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| author | Mikulas Patocka <mpatocka@redhat.com> | 2025-09-15 17:42:45 +0200 |
|---|---|---|
| committer | Mikulas Patocka <mpatocka@redhat.com> | 2025-09-18 12:58:02 +0200 |
| commit | 2b1c6d7a890aeaeabfeabd1cef5a4808043dc1a4 (patch) | |
| tree | b9990efef1c283b9e33916b34aa75c2761b65e7c | |
| parent | 4466dd3d719cca113308e8ae539adf7b3d68c985 (diff) | |
| download | linux-2b1c6d7a890a.tar.gz | |
dm: optimize REQ_PREFLUSH with data when using the linear target
If the table has only linear targets and there is just one underlying
device, we can optimize REQ_PREFLUSH with data - we don't have to split
it to two bios - a flush and a write. We can pass it to the linear target
directly.
Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Tested-by: Bart Van Assche <bvanassche@acm.org>
Reviewed-by: Bart Van Assche <bvanassche@acm.org>
| -rw-r--r-- | drivers/md/dm-core.h | 1 | ||||
| -rw-r--r-- | drivers/md/dm.c | 32 |
2 files changed, 25 insertions, 8 deletions
diff --git a/drivers/md/dm-core.h b/drivers/md/dm-core.h index 0070e4462ee2fe..a3c9f74fe2dc47 100644 --- a/drivers/md/dm-core.h +++ b/drivers/md/dm-core.h @@ -292,6 +292,7 @@ struct dm_io { struct dm_io *next; struct dm_stats_aux stats_aux; blk_status_t status; + bool requeue_flush_with_data; atomic_t io_count; struct mapped_device *md; diff --git a/drivers/md/dm.c b/drivers/md/dm.c index 66dd5f6ce778b6..3ede5ba4cf7ece 100644 --- a/drivers/md/dm.c +++ b/drivers/md/dm.c @@ -490,18 +490,13 @@ u64 dm_start_time_ns_from_clone(struct bio *bio) } EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone); -static inline bool bio_is_flush_with_data(struct bio *bio) -{ - return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size); -} - static inline unsigned int dm_io_sectors(struct dm_io *io, struct bio *bio) { /* * If REQ_PREFLUSH set, don't account payload, it will be * submitted (and accounted) after this flush completes. */ - if (bio_is_flush_with_data(bio)) + if (io->requeue_flush_with_data) return 0; if (unlikely(dm_io_flagged(io, DM_IO_WAS_SPLIT))) return io->sectors; @@ -590,6 +585,7 @@ static struct dm_io *alloc_io(struct mapped_device *md, struct bio *bio, gfp_t g io = container_of(tio, struct dm_io, tio); io->magic = DM_IO_MAGIC; io->status = BLK_STS_OK; + io->requeue_flush_with_data = false; /* one ref is for submission, the other is for completion */ atomic_set(&io->io_count, 2); @@ -948,6 +944,7 @@ static void __dm_io_complete(struct dm_io *io, bool first_stage) struct mapped_device *md = io->md; blk_status_t io_error; bool requeued; + bool requeue_flush_with_data; requeued = dm_handle_requeue(io, first_stage); if (requeued && first_stage) @@ -964,6 +961,7 @@ static void __dm_io_complete(struct dm_io *io, bool first_stage) __dm_start_io_acct(io); dm_end_io_acct(io); } + requeue_flush_with_data = io->requeue_flush_with_data; free_io(io); smp_wmb(); this_cpu_dec(*md->pending_io); @@ -976,7 +974,7 @@ static void __dm_io_complete(struct dm_io *io, bool first_stage) if (requeued) return; - if (bio_is_flush_with_data(bio)) { + if (unlikely(requeue_flush_with_data)) { /* * Preflush done for flush with data, reissue * without REQ_PREFLUSH. @@ -1996,12 +1994,30 @@ static void dm_split_and_process_bio(struct mapped_device *md, } init_clone_info(&ci, io, map, bio, is_abnormal); - if (bio->bi_opf & REQ_PREFLUSH) { + if (unlikely((bio->bi_opf & REQ_PREFLUSH) != 0)) { + /* + * The "flush_bypasses_map" is set on targets where it is safe + * to skip the map function and submit bios directly to the + * underlying block devices - currently, it is set for dm-linear + * and dm-stripe. + * + * If we have just one underlying device (i.e. there is one + * linear target or multiple linear targets pointing to the same + * device), we can send the flush with data directly to it. + */ + if (map->flush_bypasses_map) { + struct list_head *devices = dm_table_get_devices(map); + if (devices->next == devices->prev) + goto send_preflush_with_data; + } + if (bio->bi_iter.bi_size) + io->requeue_flush_with_data = true; __send_empty_flush(&ci); /* dm_io_complete submits any data associated with flush */ goto out; } +send_preflush_with_data: if (static_branch_unlikely(&zoned_enabled) && (bio_op(bio) == REQ_OP_ZONE_RESET_ALL)) { error = __send_zone_reset_all(&ci); |