diff options
| author | K. Y. Srinivasan <kys@microsoft.com> | 2012-12-01 06:46:32 -0800 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-17 10:46:39 -0800 |
| commit | 6fdf3b21433e901dcba0ac186f00d604ce944f56 (patch) | |
| tree | 57ba241493d522388a1d8eda8663f43c96b57f32 | |
| parent | 0bffd25ce919f88ea6473150b66d26e7fa5712af (diff) | |
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: K. Y. Srinivasan <kys@microsoft.com>
Reviewed-by: Haiyang Zhang <haiyangz@microsoft.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
| -rw-r--r-- | drivers/hv/hyperv_vmbus.h | 4 | ||||
| -rw-r--r-- | drivers/hv/ring_buffer.c | 24 |
2 files changed, 28 insertions, 0 deletions
diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h index d8d1fadb398a..3184f6ff4e74 100644 --- a/drivers/hv/hyperv_vmbus.h +++ b/drivers/hv/hyperv_vmbus.h @@ -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 diff --git a/drivers/hv/ring_buffer.c b/drivers/hv/ring_buffer.c index 7233c88f01b8..001079287709 100644 --- a/drivers/hv/ring_buffer.c +++ b/drivers/hv/ring_buffer.c @@ -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() |