[PATCH] sched: cleanup, improve sched <=> fork APIs

[PATCH] sched: cleanup, improve sched <=> fork APIs

Move balancing and child-runs-first logic from fork.c into sched.c where
it belongs.

* Consolidate wake_up_forked_process and wake_up_forked_thread into
  wake_up_new_process, and pass in clone_flags as suggested by Linus.  This
  removes a lot of code duplication and allows all logic to be handled in that
  function.

* Don't do balance-on-clone balancing for vfork'ed threads.

* Don't do set_task_cpu or balance one clone in wake_up_new_process.
  Instead do it in sched_fork to fix set_cpus_allowed races.

* Don't do child-runs-first for CLONE_VM processes, as there is obviously no
  COW benifit to be had.  This is a big one, it enables Andi's workload to run
  well without clone balancing, because the OpenMP child threads can get
  balanced off to other nodes *before* they start running and allocating
  memory.

* Rename sched_balance_exec to sched_exec: hide the policy from the API.

From: Ingo Molnar <mingo@elte.hu>

  rename wake_up_new_process -> wake_up_new_task.

  in sched.c we are gradually moving away from the overloaded 'process' or
  'thread' notion to the traditional task (or context) naming.

Signed-off-by: Nick Piggin <nickpiggin@yahoo.com.au>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
Signed-off-by: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>