NVMe: Disk IO statistics

Add io stats accounting for bio requests so nvme block devices show
useful disk stats.

Signed-off-by: Keith Busch <keith.busch@intel.com>
Signed-off-by: Matthew Wilcox <matthew.r.wilcox@intel.com>

1 files changed, 28 insertions, 0 deletions

diff --git a/drivers/block/nvme-core.c b/drivers/block/nvme-core.c
index de3a75978c56..4e71b075d3b4 100644
--- a/drivers/block/nvme-core.c
+++ b/drivers/block/nvme-core.c
@@ -285,6 +285,7 @@ nvme_alloc_iod(unsigned nseg, unsigned nbytes, gfp_t gfp)
                 iod->npages = -1;
                 iod->length = nbytes;
                 iod->nents = 0;
+                iod->start_time = jiffies;
         }
 
         return iod;
@@ -308,6 +309,30 @@ void nvme_free_iod(struct nvme_dev *dev, struct nvme_iod *iod)
         kfree(iod);
 }
 
+static void nvme_start_io_acct(struct bio *bio)
+{
+        struct gendisk *disk = bio->bi_bdev->bd_disk;
+        const int rw = bio_data_dir(bio);
+        int cpu = part_stat_lock();
+        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();
+}
+
+static void nvme_end_io_acct(struct bio *bio, unsigned long start_time)
+{
+        struct gendisk *disk = bio->bi_bdev->bd_disk;
+        const int rw = bio_data_dir(bio);
+        unsigned long duration = jiffies - start_time;
+        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();
+}
+
 static void bio_completion(struct nvme_dev *dev, void *ctx,
                                                 struct nvme_completion *cqe)
 {
@@ -318,6 +343,8 @@ static void bio_completion(struct nvme_dev *dev, void *ctx,
         if (iod->nents)
                 dma_unmap_sg(&dev->pci_dev->dev, iod->sg, iod->nents,
                         bio_data_dir(bio) ? DMA_TO_DEVICE : DMA_FROM_DEVICE);
+
+        nvme_end_io_acct(bio, iod->start_time);
         nvme_free_iod(dev, iod);
         if (status)
                 bio_endio(bio, -EIO);
@@ -695,6 +722,7 @@ static int nvme_submit_bio_queue(struct nvme_queue *nvmeq, struct nvme_ns *ns,
         cmnd->rw.control = cpu_to_le16(control);
         cmnd->rw.dsmgmt = cpu_to_le32(dsmgmt);
 
+        nvme_start_io_acct(bio);
         if (++nvmeq->sq_tail == nvmeq->q_depth)
                 nvmeq->sq_tail = 0;
         writel(nvmeq->sq_tail, nvmeq->q_db);