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Commit 15e1674d authored by Stephen Hemminger's avatar Stephen Hemminger Committed by Greg Kroah-Hartman
Browse files

vmbus: add prefetch to ring buffer iterator 



When iterating over incoming ring elements from the host, prefetch
the next descriptor so that it is cache hot.

Signed-off-by: default avatarStephen Hemminger <sthemmin@microsoft.com>
Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 03bad714

drivers/hv/ring_buffer.c

+6 −1
Original line number Diff line number Diff line
@@ -357,11 +357,16 @@ static u32 hv_pkt_iter_avail(const struct hv_ring_buffer_info *rbi) 
struct vmpacket_descriptor *hv_pkt_iter_first(struct vmbus_channel *channel)

{

	struct hv_ring_buffer_info *rbi = &channel->inbound;

	struct vmpacket_descriptor *desc;



	if (hv_pkt_iter_avail(rbi) < sizeof(struct vmpacket_descriptor))

		return NULL;



	return hv_get_ring_buffer(rbi) + rbi->priv_read_index;

	desc = hv_get_ring_buffer(rbi) + rbi->priv_read_index;

	if (desc)

		prefetch((char *)desc + (desc->len8 << 3));



	return desc;

}

EXPORT_SYMBOL_GPL(hv_pkt_iter_first);