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dm: eliminate unused "bioset" process for each bio-based DM device
Commit 54efd50bfd
("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>
This commit is contained in:
parent
a3d939ae7b
commit
dbba42d8a9
1 changed files with 6 additions and 2 deletions
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@ -1763,8 +1763,6 @@ static void dm_make_request(struct request_queue *q, struct bio *bio)
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map = dm_get_live_table(md, &srcu_idx);
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blk_queue_split(q, &bio, q->bio_split);
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generic_start_io_acct(rw, bio_sectors(bio), &dm_disk(md)->part0);
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/* if we're suspended, we have to queue this io for later */
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@ -2792,6 +2790,12 @@ int dm_setup_md_queue(struct mapped_device *md)
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case DM_TYPE_BIO_BASED:
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dm_init_old_md_queue(md);
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blk_queue_make_request(md->queue, dm_make_request);
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/*
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* DM handles splitting bios as needed. Free the bio_split bioset
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* since it won't be used (saves 1 process per bio-based DM device).
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*/
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bioset_free(md->queue->bio_split);
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md->queue->bio_split = NULL;
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break;
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}
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