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Drivers: hv: Implement routines for read side signaling optimization

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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: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
K. Y. Srinivasan 2012-12-01 06:46:32 -08:00 committed by Greg Kroah-Hartman
parent 0bffd25ce9
commit 6fdf3b2143
2 changed files with 28 additions and 0 deletions
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4
drivers/hv/hyperv_vmbus.h
View File

@ -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

24
drivers/hv/ring_buffer.c
View File

@ -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()