linux-toradex.git/kernel/time/Kconfig, branch v5.1-rc1

time: Move CONTEXT_TRACKING to kernel/time/Kconfig

2019-01-15T10:16:41+00:00

Both CONTEXT_TRACKING and CONTEXT_TRACKING_FORCE are currently defined
in kernel/rcu/kconfig, which might have made sense at some point, but
no longer does given that RCU refers to neither of these Kconfig options.

Therefore move them to kernel/time/Kconfig, where the rest of the
NO_HZ_FULL Kconfig options live.

Signed-off-by: Paul E. McKenney 
Signed-off-by: Thomas Gleixner 
Cc: Frederic Weisbecker 
Link: https://lkml.kernel.org/r/20181220170525.GA12579@linux.ibm.com

clocksource: Provide clocksource_arch_init()

2018-10-04T21:00:24+00:00

Architectures have extra archdata in the clocksource, e.g. for VDSO
support. There are no sanity checks or general initializations for this
available. Add support for that.

Signed-off-by: Thomas Gleixner 
Acked-by: Andy Lutomirski 
Acked-by: John Stultz 
Cc: Peter Zijlstra 
Cc: Matt Rickard 
Cc: Stephen Boyd 
Cc: Florian Weimer 
Cc: "K. Y. Srinivasan" 
Cc: Vitaly Kuznetsov 
Cc: devel@linuxdriverproject.org
Cc: virtualization@lists.linux-foundation.org
Cc: Paolo Bonzini 
Cc: Arnd Bergmann 
Cc: Juergen Gross 
Link: https://lkml.kernel.org/r/20180917130706.973042587@linutronix.de

sched/isolation: Eliminate NO_HZ_FULL_ALL

2018-02-15T23:40:37+00:00

Commit 6f1982fedd59 ("sched/isolation: Handle the nohz_full= parameter")
broke CONFIG_NO_HZ_FULL_ALL=y kernels.  This breakage is due to the code
under CONFIG_NO_HZ_FULL_ALL failing to invoke the shiny new housekeeping
functions.  This means that rcutorture scenario TREE04 now emits RCU CPU
stall warnings due to the RCU grace-period kthreads not being awakened
at a time of their choosing, or perhaps even not at all:

[   27.731422] rcu_bh kthread starved for 21001 jiffies! g18446744073709551369 c18446744073709551368 f0x0 RCU_GP_WAIT_FQS(3) ->state=0x402 ->cpu=3
[   27.731423] rcu_bh          I14936     9      2 0x80080000
[   27.731435] Call Trace:
[   27.731440]  __schedule+0x31a/0x6d0
[   27.731442]  schedule+0x31/0x80
[   27.731446]  schedule_timeout+0x15a/0x320
[   27.731453]  ? call_timer_fn+0x130/0x130
[   27.731457]  rcu_gp_kthread+0x66c/0xea0
[   27.731458]  ? rcu_gp_kthread+0x66c/0xea0

Because no one has complained about CONFIG_NO_HZ_FULL_ALL=y being broken,
I hypothesize that no one is in fact using it, other than rcutorture.
This commit therefore eliminates CONFIG_NO_HZ_FULL_ALL and updates
rcutorture's config files to instead use the nohz_full= kernel parameter
to put the desired CPUs into nohz_full mode.

Fixes: 6f1982fedd59 ("sched/isolation: Handle the nohz_full= parameter")

