstat_sample *rwstat);
-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);
@@ -225,8 +219,6 @@ 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);
void blkg_rwstat_recursive_sum(struct blkcg_gq *blkg, struct blkcg_policy *pol,
int off, struct blkg_rwstat_sample *sum);

@@ -579,69 +571,6 @@ static inline void blkg_put(struct blkcg_gq *blkg)
if (((d_blkg) = __blkg_lookup(css_to_blkcg(pos_css), \
(p_blkg)->q, false)))

-static inline int blkg_stat_init(struct blkg_stat *stat, gfp_t gfp)
-{
- int ret;
-
- ret = percpu_counter_init(&stat->cpu_cnt, 0, gfp);
- if (ret)
- return ret;
-
- atomic64_set(&stat->aux_cnt, 0);
- return 0;
-}
-
-static inline void blkg_stat_exit(struct blkg_stat *stat)
-{
- percpu_counter_destroy(&stat->cpu_cnt);
-}
-
-/**
- * blkg_stat_add - add a value to a blkg_stat
- * @stat: target blkg_stat
- * @val: value to add
- *
- * Add @val to @stat. The caller must ensure that IRQ on the same CPU
- * don't re-enter this function for the same counter.
- */
-static inline void blkg_stat_add(struct blkg_stat *stat, uint64_t val)
-{
- percpu_counter_add_batch(&stat->cpu_cnt, val, BLKG_STAT_CPU_BATCH);
-}
-
-/**
- * blkg_stat_read - read the current value of a blkg_stat
- * @stat: blkg_stat to read
- */
-static inline uint64_t blkg_stat_read(struct blkg_stat *stat)
-{
- return percpu_counter_sum_positive(&stat->cpu_cnt);
-}
-
-/**
- * blkg_stat_reset - reset a blkg_stat
- * @stat: blkg_stat to reset
- */
-static inline void blkg_stat_reset(struct blkg_stat *stat)
-{
- percpu_counter_set(&stat->cpu_cnt, 0);
- atomic64_set(&stat->aux_cnt, 0);
-}
-
-/**
- * blkg_stat_add_aux - add a blkg_stat into another's aux count
- * @to: the destination blkg_stat
- * @from: the source
- *
- * Add @from's count including the aux one to @to's aux count.
- */
-static inline void blkg_stat_add_aux(struct blkg_stat *to,
- struct blkg_stat *from)
-{
- atomic64_add(blkg_stat_read(from) + atomic64_read(&from->aux_cnt),
- &to->aux_cnt);
-}
-
static inline int blkg_rwstat_init(struct blkg_rwstat *rwstat, gfp_t gfp)
{
int i, ret;
--
2.20.1

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