tree 521700786b60a52c5531654b0e30f24c062abe97
parent d979534274183c9bb69efa4950be956028f9ae7a
author Andi Kleen <ak@linux.intel.com> 1442621734 -0700
committer Andi Kleen <ak@linux.intel.com> 1455303529 -0800

random: Make input to output pool balancing per cpu

The load balancing from input pool to output pools was
essentially unlocked. Before it didn't matter much because
there were only two choices (blocking and non blocking).

But now with the distributed non blocking pools we have
a lot more pools, and unlocked access of the counters
may systematically deprive some nodes from their deserved
entropy.

Turn the round-robin state into per CPU variables
to avoid any possibility of races. This code already
runs with preemption disabled.

v2: Check for non initialized pools.
v3: Make per cpu variables global to avoid warnings in some
configurations (0day)

Signed-off-by: Andi Kleen <ak@linux.intel.com>

squash! Make /dev/urandom scalable