AcoSail/kernel_optimize_test
8
0
Fork 0
forked from luck/tmp_suning_uos_patched
Code Pull Requests Activity

sched/isolation: Make CONFIG_NO_HZ_FULL select CONFIG_CPU_ISOLATION

Browse Source 
CONFIG_NO_HZ_FULL doesn't make sense without CONFIG_CPU_ISOLATION. In
fact enabling the first without the second is a regression as nohz_full=
boot parameter gets silently ignored.

Besides this unnatural combination hangs RCU gp kthread when running
rcutorture for reasons that are not yet fully understood:

	rcu_preempt kthread starved for 9974 jiffies! g4294967208
	+c4294967207 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=0
	rcu_preempt     I 7464     8      2 0x80000000
	Call Trace:
		__schedule+0x493/0x620
		schedule+0x24/0x40
		schedule_timeout+0x330/0x3b0
		? preempt_count_sub+0xea/0x140
		? collect_expired_timers+0xb0/0xb0
		rcu_gp_kthread+0x6bf/0xef0

This commit therefore makes NO_HZ_FULL select CPU_ISOLATION, which
prevents all these bad behaviours.

Reported-by: kernel test robot <xiaolong.ye@intel.com>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Signed-off-by: Frederic Weisbecker <frederic@kernel.org>
Cc: Chris Metcalf <cmetcalf@mellanox.com>
Cc: Christoph Lameter <cl@linux.com>
Cc: John Stultz <john.stultz@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Luiz Capitulino <lcapitulino@redhat.com>
Cc: Mike Galbraith <efault@gmx.de>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Wanpeng Li <kernellwp@gmail.com>
Fixes: 5c4991e24c ("sched/isolation: Split out new CONFIG_CPU_ISOLATION=y config from CONFIG_NO_HZ_FULL")
Link: http://lkml.kernel.org/r/1513275507-29200-2-git-send-email-frederic@kernel.org
Signed-off-by: Ingo Molnar <mingo@kernel.org>
This commit is contained in:
Paul E. McKenney 2017-12-14 19:18:25 +01:00 committed by Ingo Molnar
parent 1291a0d504
commit bf29cb238d
1 changed files with 1 additions and 0 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

1
kernel/time/Kconfig
View File

@ -95,6 +95,7 @@ config NO_HZ_FULL
select RCU_NOCB_CPU select RCU_NOCB_CPU
select VIRT_CPU_ACCOUNTING_GEN select VIRT_CPU_ACCOUNTING_GEN
select IRQ_WORK select IRQ_WORK
select CPU_ISOLATION
help help
Adaptively try to shutdown the tick whenever possible, even when Adaptively try to shutdown the tick whenever possible, even when
the CPU is running tasks. Typically this requires running a single the CPU is running tasks. Typically this requires running a single