drm/virtio: notify virtqueues without holding spinlock

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Split virtqueue_kick() call into virtqueue_kick_prepare(), which
requires serialization, and virtqueue_notify(), which does not.  Move
the virtqueue_notify() call out of the critical section protected by the
queue lock.  This avoids triggering a vmexit while holding the lock and
thereby fixes a rather bad spinlock contention.

Suggested-by: Chia-I Wu <olvaffe@gmail.com>
Signed-off-by: Gerd Hoffmann <kraxel@redhat.com>
Reviewed-by: Chia-I Wu <olvaffe@gmail.com>
Link: http://patchwork.freedesktop.org/patch/msgid/20190813082509.29324-3-kraxel@redhat.com

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Gerd Hoffmann 2019-08-13 10:25:09 +02:00

parent 4100a7b834

commit 744583ecc3

1 changed files with 19 additions and 6 deletions

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drivers/gpu/drm/virtio/virtgpu_vq.c

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