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authorK. Y. Srinivasan <kys@microsoft.com>2012-12-01 06:46:32 -0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2013-01-17 10:46:39 -0800
commit6fdf3b21433e901dcba0ac186f00d604ce944f56 (patch)
tree57ba241493d522388a1d8eda8663f43c96b57f32 /drivers/hv/ring_buffer.c
parent0bffd25ce919f88ea6473150b66d26e7fa5712af (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>
Diffstat (limited to 'drivers/hv/ring_buffer.c')
-rw-r--r--drivers/hv/ring_buffer.c24
1 files changed, 24 insertions, 0 deletions
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()

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