Files
linux/kernel
Hidetoshi Seto c5f8d99585 posixtimers, sched: Fix posix clock monotonicity
Impact: Regression fix (against clock_gettime() backwarding bug)

This patch re-introduces a couple of functions, task_sched_runtime
and thread_group_sched_runtime, which was once removed at the
time of 2.6.28-rc1.

These functions protect the sampling of thread/process clock with
rq lock.  This rq lock is required not to update rq->clock during
the sampling.

i.e.
  The clock_gettime() may return
   ((accounted runtime before update) + (delta after update))
  that is less than what it should be.

v2 -> v3:
	- Rename static helper function __task_delta_exec()
	  to do_task_delta_exec() since -tip tree already has
	  a __task_delta_exec() of different version.

v1 -> v2:
	- Revises comments of function and patch description.
	- Add note about accuracy of thread group's runtime.

Signed-off-by: Hidetoshi Seto <seto.hidetoshi@jp.fujitsu.com>
Acked-by: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: stable@kernel.org	[2.6.28.x][2.6.29.x]
LKML-Reference: <49D1CC93.4080401@jp.fujitsu.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
2009-04-01 16:44:16 +02:00
..
2009-02-05 12:56:46 -08:00
2008-10-16 11:21:30 -07:00
2008-07-28 14:37:38 +02:00
2009-01-06 15:59:27 -08:00
2008-12-10 08:01:54 -08:00
2009-01-14 18:09:02 +01:00
2009-01-08 08:31:02 -08:00
2009-01-08 08:31:12 -08:00
2008-09-02 19:21:40 -07:00
2009-02-01 10:49:51 +01:00
2008-10-16 11:21:47 -07:00