[PATCH 0/10] Add generic helpers for arch IPI function calls #3

[Jens Axboe <jens.axboe-QHcLZuEGTsvQT0dZR+AlfA@public.gmane.org>]

Hi,

This is a repost of the generic-ipi block git branch. It contains
generic helpers for issuing and handling IPI function calls. It
improves smp_call_function_single() so that it is now a scalable
interface that doesn't rely on call_lock and it also greatly
speeds up smp_call_function(). Microbenchmarks show that it is about
30% faster on call throughput on a simple 2-way SMP system. Benefits
should be much higher on bigger systems.

Changes since last post:

- Address Andrew's review comments
- Address Paul's RCU comments. Hopefully everything is covered now,
  I'd much appreciate a second look at this code Paul!
- Drop s390 support, as it currently relies on smp_call_function()
  not returning before other CPUs are ready (or have) called the passed
  in function.
- Address the x86/xen comments from Jeremy, I hope xen works as expected
  now.
- Address the review comments from Peter.
- Various other little things and improvements.

-- 
Jens Axboe