xen-blkfront: make blkif_io_lock spinlock per-device

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This patch moves the global blkif_io_lock to the per-device structure. The
spinlock seems to exists for two reasons: to disable IRQs when in the interrupt
handlers for blkfront, and to protect the blkfront VBDs when a detachment is
requested.

Having a global blkif_io_lock doesn't make sense given the use case, and it
drastically hinders performance due to contention. All VBDs with pending IOs
have to take the lock in order to get work done, which serializes everything
pretty badly.

Signed-off-by: Steven Noonan <snoonan@amazon.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

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Steven Noonan 2012-02-17 12:04:44 -08:00 • committed by Jens Axboe

parent dad5cf659b

commit 3467811e26

1 changed files with 16 additions and 16 deletions

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drivers/block/xen-blkfront.c

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