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author | K. Y. Srinivasan <kys@microsoft.com> | 2012-12-01 06:46:32 -0800 |
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committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2013-01-17 10:46:39 -0800 |
commit | 6fdf3b21433e901dcba0ac186f00d604ce944f56 (patch) | |
tree | 57ba241493d522388a1d8eda8663f43c96b57f32 /drivers/hv/ring_buffer.c | |
parent | 0bffd25ce919f88ea6473150b66d26e7fa5712af (diff) | |
download | linux-6fdf3b21433e901dcba0ac186f00d604ce944f56.tar.gz linux-6fdf3b21433e901dcba0ac186f00d604ce944f56.tar.bz2 linux-6fdf3b21433e901dcba0ac186f00d604ce944f56.zip |
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.c | 24 |
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() |