From: Pavel Begunkov <[email protected]> Split struct blk_rq_stat into 2 structs, so each would explicitely represent one of the mentioned states. That duplicates code, but 1. prevents misuses (compile-time check by type-system) 2. reduces memory needed (inc. per-cpu) 3. makes it easier to extend stats
Signed-off-by: Pavel Begunkov <[email protected]> --- block/blk-iolatency.c | 41 +++++++++++++++++++++++++++++---------- block/blk-stat.c | 30 +++++++++++++++++----------- block/blk-stat.h | 8 +++++--- include/linux/blk_types.h | 6 ++++++ 4 files changed, 61 insertions(+), 24 deletions(-) diff --git a/block/blk-iolatency.c b/block/blk-iolatency.c index fc8ce1a0ae21..fbf986a0b8c2 100644 --- a/block/blk-iolatency.c +++ b/block/blk-iolatency.c @@ -130,9 +130,16 @@ struct latency_stat { }; }; +struct latency_stat_staging { + union { + struct percentile_stats ps; + struct blk_rq_stat_staging rqs; + }; +}; + struct iolatency_grp { struct blkg_policy_data pd; - struct latency_stat __percpu *stats; + struct latency_stat_staging __percpu *stats; struct latency_stat cur_stat; struct blk_iolatency *blkiolat; struct rq_depth rq_depth; @@ -199,6 +206,16 @@ static inline void latency_stat_init(struct iolatency_grp *iolat, blk_rq_stat_init(&stat->rqs); } +static inline void latency_stat_init_staging(struct iolatency_grp *iolat, + struct latency_stat_staging *stat) +{ + if (iolat->ssd) { + stat->ps.total = 0; + stat->ps.missed = 0; + } else + blk_rq_stat_init_staging(&stat->rqs); +} + static inline void latency_stat_merge(struct iolatency_grp *iolat, struct latency_stat *sum, struct latency_stat *stat) @@ -212,7 +229,7 @@ static inline void latency_stat_merge(struct iolatency_grp *iolat, static inline void latency_stat_collect(struct iolatency_grp *iolat, struct latency_stat *sum, - struct latency_stat *stat) + struct latency_stat_staging *stat) { if (iolat->ssd) { sum->ps.total += stat->ps.total; @@ -224,7 +241,8 @@ static inline void latency_stat_collect(struct iolatency_grp *iolat, static inline void latency_stat_record_time(struct iolatency_grp *iolat, u64 req_time) { - struct latency_stat *stat = get_cpu_ptr(iolat->stats); + struct latency_stat_staging *stat = get_cpu_ptr(iolat->stats); + if (iolat->ssd) { if (req_time >= iolat->min_lat_nsec) stat->ps.missed++; @@ -540,10 +558,11 @@ static void iolatency_check_latencies(struct iolatency_grp *iolat, u64 now) latency_stat_init(iolat, &stat); preempt_disable(); for_each_online_cpu(cpu) { - struct latency_stat *s; + struct latency_stat_staging *s; + s = per_cpu_ptr(iolat->stats, cpu); latency_stat_collect(iolat, &stat, s); - latency_stat_init(iolat, s); + latency_stat_init_staging(iolat, s); } preempt_enable(); @@ -922,7 +941,8 @@ static size_t iolatency_ssd_stat(struct iolatency_grp *iolat, char *buf, latency_stat_init(iolat, &stat); preempt_disable(); for_each_online_cpu(cpu) { - struct latency_stat *s; + struct latency_stat_staging *s; + s = per_cpu_ptr(iolat->stats, cpu); latency_stat_collect(iolat, &stat, s); } @@ -966,8 +986,8 @@ static struct blkg_policy_data *iolatency_pd_alloc(gfp_t gfp, int node) iolat = kzalloc_node(sizeof(*iolat), gfp, node); if (!iolat) return NULL; - iolat->stats = __alloc_percpu_gfp(sizeof(struct latency_stat), - __alignof__(struct latency_stat), gfp); + iolat->stats = __alloc_percpu_gfp(sizeof(struct latency_stat_staging), + __alignof__(struct latency_stat_staging), gfp); if (!iolat->stats) { kfree(iolat); return NULL; @@ -990,9 +1010,10 @@ static void iolatency_pd_init(struct blkg_policy_data *pd) iolat->ssd = false; for_each_possible_cpu(cpu) { - struct latency_stat *stat; + struct latency_stat_staging *stat; + stat = per_cpu_ptr(iolat->stats, cpu); - latency_stat_init(iolat, stat); + latency_stat_init_staging(iolat, stat); } latency_stat_init(iolat, &iolat->cur_stat); diff --git a/block/blk-stat.c b/block/blk-stat.c index 