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authorStefan Haberland <sth@linux.vnet.ibm.com>2016-02-12 14:50:52 +0100
committerMartin Schwidefsky <schwidefsky@de.ibm.com>2016-02-17 09:24:07 +0100
commit12d319b920fa673a4d5e7c1785c5dc82dcd15257 (patch)
treed118d395bbbe32bb3295ce739fcf63b63e45943d
parent52499d93d6dec3872de3b982219af6d4c182a452 (diff)
s390/dasd: fix performance drop
Commit ca369d51b ("sd: Fix device-imposed transfer length limits") introduced a new queue limit max_dev_sectors which limits the maximum sectors for requests. The default value leads to small dasd requests and therefor to a performance drop. Set the max_dev_sectors value to the same value as the max_hw_sectors to use the maximum available request size for DASD devices. Signed-off-by: Stefan Haberland <sth@linux.vnet.ibm.com> Cc: stable@vger.kernel.org # 4.4+ Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
-rw-r--r--drivers/s390/block/dasd.c1
1 files changed, 1 insertions, 0 deletions
diff --git a/drivers/s390/block/dasd.c b/drivers/s390/block/dasd.c
index 41605dac8309..c78db05e75b1 100644
--- a/drivers/s390/block/dasd.c
+++ b/drivers/s390/block/dasd.c
@@ -3035,6 +3035,7 @@ static void dasd_setup_queue(struct dasd_block *block)
max = block->base->discipline->max_blocks << block->s2b_shift;
}
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, block->request_queue);
+ block->request_queue->limits.max_dev_sectors = max;
blk_queue_logical_block_size(block->request_queue,
block->bp_block);
blk_queue_max_hw_sectors(block->request_queue, max);