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Mon, 01 Apr 2019 18:59:44 +0300 (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (Client certificate not present) Subject: [PATCH 1/3] block/diskstats: accumulate all per-cpu counters in one pass From: Konstantin Khlebnikov To: linux-block@vger.kernel.org, Jens Axboe , linux-kernel@vger.kernel.org Cc: Mikulas Patocka , Mike Snitzer Date: Mon, 01 Apr 2019 18:59:43 +0300 Message-ID: <155413438394.3201.15211440151043943989.stgit@buzz> User-Agent: StGit/0.17.1-dirty MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This is faster and makes code much smaller: ./scripts/bloat-o-meter vmlinux.before vmlinux.after add/remove: 1/0 grow/shrink: 0/2 up/down: 176/-1348 (-1172) Function old new delta part_stat_read_all - 176 +176 diskstats_show 1190 569 -621 part_stat_show 1064 337 -727 Total: Before=13762189, After=13761017, chg -0.01% Signed-off-by: Konstantin Khlebnikov --- block/genhd.c | 62 +++++++++++++++++++++++++++++++++++---------- block/partition-generic.c | 31 ++++++++++++----------- include/linux/genhd.h | 5 +--- 3 files changed, 67 insertions(+), 31 deletions(-) diff --git a/block/genhd.c b/block/genhd.c index 703267865f14..2f986af81ba1 100644 --- a/block/genhd.c +++ b/block/genhd.c @@ -45,6 +45,34 @@ static void disk_add_events(struct gendisk *disk); static void disk_del_events(struct gendisk *disk); static void disk_release_events(struct gendisk *disk); +#ifdef CONFIG_SMP +void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat) +{ + int cpu; + + memset(stat, 0, sizeof(struct disk_stats)); + for_each_possible_cpu(cpu) { + struct disk_stats *ptr = per_cpu_ptr(part->dkstats, cpu); + int group; + + for (group = 0; group < NR_STAT_GROUPS; group++) { + stat->nsecs[group] += ptr->nsecs[group]; + stat->sectors[group] += ptr->sectors[group]; + stat->ios[group] += ptr->ios[group]; + stat->merges[group] += ptr->merges[group]; + } + + stat->io_ticks += ptr->io_ticks; + stat->time_in_queue += ptr->time_in_queue; + } +} +#else /* CONFIG_SMP */ +void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat) +{ + memcpy(stat, &part->dkstats, sizeof(struct disk_stats)); +} +#endif /* CONFIG_SMP */ + void part_inc_in_flight(struct request_queue *q, struct hd_struct *part, int rw) { if (queue_is_mq(q)) @@ -1341,6 +1369,7 @@ static int diskstats_show(struct seq_file *seqf, void *v) struct hd_struct *hd; char buf[BDEVNAME_SIZE]; unsigned int inflight; + struct disk_stats stat; /* if (&disk_to_dev(gp)->kobj.entry == block_class.devices.next) @@ -1352,7 +1381,9 @@ static int diskstats_show(struct seq_file *seqf, void *v) disk_part_iter_init(&piter, gp, DISK_PITER_INCL_EMPTY_PART0); while ((hd = disk_part_iter_next(&piter))) { + part_stat_read_all(hd, &stat); inflight = part_in_flight(gp->queue, hd); + seq_printf(seqf, "%4d %7d %s " "%lu %lu %lu %u " "%lu %lu %lu %u " @@ -1360,21 +1391,24 @@ static int diskstats_show(struct seq_file *seqf, void *v) "%lu %lu %lu %u\n", MAJOR(part_devt(hd)), MINOR(part_devt(hd)), disk_name(gp, hd->partno, buf), - part_stat_read(hd, ios[STAT_READ]), - part_stat_read(hd, merges[STAT_READ]), - part_stat_read(hd, sectors[STAT_READ]), - (unsigned int)part_stat_read_msecs(hd, STAT_READ), - part_stat_read(hd, ios[STAT_WRITE]), - part_stat_read(hd, merges[STAT_WRITE]), - part_stat_read(hd, sectors[STAT_WRITE]), - (unsigned int)part_stat_read_msecs(hd, STAT_WRITE), + stat.ios[STAT_READ], + stat.merges[STAT_READ], + stat.sectors[STAT_READ], + (unsigned