linux-kernel - [RFC GIT PULL] sched; Fix a few missing rq clock updates

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Date:	Fri, 12 Apr 2013 01:50:57 +0200
From:	Frederic Weisbecker <fweisbec@...il.com>
To:	Ingo Molnar <mingo@...nel.org>
Cc:	LKML <linux-kernel@...r.kernel.org>,
	Frederic Weisbecker <fweisbec@...il.com>,
	Li Zhong <zhong@...ux.vnet.ibm.com>,
	Peter Zijlstra <peterz@...radead.org>,
	Steven Rostedt <rostedt@...dmis.org>,
	Thomas Gleixner <tglx@...utronix.de>,
	Paul Turner <pjt@...gle.com>, Mike Galbraith <efault@....de>
Subject: [RFC GIT PULL] sched; Fix a few missing rq clock updates

Hi,

So I revisited the rq clock series I had for dynticks. The patches
actually were about upstream issues so I refactored the fixes
under that angle and gave up with the wrong asumption that rq
clock relies on the tick for its updates.

Patches 1-4 fix some missing updates. Additionally I removed
2 of these updates from the previous set:

* No need to update the rq clock on idle_balance() because it should
follow a call to deactivate_task() (unless TIF_NEED_RESCHED is set
on idle without new task on the runqueue, not sure we want to cover that).

* No need to update for try_to_wake_up_local() -> ttwu_do_wakeup() -> check_preempt_curr()
  as it's following deactivate_task().

Patch 5 brings accessors that will be necessary to settle an rq clock
debugging engine. What remains is to tag scheduler's entry/exit points
and report missing or redundant update_rq_clock() before calls to
rq_clock() and rq_clock_task().

The branch is pullable from:

git://git.kernel.org/pub/scm/linux/kernel/git/frederic/linux-dynticks.git
	sched/core

HEAD: 8b5fa0f1de7e41176dc68740de7548110a404538

Thanks.

---
Frederic Weisbecker (5):
  sched: Update rq clock before migrating tasks out of dying CPU
  sched: Update rq clock before setting fair group shares
  sched: Update rq clock before calling check_preempt_curr()
  sched: Update rq clock earlier in unthrottle_cfs_rq
  sched: Use an accessor to read rq clock

 kernel/sched/core.c      |   15 ++++++++++--
 kernel/sched/fair.c      |   51 +++++++++++++++++++++++++--------------------
 kernel/sched/rt.c        |    8 +++---
 kernel/sched/sched.h     |   10 +++++++++
 kernel/sched/stats.h     |    8 +++---
 kernel/sched/stop_task.c |    8 +++---
 6 files changed, 62 insertions(+), 38 deletions(-)

-- 
1.7.5.4

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