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Commit 6fdf3b21 authored by K. Y. Srinivasan's avatar K. Y. Srinivasan Committed by Greg Kroah-Hartman
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Drivers: hv: Implement routines for read side signaling optimization 



Implement functions that will support read-side signaling optimization.
By having the reader indicate the start of the "read" operation and the
"end" of the read operation we can more efficiently handle the signaling
protocol: while the read is in progress, there is no need for the "writer"
to signal the "reader" as new items are put on the read queue.

Signed-off-by: default avatarK. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: default avatarHaiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 0bffd25c

drivers/hv/hyperv_vmbus.h

+4 −0
Original line number Diff line number Diff line
@@ -570,6 +570,10 @@ u32 hv_get_ringbuffer_interrupt_mask(struct hv_ring_buffer_info *ring_info); 
void hv_ringbuffer_get_debuginfo(struct hv_ring_buffer_info *ring_info,

			    struct hv_ring_buffer_debug_info *debug_info);



void hv_begin_read(struct hv_ring_buffer_info *rbi);



u32 hv_end_read(struct hv_ring_buffer_info *rbi);



/*

 * Maximum channels is determined by the size of the interrupt page

 * which is PAGE_SIZE. 1/2 of PAGE_SIZE is for send endpoint interrupt

drivers/hv/ring_buffer.c

+24 −0
Original line number Diff line number Diff line
@@ -29,6 +29,30 @@ 


#include "hyperv_vmbus.h"



void hv_begin_read(struct hv_ring_buffer_info *rbi)

{

	rbi->ring_buffer->interrupt_mask = 1;

	smp_mb();

}



u32 hv_end_read(struct hv_ring_buffer_info *rbi)

{

	u32 read;

	u32 write;



	rbi->ring_buffer->interrupt_mask = 0;

	smp_mb();



	/*

	 * Now check to see if the ring buffer is still empty.

	 * If it is not, we raced and we need to process new

	 * incoming messages.

	 */

	hv_get_ringbuffer_availbytes(rbi, &read, &write);



	return read;

}





/*

 * hv_get_next_write_location()