Add /sys/kernel/debug/block/$DEV/rqos/inflight/lat interface to display the dynamic latency of online cgroups. Signed-off-by: Baokun Li <libaokun1@huawei.com> --- block/blk-ioinf.c | 105 +++++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 103 insertions(+), 2 deletions(-) diff --git a/block/blk-ioinf.c b/block/blk-ioinf.c index 623cbfca2823..6627a003312c 100644 --- a/block/blk-ioinf.c +++ b/block/blk-ioinf.c @@ -35,6 +35,16 @@ struct ioinf_params { u32 inflight; }; +struct ioinf_io_stat { + u64 nr; + u64 lat; +}; + +struct ioinf_lat_stat { + struct ioinf_io_stat read; + struct ioinf_io_stat write; +}; + struct ioinf_rq_wait { struct rq_wait rqw; u32 hinflight; @@ -62,6 +72,10 @@ struct ioinf { struct ioinf_rq_wait offline; /* for online cgroups */ struct ioinf_rq_wait online; + + struct ioinf_lat_stat last_stat; + struct ioinf_lat_stat delta_stat; + struct ioinf_lat_stat __percpu *stat; }; /* per disk-cgroup pair structure */ @@ -298,6 +312,27 @@ static void ioinf_rqos_track(struct rq_qos *rqos, struct request *rq, rq->blkg = blkg; } +static void ioinf_record_lat(struct ioinf *inf, struct request *rq) +{ + u64 lat; + + lat = rq->io_end_time_ns ? rq->io_end_time_ns : blk_time_get_ns(); + lat -= rq->alloc_time_ns; + + switch(req_op(rq)) { + case REQ_OP_READ: + this_cpu_inc(inf->stat->read.nr); + this_cpu_add(inf->stat->read.lat, lat); + break; + case REQ_OP_WRITE: + this_cpu_inc(inf->stat->write.nr); + this_cpu_add(inf->stat->write.lat, lat); + break; + default: + break; + } +} + static void ioinf_rqos_done(struct rq_qos *rqos, struct request *rq) { struct blkcg_gq *blkg = rq->blkg; @@ -309,10 +344,12 @@ static void ioinf_rqos_done(struct rq_qos *rqos, struct request *rq) infg = blkg_to_infg(blkg); inf = infg->inf; - if (infg_offline(infg)) + if (infg_offline(infg)) { ioinf_done(&inf->offline); - else + } else { ioinf_done(&inf->online); + ioinf_record_lat(inf, rq); + } rq->blkg = NULL; } @@ -324,6 +361,7 @@ static void ioinf_rqos_exit(struct rq_qos *rqos) blkcg_deactivate_policy(rqos->disk, &blkcg_policy_ioinf); timer_shutdown_sync(&inf->inf_timer); + free_percpu(inf->stat); kfree(inf); } @@ -348,8 +386,21 @@ static int ioinf_stat_show(void *data, struct seq_file *m) return 0; } +static int ioinf_lat_show(void *data, struct seq_file *m) +{ + struct rq_qos *rqos = data; + struct ioinf *inf = rqos_to_inf(rqos); + struct ioinf_lat_stat *stat = &inf->delta_stat; + + seq_printf(m, "online average latency: (%llu-%llu) (%llu-%llu)\n", + stat->read.nr, stat->read.lat, stat->write.nr, stat->write.lat); + + return 0; +} + static const struct blk_mq_debugfs_attr ioinf_debugfs_attrs[] = { {"stat", 0400, ioinf_stat_show}, + {"lat", 0400, ioinf_lat_show}, {}, }; @@ -378,6 +429,46 @@ u32 ioinf_calc_budget(struct ioinf_rq_wait *ioinf_rqw) return new_budget; } +static void ioinf_sample_cpu_lat(struct ioinf_lat_stat *cur, int cpu, + struct ioinf_lat_stat __percpu *stat) +{ + struct ioinf_lat_stat *pstat = per_cpu_ptr(stat, cpu); + + cur->read.nr += pstat->read.nr; + cur->read.lat += pstat->read.lat; + cur->write.nr += pstat->write.nr; + cur->write.lat += pstat->write.lat; +} + +static struct ioinf_lat_stat ioinf_calc_stat(struct ioinf_lat_stat *cur, + struct ioinf_lat_stat *last) +{ + struct ioinf_lat_stat delta = {0}; + + delta.read.nr = cur->read.nr - last->read.nr; + delta.read.lat = cur->read.lat - last->read.lat; + if (delta.read.nr > 0) + delta.read.lat = delta.read.lat / delta.read.nr; + + delta.write.nr = cur->write.nr - last->write.nr; + delta.write.lat = cur->write.lat - last->write.lat; + if (delta.write.nr > 0) + delta.write.lat = delta.write.lat / delta.write.nr; + + return delta; +} + +static void ioinf_sample_lat(struct ioinf *inf) +{ + struct ioinf_lat_stat cur = {0}; + int cpu; + + for_each_possible_cpu(cpu) + ioinf_sample_cpu_lat(&cur, cpu, inf->stat); + inf->delta_stat = ioinf_calc_stat(&cur, &inf->last_stat); + inf->last_stat = cur; +} + static void ioinf_update_inflight(struct ioinf *inf, u32 new_online, u32 new_offline) { @@ -408,6 +499,7 @@ static void ioinf_timer_fn(struct timer_list *timer) unsigned long flags; u32 online_budget, offline_budget; + ioinf_sample_lat(inf); spin_lock_irqsave(&inf->lock, flags); online_budget = ioinf_calc_budget(online); @@ -432,6 +524,12 @@ static int blk_ioinf_init(struct gendisk *disk) if (!inf) return -ENOMEM; + inf->stat = alloc_percpu(struct ioinf_lat_stat); + if (!inf->stat) { + kfree(inf); + return -ENOMEM; + } + spin_lock_init(&inf->lock); inf->params.inflight = ioinf_default_inflight(disk); inf->inflight = inf->params.inflight; @@ -455,6 +553,7 @@ static int blk_ioinf_init(struct gendisk *disk) rq_qos_del(&inf->rqos); err_free_inf: timer_shutdown_sync(&inf->inf_timer); + free_percpu(inf->stat); kfree(inf); return ret; } @@ -611,7 +710,9 @@ static ssize_t ioinf_qos_write(struct kernfs_open_file *of, char *input, inf = q_to_inf(disk->queue); if (!params.inflight) params.inflight = inf->params.inflight; + blk_queue_flag_set(QUEUE_FLAG_RQ_ALLOC_TIME, disk->queue); } else if (inf && !params.enabled) { + blk_queue_flag_clear(QUEUE_FLAG_RQ_ALLOC_TIME, disk->queue); timer_shutdown_sync(&inf->inf_timer); blkcg_deactivate_policy(inf->rqos.disk, &blkcg_policy_ioinf); rq_qos_del(&inf->rqos); -- 2.46.1