From b2676e1482af89714af6988ce5d31a84692e2530 Mon Sep 17 00:00:00 2001 From: Mikulas Patocka Date: Mon, 11 Jul 2022 16:31:26 -0400 Subject: [PATCH] dm writecache: count number of blocks written, not number of write bios Change dm-writecache, so that it counts the number of blocks written instead of the number of write bios. Bios can be split and requeued using the dm_accept_partial_bio function, so counting bios caused inaccurate results. Fixes: e3a35d03407c ("dm writecache: add event counters") Reported-by: Yu Kuai Signed-off-by: Mikulas Patocka Signed-off-by: Mike Snitzer --- .../admin-guide/device-mapper/writecache.rst | 10 +++++----- drivers/md/dm-writecache.c | 12 +++++++++--- 2 files changed, 14 insertions(+), 8 deletions(-) diff --git a/Documentation/admin-guide/device-mapper/writecache.rst b/Documentation/admin-guide/device-mapper/writecache.rst index 1fab82408ef1..0772d2160f9c 100644 --- a/Documentation/admin-guide/device-mapper/writecache.rst +++ b/Documentation/admin-guide/device-mapper/writecache.rst @@ -82,11 +82,11 @@ Status: 4. the number of blocks under writeback 5. the number of read blocks 6. the number of read blocks that hit the cache -7. the number of write requests -8. the number of write requests that hit uncommitted block -9. the number of write requests that hit committed block -10. the number of write requests that bypass the cache -11. the number of write requests that are allocated in the cache +7. the number of write blocks +8. the number of write blocks that hit uncommitted block +9. the number of write blocks that hit committed block +10. the number of write blocks that bypass the cache +11. the number of write blocks that are allocated in the cache 12. the number of write requests that are blocked on the freelist 13. the number of flush requests 14. the number of discard requests diff --git a/drivers/md/dm-writecache.c b/drivers/md/dm-writecache.c index a551be5f9b4b..6282c77abe7b 100644 --- a/drivers/md/dm-writecache.c +++ b/drivers/md/dm-writecache.c @@ -1413,6 +1413,9 @@ static void writecache_bio_copy_ssd(struct dm_writecache *wc, struct bio *bio, bio->bi_iter.bi_sector = start_cache_sec; dm_accept_partial_bio(bio, bio_size >> SECTOR_SHIFT); + wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits; + wc->stats.writes_allocate += (bio->bi_iter.bi_size - wc->block_size) >> wc->block_size_bits; + if (unlikely(wc->uncommitted_blocks >= wc->autocommit_blocks)) { wc->uncommitted_blocks = 0; queue_work(wc->writeback_wq, &wc->flush_work); @@ -1428,9 +1431,10 @@ static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio do { bool found_entry = false; bool search_used = false; - wc->stats.writes++; - if (writecache_has_error(wc)) + if (writecache_has_error(wc)) { + wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits; return WC_MAP_ERROR; + } e = writecache_find_entry(wc, bio->bi_iter.bi_sector, 0); if (e) { if (!writecache_entry_is_committed(wc, e)) { @@ -1454,9 +1458,10 @@ static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio if (unlikely(!e)) { if (!WC_MODE_PMEM(wc) && !found_entry) { direct_write: - wc->stats.writes_around++; e = writecache_find_entry(wc, bio->bi_iter.bi_sector, WFE_RETURN_FOLLOWING); writecache_map_remap_origin(wc, bio, e); + wc->stats.writes_around += bio->bi_iter.bi_size >> wc->block_size_bits; + wc->stats.writes += bio->bi_iter.bi_size >> wc->block_size_bits; return WC_MAP_REMAP_ORIGIN; } wc->stats.writes_blocked_on_freelist++; @@ -1470,6 +1475,7 @@ static enum wc_map_op writecache_map_write(struct dm_writecache *wc, struct bio bio_copy: if (WC_MODE_PMEM(wc)) { bio_copy_block(wc, bio, memory_data(wc, e)); + wc->stats.writes++; } else { writecache_bio_copy_ssd(wc, bio, e, search_used); return WC_MAP_REMAP;