78389182b5d0..d892ad2cb938 100644 --- a/block/blk-stat.c +++ b/block/blk-stat.c @@ -18,15 +18,22 @@ struct blk_queue_stats { bool enable_accounting; }; +void blk_rq_stat_init_staging(struct blk_rq_stat_staging *stat) +{ + stat->min = -1ULL; + stat->max = 0; + stat->batch = 0; + stat->nr_samples = 0; +} + void blk_rq_stat_init(struct blk_rq_stat *stat) { stat->min = -1ULL; stat->max = stat->nr_samples = stat->mean = 0; - stat->batch = 0; } -/* src is a per-cpu stat, mean isn't initialized */ -void blk_rq_stat_collect(struct blk_rq_stat *dst, struct blk_rq_stat *src) +void blk_rq_stat_collect(struct blk_rq_stat *dst, + struct blk_rq_stat_staging *src) { if (!src->nr_samples) return; @@ -55,7 +62,7 @@ void blk_rq_stat_merge(struct blk_rq_stat *dst, struct blk_rq_stat *src) dst->nr_samples += src->nr_samples; } -void blk_rq_stat_add(struct blk_rq_stat *stat, u64 value) +void blk_rq_stat_add(struct blk_rq_stat_staging *stat, u64 value) { stat->min = min(stat->min, value); stat->max = max(stat->max, value); @@ -67,7 +74,7 @@ void blk_stat_add(struct request *rq, u64 now) { struct request_queue *q = rq->q; struct blk_stat_callback *cb; - struct blk_rq_stat *stat; + struct blk_rq_stat_staging *stat; int bucket; u64 value; @@ -101,13 +108,13 @@ static void blk_stat_timer_fn(struct timer_list *t) blk_rq_stat_init(&cb->stat[bucket]); for_each_online_cpu(cpu) { - struct blk_rq_stat *cpu_stat; + struct blk_rq_stat_staging *cpu_stat; cpu_stat = per_cpu_ptr(cb->cpu_stat, cpu); for (bucket = 0; bucket < cb->buckets; bucket++) { blk_rq_stat_collect(&cb->stat[bucket], &cpu_stat[bucket]); - blk_rq_stat_init(&cpu_stat[bucket]); + blk_rq_stat_init_staging(&cpu_stat[bucket]); } } @@ -131,8 +138,9 @@ blk_stat_alloc_callback(void (*timer_fn)(struct blk_stat_callback *), kfree(cb); return NULL; } - cb->cpu_stat = __alloc_percpu(buckets * sizeof(struct blk_rq_stat), - __alignof__(struct blk_rq_stat)); + cb->cpu_stat = __alloc_percpu( + buckets * sizeof(struct blk_rq_stat_staging), + __alignof__(struct blk_rq_stat_staging)); if (!cb->cpu_stat) { kfree(cb->stat); kfree(cb); @@ -155,11 +163,11 @@ void blk_stat_add_callback(struct request_queue *q, int cpu; for_each_possible_cpu(cpu) { - struct blk_rq_stat *cpu_stat; + struct blk_rq_stat_staging *cpu_stat; cpu_stat = per_cpu_ptr(cb->cpu_stat, cpu); for (bucket = 0; bucket < cb->buckets; bucket++) - blk_rq_stat_init(&cpu_stat[bucket]); + blk_rq_stat_init_staging(&cpu_stat[bucket]); } spin_lock(&q->stats->lock); diff --git a/block/blk-stat.h b/block/blk-stat.h index 5597ecc34ef5..e5c753fbd6e6 100644 --- a/block/blk-stat.h +++ b/block/blk-stat.h @@ -30,7 +30,7 @@ struct blk_stat_callback { /** * @cpu_stat: Per-cpu statistics buckets. */ - struct blk_rq_stat __percpu *cpu_stat; + struct blk_rq_stat_staging __percpu *cpu_stat; /** * @bucket_fn: Given a request, returns which statistics bucket it @@ -164,9 +164,11 @@ static inline void blk_stat_activate_msecs(struct blk_stat_callback *cb, mod_timer(&cb->timer, jiffies + msecs_to_jiffies(msecs)); } -void blk_rq_stat_add(struct blk_rq_stat *, u64); -void blk_rq_stat_collect(struct blk_rq_stat *dst, struct blk_rq_stat *src); +void blk_rq_stat_add(struct blk_rq_stat_staging *stat, u64); +void blk_rq_stat_collect(struct blk_rq_stat *dst, + struct blk_rq_stat_staging *src); void blk_rq_stat_merge(struct blk_rq_stat *dst, struct blk_rq_stat *src); void blk_rq_stat_init(struct blk_rq_stat *); +void blk_rq_stat_init_staging(struct blk_rq_stat_staging *stat); #endif diff --git a/include/linux/blk_types.h b/include/linux/blk_types.h index be418275763c..2db5a5fd318f 100644 --- a/include/linux/blk_types.h +++ b/include/linux/blk_types.h @@ -449,7 +449,13 @@ struct blk_rq_stat { u64 min; u64 max; u32 nr_samples; +}; + +struct blk_rq_stat_staging { + u64 min; + u64 max; u64 batch; + u32 nr_samples; }; #endif /* __LINUX_BLK_TYPES_H */ -- 2.22.0
