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(parent: 0758f4f) | patch
virtio-scsi: replace target spinlock with seqcount
authorMing Lei <ming.lei@canonical.com>
Sun, 6 Jul 2014 14:39:26 +0000 (16:39 +0200)
committerChristoph Hellwig <hch@lst.de>
Fri, 25 Jul 2014 21:17:00 +0000 (17:17 -0400)
commit938ece711c5b1ba4fa8e3b9fc8cc03843ae82a5b
treeb0e463b8a15699a1eb68f92baf3ed52200f255aatree | snapshot (tar.gz zip)
parent0758f4f732b08b6ef07f2e5f735655cf69fea477commit | diff
virtio-scsi: replace target spinlock with seqcount

The spinlock of tgt_lock is only for serializing read and write
req_vq, one lockless seqcount is enough for the purpose.

On one 16core VM with vhost-scsi backend, the patch can improve
IOPS with 3% on random read test.

Signed-off-by: Ming Lei <ming.lei@canonical.com>
[Add initialization in virtscsi_target_alloc. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
drivers/scsi/virtio_scsi.c diff | blob | blame | history