This is disabled by default as the overhead is prohibitive, but if the user takes the action to turn it on we'll oblige.
Reviewed-by: Vishal Verma <[email protected]> Signed-off-by: Dan Williams <[email protected]> --- drivers/nvdimm/Kconfig | 14 ++++++++++++++ drivers/nvdimm/blk.c | 7 ++++++- drivers/nvdimm/btt.c | 7 ++++++- drivers/nvdimm/core.c | 31 +++++++++++++++++++++++++++++++ drivers/nvdimm/nd.h | 13 +++++++++++++ drivers/nvdimm/pmem.c | 5 +++++ 6 files changed, 75 insertions(+), 2 deletions(-) diff --git a/drivers/nvdimm/Kconfig b/drivers/nvdimm/Kconfig index 912cb36b8435..9d72085a67c9 100644 --- a/drivers/nvdimm/Kconfig +++ b/drivers/nvdimm/Kconfig @@ -73,4 +73,18 @@ config ND_MAX_REGIONS Leave the default of 64 if you are unsure. +config ND_IOSTAT + bool "Enable iostat by default" + default n + ---help--- + Persistent memory i/o has very low latency to the point + where the overhead to measure statistics can dramatically + impact the relative performance of the driver. Say y here + to trade off performance for statistics gathering that is + enabled by default. These statistics can always be + enabled/disabled at run time via the 'iostat' attribute of + the block device's queue in sysfs. + + If unsure, say N + endif diff --git a/drivers/nvdimm/blk.c b/drivers/nvdimm/blk.c index 9d609ef95266..8a65e5a500d8 100644 --- a/drivers/nvdimm/blk.c +++ b/drivers/nvdimm/blk.c @@ -168,8 +168,10 @@ static void nd_blk_make_request(struct request_queue *q, struct bio *bio) struct bio_integrity_payload *bip; struct nd_blk_device *blk_dev; struct bvec_iter iter; + unsigned long start; struct bio_vec bvec; int err = 0, rw; + bool do_acct; if (unlikely(bio_end_sector(bio) > get_capacity(disk))) { err = -EIO; @@ -191,6 +193,7 @@ static void nd_blk_make_request(struct request_queue *q, struct bio *bio) blk_dev = disk->private_data; rw = bio_data_dir(bio); + do_acct = nd_iostat_start(bio, &start); bio_for_each_segment(bvec, bio, iter) { unsigned int len = bvec.bv_len; @@ -202,9 +205,11 @@ static void nd_blk_make_request(struct request_queue *q, struct bio *bio) "io error in %s sector %lld, len %d,\n", (rw == READ) ? "READ" : "WRITE", (unsigned long long) iter.bi_sector, len); - goto out; + break; } } + if (do_acct) + nd_iostat_end(bio, start); out: bio_endio(bio, err); diff --git a/drivers/nvdimm/btt.c b/drivers/nvdimm/btt.c index 83b798dd2e68..67484633c322 100644 --- a/drivers/nvdimm/btt.c +++ b/drivers/nvdimm/btt.c @@ -1178,8 +1178,10 @@ static void btt_make_request(struct request_queue *q, struct bio *bio) struct block_device *bdev = bio->bi_bdev; struct btt *btt = q->queuedata; struct bvec_iter iter; + unsigned long start; struct bio_vec bvec; int err = 0, rw; + bool do_acct; if (bio_end_sector(bio) > get_capacity(bdev->bd_disk)) { err = -EIO; @@ -1199,6 +1201,7 @@ static void btt_make_request(struct request_queue *q, struct bio *bio) goto out; } + do_acct = nd_iostat_start(bio, &start); bio_for_each_segment(bvec, bio, iter) { unsigned int len = bvec.bv_len; @@ -1215,9 +1218,11 @@ static void btt_make_request(struct request_queue *q, struct bio *bio) "io error in %s sector %lld, len %d,\n", (rw == READ) ? "READ" : "WRITE", (unsigned long long) iter.bi_sector, len); - goto out; + break; } } + if (do_acct) + nd_iostat_end(bio, start); out: bio_endio(bio, err); diff --git a/drivers/nvdimm/core.c b/drivers/nvdimm/core.c index d27b13357873..99cf95af5f24 100644 --- a/drivers/nvdimm/core.c +++ b/drivers/nvdimm/core.c @@ -218,9 +218,40 @@ void nd_blk_queue_init(struct request_queue *q) { blk_queue_max_hw_sectors(q, UINT_MAX); blk_queue_bounce_limit(q, BLK_BOUNCE_ANY); + if (IS_ENABLED(CONFIG_ND_IOSTAT)) + queue_flag_set_unlocked(QUEUE_FLAG_IO_STAT, q); } EXPORT_SYMBOL(nd_blk_queue_init); +void __nd_iostat_start(struct bio *bio, unsigned long *start) +{ + struct gendisk *disk = bio->bi_bdev->bd_disk; + const int rw = bio_data_dir(bio); + int cpu = part_stat_lock(); + + *start = jiffies; + part_round_stats(cpu, &disk->part0); + part_stat_inc(cpu, &disk->part0, ios[rw]); + part_stat_add(cpu, &disk->part0, sectors[rw], bio_sectors(bio)); + part_inc_in_flight(&disk->part0, rw); + part_stat_unlock(); +} +EXPORT_SYMBOL(__nd_iostat_start); + +void nd_iostat_end(struct bio *bio, unsigned long start) +{ + struct gendisk *disk = bio->bi_bdev->bd_disk; + unsigned long duration = jiffies - start; + const int rw = bio_data_dir(bio); + int cpu = part_stat_lock(); + + part_stat_add(cpu, &disk->part0, ticks[rw], duration); + part_round_stats(cpu, &disk->part0); + part_dec_in_flight(&disk->part0, rw); + part_stat_unlock(); +} +EXPORT_SYMBOL(nd_iostat_end); + static ssize_t commands_show(struct device *dev, struct device_attribute *attr, char *buf) { diff --git a/drivers/nvdimm/nd.h b/drivers/nvdimm/nd.h index 2f20d5dca028..3c4c8b6c64ec 100644 --- a/drivers/nvdimm/nd.h +++ b/drivers/nvdimm/nd.h @@ -13,6 +13,7 @@ #ifndef __ND_H__ #define __ND_H__ #include <linux/libnvdimm.h> +#include <linux/blkdev.h> #include <linux/device.h> #include <linux/genhd.h> #include <linux/mutex.h> @@ -172,5 +173,17 @@ struct resource *nvdimm_allocate_dpa(struct nvdimm_drvdata *ndd, resource_size_t n); int nd_blk_region_init(struct nd_region *nd_region); void nd_blk_queue_init(struct request_queue *q); +void __nd_iostat_start(struct bio *bio, unsigned long *start); +static inline bool nd_iostat_start(struct bio *bio, unsigned long *start) +{ + struct gendisk *disk = bio->bi_bdev->bd_disk; + + if (!blk_queue_io_stat(disk->queue)) + return false; + + __nd_iostat_start(bio, start); + return true; +} +void nd_iostat_end(struct bio *bio, unsigned long start); resource_size_t nd_namespace_blk_validate(struct nd_namespace_blk *nsblk); #endif /* __ND_H__ */ diff --git a/drivers/nvdimm/pmem.c b/drivers/nvdimm/pmem.c index 0337b00f5409..3fd854a78f09 100644 --- a/drivers/nvdimm/pmem.c +++ b/drivers/nvdimm/pmem.c @@ -59,6 +59,8 @@ static void pmem_do_bvec(struct pmem_device *pmem, struct page *page, static void pmem_make_request(struct request_queue *q, struct bio *bio) { int err = 0; + bool do_acct; + unsigned long start; struct bio_vec bvec; struct bvec_iter iter; struct block_device *bdev = bio->bi_bdev; @@ -69,9 +71,12 @@ static void pmem_make_request(struct request_queue *q, struct bio *bio) goto out; } + do_acct = nd_iostat_start(bio, &start); bio_for_each_segment(bvec, bio, iter) pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset, bio_data_dir(bio), iter.bi_sector); + if (do_acct) + nd_iostat_end(bio, start); out: bio_endio(bio, err); -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [email protected] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
