Running the page-pool sample on production machines under moderate
networking load shows recycling rate higher than 100%:
$ page-pool
eth0[2] page pools: 14 (zombies: 0)
refs: 89088 bytes: 364904448 (refs: 0 bytes: 0)
recycling: 100.3% (alloc: 1392:2290247724 recycle: 469289484:1828235386)
Note that outstanding refs (89088) == slow alloc * cache size (1392 * 64)
which means this machine is recycling page pool pages perfectly, not
a single page has been released.
The extra 0.3% is because sample ignores allocations from the ptr_ring.
Treat those the same as alloc_fast, the ring vs cache alloc is
already captured accurately enough by recycling stats.
With the fix:
$ page-pool
eth0[2] page pools: 14 (zombies: 0)
refs: 89088 bytes: 364904448 (refs: 0 bytes: 0)
recycling: 100.0% (alloc: 1392:2331141604 recycle: 473625579:1857460661)
Signed-off-by: Jakub Kicinski <kuba@kernel.org>
Signed-off-by: David S. Miller <davem@davemloft.net>
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