net: thunderx: Optimize page recycling for XDP

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Driver follows a method of taking one extra reference on the
page for recycling which is fine in usual packet path where
each 64KB page is segmented into multiple receive buffers.

But in XDP mode since there is just one receive buffer per
page taking extra page reference itself becomes big bottleneck
consuming ~50% of CPU cycles due to atomic operations.

This patch adds a internal ref count in pgcache for each
page and additional page references are taken in a batch
instead of just one at a time. Internal i.e 'pgcache->ref_count'
and page's i.e 'page->_refcount' counters are compared to check
page's recyclability.

Signed-off-by: Sunil Goutham <sgoutham@cavium.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

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This commit is contained in:

Sunil Goutham 2017-05-02 18:36:58 +05:30 • committed by David S. Miller

parent e3d06ff9ec

commit 773225388d

2 changed files with 51 additions and 7 deletions

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51

drivers/net/ethernet/cavium/thunder/nicvf_queues.c

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1

drivers/net/ethernet/cavium/thunder/nicvf_queues.h

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