Wanpeng Li 444969223c sched/nohz: Fix affine unpinned timers mess
The following commit:

  9642d18eee2c ("nohz: Affine unpinned timers to housekeepers")'

intended to affine unpinned timers to housekeepers:

  unpinned timers(full dynaticks, idle)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(full dynaticks, busy)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(houserkeepers, idle)    =>   nearest busy housekeepers(otherwise, fallback to itself)

However, the !idle_cpu(i) && is_housekeeping_cpu(cpu) check modified the
intention to:

  unpinned timers(full dynaticks, idle)   =>   any housekeepers(no mattter cpu topology)
  unpinned timers(full dynaticks, busy)   =>   any housekeepers(no mattter cpu topology)
  unpinned timers(housekeepers, idle)     =>   any busy cpus(otherwise, fallback to any housekeepers)

This patch fixes it by checking if there are busy housekeepers nearby,
otherwise falls to any housekeepers/itself. After the patch:

  unpinned timers(full dynaticks, idle)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(full dynaticks, busy)   =>   nearest busy housekeepers(otherwise, fallback to any housekeepers)
  unpinned timers(housekeepers, idle)     =>   nearest busy housekeepers(otherwise, fallback to itself)

Signed-off-by: Wanpeng Li <wanpeng.li@hotmail.com>
Signed-off-by: Peter Zijlstra (Intel) <peterz@infradead.org>
[ Fixed the changelog. ]
Cc: Frederic Weisbecker <fweisbec@gmail.com>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-kernel@vger.kernel.org
Fixes: 'commit 9642d18eee2c ("nohz: Affine unpinned timers to housekeepers")'
Link: http://lkml.kernel.org/r/1462344334-8303-1-git-send-email-wanpeng.li@hotmail.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
2016-05-12 09:55:32 +02:00
..
2015-12-04 22:46:25 +01:00
2016-03-22 15:36:02 -07:00
2015-04-11 22:27:55 -04:00
2015-11-19 17:51:48 +01:00
2016-01-22 18:04:28 -05:00
2016-02-08 11:25:39 -05:00
2014-08-08 15:57:18 -07:00
2015-12-14 14:54:37 -05:00
2015-04-12 21:03:31 +02:00
2016-03-22 15:36:02 -07:00
2015-11-23 09:44:58 +01:00
2016-04-28 19:34:04 -07:00
2016-03-22 15:36:02 -07:00
2016-03-22 15:36:02 -07:00
2016-02-16 13:04:58 -05:00
2015-01-17 10:02:23 +13:00
2016-01-22 18:04:28 -05:00
2016-03-01 20:36:56 +01:00