K. Y.,
I'd like to accompany your netvsc performance improvement work by making
in-place consumption of VMBus packets always possible. Currently we forbid
it when a packet 'wraps around' the ring so we can't provide a single
pointer to it.
The idea if this series is dead simple: let's make a single virtual mapping
for two copies (actually, two sets of pages which consist the ring buffer)
of the ring buffer. With such a mapping we can always provide a pointers
for in-place consumption to drivers. Copy path can also benefit from such
mappings as we eliminate the need for conditional checking in copy_to/
copy_from functions and use a single memcpy().
Lightly tested with 'netvsc: Use the new in-place consumption APIs in the
rx path' patch and with storvsc driver.
Vitaly Kuznetsov (4):
Drivers: hv: cleanup vmbus_open() for wrap around mappings
Drivers: hv: ring_buffer: wrap around mappings for ring buffers
Drivers: hv: ring_buffer: use wrap around mappings in
hv_copy{from,to}_ringbuffer()
Drivers: hv: ring_buffer: count on wrap around mappings in
get_next_pkt_raw()
drivers/hv/channel.c | 68 ++++++++++++++++++++++++-----------------------
drivers/hv/hyperv_vmbus.h | 4 +--
drivers/hv/ring_buffer.c | 61 ++++++++++++++++++++++++------------------
include/linux/hyperv.h | 32 ++++++++--------------
4 files changed, 83 insertions(+), 82 deletions(-)
--
2.5.5
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