int)div_u64(stat.nsecs[STAT_READ], + NSEC_PER_MSEC), + stat.ios[STAT_WRITE], + stat.merges[STAT_WRITE], + stat.sectors[STAT_WRITE], + (unsigned int)div_u64(stat.nsecs[STAT_WRITE], + NSEC_PER_MSEC), inflight, - jiffies_to_msecs(part_stat_read(hd, io_ticks)), - jiffies_to_msecs(part_stat_read(hd, time_in_queue)), - part_stat_read(hd, ios[STAT_DISCARD]), - part_stat_read(hd, merges[STAT_DISCARD]), - part_stat_read(hd, sectors[STAT_DISCARD]), - (unsigned int)part_stat_read_msecs(hd, STAT_DISCARD) + jiffies_to_msecs(stat.io_ticks), + jiffies_to_msecs(stat.time_in_queue), + stat.ios[STAT_DISCARD], + stat.merges[STAT_DISCARD], + stat.sectors[STAT_DISCARD], + (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], + NSEC_PER_MSEC) ); } disk_part_iter_exit(&piter); diff --git a/block/partition-generic.c b/block/partition-generic.c index 8e596a8dff32..621e0d9f3c92 100644 --- a/block/partition-generic.c +++ b/block/partition-generic.c @@ -120,30 +120,33 @@ ssize_t part_stat_show(struct device *dev, { struct hd_struct *p = dev_to_part(dev); struct request_queue *q = part_to_disk(p)->queue; + struct disk_stats stat; unsigned int inflight; + part_stat_read_all(p, &stat); inflight = part_in_flight(q, p); + return sprintf(buf, "%8lu %8lu %8llu %8u " "%8lu %8lu %8llu %8u " "%8u %8u %8u " "%8lu %8lu %8llu %8u" "\n", - part_stat_read(p, ios[STAT_READ]), - part_stat_read(p, merges[STAT_READ]), - (unsigned long long)part_stat_read(p, sectors[STAT_READ]), - (unsigned int)part_stat_read_msecs(p, STAT_READ), - part_stat_read(p, ios[STAT_WRITE]), - part_stat_read(p, merges[STAT_WRITE]), - (unsigned long long)part_stat_read(p, sectors[STAT_WRITE]), - (unsigned int)part_stat_read_msecs(p, STAT_WRITE), + stat.ios[STAT_READ], + stat.merges[STAT_READ], + (unsigned long long)stat.sectors[STAT_READ], + (unsigned int)div_u64(stat.nsecs[STAT_READ], NSEC_PER_MSEC), + stat.ios[STAT_WRITE], + stat.merges[STAT_WRITE], + (unsigned long long)stat.sectors[STAT_WRITE], + (unsigned int)div_u64(stat.nsecs[STAT_WRITE], NSEC_PER_MSEC), inflight, - jiffies_to_msecs(part_stat_read(p, io_ticks)), - jiffies_to_msecs(part_stat_read(p, time_in_queue)), - part_stat_read(p, ios[STAT_DISCARD]), - part_stat_read(p, merges[STAT_DISCARD]), - (unsigned long long)part_stat_read(p, sectors[STAT_DISCARD]), - (unsigned int)part_stat_read_msecs(p, STAT_DISCARD)); + jiffies_to_msecs(stat.io_ticks), + jiffies_to_msecs(stat.time_in_queue), + stat.ios[STAT_DISCARD], + stat.merges[STAT_DISCARD], + (unsigned long long)stat.sectors[STAT_DISCARD], + (unsigned int)div_u64(stat.nsecs[STAT_DISCARD], NSEC_PER_MSEC)); } ssize_t part_inflight_show(struct device *dev, struct device_attribute *attr, diff --git a/include/linux/genhd.h b/include/linux/genhd.h index 06c0fd594097..7f981be190b4 100644 --- a/include/linux/genhd.h +++ b/include/linux/genhd.h @@ -357,9 +357,6 @@ static inline void free_part_stats(struct hd_struct *part) #endif /* CONFIG_SMP */ -#define part_stat_read_msecs(part, which) \ - div_u64(part_stat_read(part, nsecs[which]), NSEC_PER_MSEC) - #define part_stat_read_accum(part, field) \ (part_stat_read(part, field[STAT_READ]) + \ part_stat_read(part, field[STAT_WRITE]) + \ @@ -391,6 +388,8 @@ static inline void free_part_stats(struct hd_struct *part) #define part_stat_local_read_cpu(gendiskp, field, cpu) \ local_read(&(part_stat_get_cpu(gendiskp, field, cpu))) +void part_stat_read_all(struct hd_struct *part, struct disk_stats *stat); + unsigned int part_in_flight(struct request_queue *q, struct hd_struct *part); void part_in_flight_rw(struct request_queue *q, struct hd_struct *part, unsigned int inflight[2]);