From: Yu Kuai <yukuai3@huawei.com>
Date: Thu, 23 Feb 2023 17:12:26 +0800
Subject: [PATCH] block: count 'ios' and 'sectors' when io is done for
bio-based device
References: bsc#1012628
Patch-mainline: 6.2.8
Git-commit: 5f27571382ca42daa3e3d40d1b252bf18c2b61d2
[ Upstream commit 5f27571382ca42daa3e3d40d1b252bf18c2b61d2 ]
While using iostat for raid, I observed very strange 'await'
occasionally, and turns out it's due to that 'ios' and 'sectors' is
counted in bdev_start_io_acct(), while 'nsecs' is counted in
bdev_end_io_acct(). I'm not sure why they are ccounted like that
but I think this behaviour is obviously wrong because user will get
wrong disk stats.
Fix the problem by counting 'ios' and 'sectors' when io is done, like
what rq-based device does.
Fixes: 394ffa503bc4 ("blk: introduce generic io stat accounting help function")
Signed-off-by: Yu Kuai <yukuai3@huawei.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Link: https://lore.kernel.org/r/20230223091226.1135678-1-yukuai1@huaweicloud.com
Signed-off-by: Jens Axboe <axboe@kernel.dk>
Signed-off-by: Sasha Levin <sashal@kernel.org>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>
---
block/blk-core.c | 16 ++++++----------
drivers/block/zram/zram_drv.c | 4 ++--
drivers/md/dm.c | 6 +++---
drivers/nvme/host/multipath.c | 8 ++++----
include/linux/blkdev.h | 5 ++---
5 files changed, 17 insertions(+), 22 deletions(-)
diff --git a/block/blk-core.c b/block/blk-core.c
index 5a004921..59729315 100644
--- a/block/blk-core.c
+++ b/block/blk-core.c
@@ -946,16 +946,11 @@ void update_io_ticks(struct block_device *part, unsigned long now, bool end)
}
}
-unsigned long bdev_start_io_acct(struct block_device *bdev,
- unsigned int sectors, enum req_op op,
+unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op,
unsigned long start_time)
{
- const int sgrp = op_stat_group(op);
-
part_stat_lock();
update_io_ticks(bdev, start_time, false);
- part_stat_inc(bdev, ios[sgrp]);
- part_stat_add(bdev, sectors[sgrp], sectors);
part_stat_local_inc(bdev, in_flight[op_is_write(op)]);
part_stat_unlock();
@@ -971,13 +966,12 @@ EXPORT_SYMBOL(bdev_start_io_acct);
*/
unsigned long bio_start_io_acct(struct bio *bio)
{
- return bdev_start_io_acct(bio->bi_bdev, bio_sectors(bio),
- bio_op(bio), jiffies);
+ return bdev_start_io_acct(bio->bi_bdev, bio_op(bio), jiffies);
}
EXPORT_SYMBOL_GPL(bio_start_io_acct);
void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
- unsigned long start_time)
+ unsigned int sectors, unsigned long start_time)
{
const int sgrp = op_stat_group(op);
unsigned long now = READ_ONCE(jiffies);
@@ -985,6 +979,8 @@ void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
part_stat_lock();
update_io_ticks(bdev, now, true);
+ part_stat_inc(bdev, ios[sgrp]);
+ part_stat_add(bdev, sectors[sgrp], sectors);
part_stat_add(bdev, nsecs[sgrp], jiffies_to_nsecs(duration));
part_stat_local_dec(bdev, in_flight[op_is_write(op)]);
part_stat_unlock();
@@ -994,7 +990,7 @@ EXPORT_SYMBOL(bdev_end_io_acct);
void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
