dm: eliminate unused "bioset" process for each bio-based DM device
authorMikulas Patocka <mpatocka@redhat.com>
Wed, 21 Oct 2015 20:34:20 +0000 (16:34 -0400)
committerMike Snitzer <snitzer@redhat.com>
Sat, 31 Oct 2015 23:06:02 +0000 (19:06 -0400)
commitdbba42d8a9ebddcc1c1412e8457f79f3cb6ef6e7
treeaa185bdeae4a2b11d875cb2a21dac8c23608e1bf
parenta3d939ae7b5f82688a6d3450f95286eaea338328
dm: eliminate unused "bioset" process for each bio-based DM device

Commit 54efd50bfd873e2dbf784e0b21a8027ba4299a3e ("block: make
generic_make_request handle arbitrarily sized bios") makes it possible
for block devices to process large bios.  In doing so that commit
allocates a new queue->bio_split bioset for each block device, this
bioset is used for allocating bios when the driver needs to split large
bios.

Each bioset allocates a workqueue process, thus the above commit
increases the number of processes allocated per block device.

DM doesn't need the queue->bio_split bioset, thus we can deallocate it.
This reduces the number of allocated processes per bio-based DM device
from 3 to 2.  Also remove the call to blk_queue_split(), it is not
needed because DM does its own splitting.

Signed-off-by: Mikulas Patocka <mpatocka@redhat.com>
Signed-off-by: Mike Snitzer <snitzer@redhat.com>
drivers/md/dm.c