Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
os
linux
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>
+25
-8
+1
drivers/md/dm-core.h
+1
drivers/md/dm-core.h
+24
-8
drivers/md/dm.c
+24
-8
drivers/md/dm.c
···
490
490
}
491
491
EXPORT_SYMBOL_GPL(dm_start_time_ns_from_clone);
492
492
493
-
static inline bool bio_is_flush_with_data(struct bio *bio)
494
-
{
495
-
return ((bio->bi_opf & REQ_PREFLUSH) && bio->bi_iter.bi_size);
496
-
}
497
-
498
493
static inline unsigned int dm_io_sectors(struct dm_io *io, struct bio *bio)
499
494
{
500
495
/*
501
496
* If REQ_PREFLUSH set, don't account payload, it will be
502
497
* submitted (and accounted) after this flush completes.
503
498
*/
504
-
if (bio_is_flush_with_data(bio))
499
+
if (io->requeue_flush_with_data)
505
500
return 0;
506
501
if (unlikely(dm_io_flagged(io, DM_IO_WAS_SPLIT)))
507
502
return io->sectors;
···
585
590
io = container_of(tio, struct dm_io, tio);
586
591
io->magic = DM_IO_MAGIC;
587
592
io->status = BLK_STS_OK;
593
+
io->requeue_flush_with_data = false;
588
594
589
595
/* one ref is for submission, the other is for completion */
590
596
atomic_set(&io->io_count, 2);
···
944
948
struct mapped_device *md = io->md;
945
949
blk_status_t io_error;
946
950
bool requeued;
951
+
bool requeue_flush_with_data;
947
952
948
953
requeued = dm_handle_requeue(io, first_stage);
949
954
if (requeued && first_stage)
···
961
964
__dm_start_io_acct(io);
962
965
dm_end_io_acct(io);
963
966
}
967
+
requeue_flush_with_data = io->requeue_flush_with_data;
964
968
free_io(io);
965
969
smp_wmb();
966
970
this_cpu_dec(*md->pending_io);
···
974
976
if (requeued)
975
977
return;
976
978
977
-
if (bio_is_flush_with_data(bio)) {
979
+
if (unlikely(requeue_flush_with_data)) {
978
980
/*
979
981
* Preflush done for flush with data, reissue
980
982
* without REQ_PREFLUSH.
···
1994
1996
}
1995
1997
init_clone_info(&ci, io, map, bio, is_abnormal);
1996
1998
1997
-
if (bio->bi_opf & REQ_PREFLUSH) {
1999
+
if (unlikely((bio->bi_opf & REQ_PREFLUSH) != 0)) {
2000
+
/*
2001
+
* The "flush_bypasses_map" is set on targets where it is safe
2002
+
* to skip the map function and submit bios directly to the
2003
+
* underlying block devices - currently, it is set for dm-linear
2004
+
* and dm-stripe.
2005
+
*
2006
+
* If we have just one underlying device (i.e. there is one
2007
+
* linear target or multiple linear targets pointing to the same
2008
+
* device), we can send the flush with data directly to it.
2009
+
*/
2010
+
if (map->flush_bypasses_map) {
2011
+
struct list_head *devices = dm_table_get_devices(map);
2012
+
if (devices->next == devices->prev)
2013
+
goto send_preflush_with_data;
2014
+
}
2015
+
if (bio->bi_iter.bi_size)
2016
+
io->requeue_flush_with_data = true;
1998
2017
__send_empty_flush(&ci);
1999
2018
/* dm_io_complete submits any data associated with flush */
2000
2019
goto out;
2001
2020
}
2002
2021
2022
+
send_preflush_with_data:
2003
2023
if (static_branch_unlikely(&zoned_enabled) &&
2004
2024
(bio_op(bio) == REQ_OP_ZONE_RESET_ALL)) {
2005
2025
error = __send_zone_reset_all(&ci);