struct block_device *orig_bdev)
{
- bdev_end_io_acct(orig_bdev, bio_op(bio), start_time);
+ bdev_end_io_acct(orig_bdev, bio_op(bio), bio_sectors(bio), start_time);
}
EXPORT_SYMBOL_GPL(bio_end_io_acct_remapped);
diff --git a/drivers/block/zram/zram_drv.c b/drivers/block/zram/zram_drv.c
index e290d6d9..03ef03e1 100644
--- a/drivers/block/zram/zram_drv.c
+++ b/drivers/block/zram/zram_drv.c
@@ -2108,9 +2108,9 @@ static int zram_rw_page(struct block_device *bdev, sector_t sector,
bv.bv_offset = 0;
start_time = bdev_start_io_acct(bdev->bd_disk->part0,
- SECTORS_PER_PAGE, op, jiffies);
+ op, jiffies);
ret = zram_bvec_rw(zram, &bv, index, offset, op, NULL);
- bdev_end_io_acct(bdev->bd_disk->part0, op, start_time);
+ bdev_end_io_acct(bdev->bd_disk->part0, op, SECTORS_PER_PAGE, start_time);
out:
/*
* If I/O fails, just return error(ie, non-zero) without
diff --git a/drivers/md/dm.c b/drivers/md/dm.c
index 60566293..fdcf4255 100644
--- a/drivers/md/dm.c
+++ b/drivers/md/dm.c
@@ -510,10 +510,10 @@ static void dm_io_acct(struct dm_io *io, bool end)
sectors = io->sectors;
if (!end)
- bdev_start_io_acct(bio->bi_bdev, sectors, bio_op(bio),
- start_time);
+ bdev_start_io_acct(bio->bi_bdev, bio_op(bio), start_time);
else
- bdev_end_io_acct(bio->bi_bdev, bio_op(bio), start_time);
+ bdev_end_io_acct(bio->bi_bdev, bio_op(bio), sectors,
+ start_time);
if (static_branch_unlikely(&stats_enabled) &&
unlikely(dm_stats_used(&md->stats))) {
diff --git a/drivers/nvme/host/multipath.c b/drivers/nvme/host/multipath.c
index fc39d01e..9171452e 100644
--- a/drivers/nvme/host/multipath.c
+++ b/drivers/nvme/host/multipath.c
@@ -123,9 +123,8 @@ void nvme_mpath_start_request(struct request *rq)
return;
nvme_req(rq)->flags |= NVME_MPATH_IO_STATS;
- nvme_req(rq)->start_time = bdev_start_io_acct(disk->part0,
- blk_rq_bytes(rq) >> SECTOR_SHIFT,
- req_op(rq), jiffies);
+ nvme_req(rq)->start_time = bdev_start_io_acct(disk->part0, req_op(rq),
+ jiffies);
}
EXPORT_SYMBOL_GPL(nvme_mpath_start_request);
@@ -136,7 +135,8 @@ void nvme_mpath_end_request(struct request *rq)
if (!(nvme_req(rq)->flags & NVME_MPATH_IO_STATS))
return;
bdev_end_io_acct(ns->head->disk->part0, req_op(rq),
- nvme_req(rq)->start_time);
+ blk_rq_bytes(rq) >> SECTOR_SHIFT,
+ nvme_req(rq)->start_time);
}
void nvme_kick_requeue_lists(struct nvme_ctrl *ctrl)
diff --git a/include/linux/blkdev.h b/include/linux/blkdev.h
index 43d4e073..c3e06624 100644
--- a/include/linux/blkdev.h
+++ b/include/linux/blkdev.h
@@ -1434,11 +1434,10 @@ static inline void blk_wake_io_task(struct task_struct *waiter)
wake_up_process(waiter);
}
-unsigned long bdev_start_io_acct(struct block_device *bdev,
- unsigned int sectors, enum req_op op,
+unsigned long bdev_start_io_acct(struct block_device *bdev, enum req_op op,
unsigned long start_time);
void bdev_end_io_acct(struct block_device *bdev, enum req_op op,
- unsigned long start_time);
+ unsigned int sectors, unsigned long start_time);
unsigned long bio_start_io_acct(struct bio *bio);
void bio_end_io_acct_remapped(struct bio *bio, unsigned long start_time,
--
2.35.3