Closing a perf fd can also trigger an IPI to the target CPU.

Use the same affinity technique as we use for reading/enabling events to
closing to optimize the CPU transitions.

Before on a large test case with 94 CPUs:

  % time     seconds  usecs/call     calls    errors syscall
  ------ ----------- ----------- --------- --------- ----------------
   32.56    3.085463          50     61483           close

  After:

   10.54    0.735704          11     61485           close
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Acked-by: NJiri Olsa <jolsa@kernel.org>
Link: http://lore.kernel.org/lkml/20191121001522.180827-8-andi@firstfloor.orgSigned-off-by: NArnaldo Carvalho de Melo <acme@redhat.com>