Reported-by: kernel test robot 
Signed-off-by: Paul E. McKenney 
Cc: Frederic Weisbecker 
Cc: Thomas Gleixner 
Cc: Chris Metcalf 
Cc: Christoph Lameter 
Cc: Linus Torvalds 
Cc: Luiz Capitulino 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Wanpeng Li 
Cc: Ingo Molnar 
Cc: John Stultz 
Cc: Jonathan Corbet

sched/isolation: Make CONFIG_NO_HZ_FULL select CONFIG_CPU_ISOLATION

2017-12-18T12:46:42+00:00

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 
Signed-off-by: Paul E. McKenney 
Signed-off-by: Frederic Weisbecker 
Cc: Chris Metcalf 
Cc: Christoph Lameter 
Cc: John Stultz 
Cc: Linus Torvalds 
Cc: Luiz Capitulino 
Cc: Mike Galbraith 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Thomas Gleixner 
Cc: Wanpeng Li 
Fixes: 5c4991e24c69 ("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

timekeeping: Remove CONFIG_GENERIC_TIME_VSYSCALL_OLD

2017-11-14T10:20:25+00:00

As of d4d1fc61eb38f (ia64: Update fsyscall gettime to use modern
vsyscall_update)the last user of CONFIG_GENERIC_TIME_VSYSCALL_OLD
have been updated, the legacy support for old-style vsyscall
implementations can be removed from the timekeeping code.

(Thanks again to Tony Luck for helping remove the last user!)

[jstultz: Commit message rework]

Signed-off-by: Miroslav Lichvar 
Signed-off-by: John Stultz 
Signed-off-by: Thomas Gleixner 
Cc: Prarit Bhargava 
Cc: Tony Luck 
Cc: Richard Cochran 
Cc: Stephen Boyd 
Link: https://lkml.kernel.org/r/1510613491-16695-1-git-send-email-john.stultz@linaro.org

kernel/time/Kconfig: Fix typo in comment

2017-11-02T11:50:34+00:00

Fix typo in Kconfig comment text.

Signed-off-by: Randy Dunlap 
Signed-off-by: Thomas Gleixner 
Cc: John Stultz 
Cc: Stephen Boyd 
Cc: Jiri Kosina 
Link: https://lkml.kernel.org/r/0e586dd4-2b27-864e-c252-bc72df52fd01@infradead.org

rcu: Remove nohz_full full-system-idle state machine

2017-06-09T01:52:39+00:00

The NO_HZ_FULL_SYSIDLE full-system-idle capability was added in 2013
by commit 0edd1b1784cb ("nohz_full: Add full-system-idle state machine"),
but has not been used.  This commit therefore removes it.

If it turns out to be needed later, this commit can always be reverted.

Signed-off-by: Paul E. McKenney 
Cc: Frederic Weisbecker 
Cc: Rik van Riel 
Cc: Ingo Molnar 
Acked-by: Linus Torvalds

rcu: Drop RCU_USER_QS in favor of NO_HZ_FULL

2015-07-06T20:52:18+00:00

The RCU_USER_QS Kconfig parameter is now just a synonym for NO_HZ_FULL,
so this commit eliminates RCU_USER_QS, replacing all uses with NO_HZ_FULL.

Reported-by: Frederic Weisbecker 
Signed-off-by: Paul E. McKenney 
Acked-by: Frederic Weisbecker

clockevents: Remove CONFIG_GENERIC_CLOCKEVENTS_BUILD

2015-04-01T12:22:57+00:00

This option was for simpler migration to the clock events code.
Most architectures have been converted and the option has been
disfunctional as a standalone option for quite some time. Remove
it.

Signed-off-by: Thomas Gleixner 
Signed-off-by: Rafael J. Wysocki 
Cc: Peter Zijlstra 
Link: http://lkml.kernel.org/r/5021859.jl9OC1medj@vostro.rjw.lan
Signed-off-by: Ingo Molnar

clocksource: Move cycle_last validation to core code

2014-07-23T22:01:51+00:00

The only user of the cycle_last validation is the x86 TSC. In order to
provide NMI safe accessor functions for clock monotonic and
monotonic_raw we need to do that in the core.

We can't do the TSC specific

    if (now < cycle_last)
       	    now = cycle_last;

for the other wrapping around clocksources, but TSC has
CLOCKSOURCE_MASK(64) which actually does not mask out anything so if
now is less than cycle_last the subtraction will give a negative
result. So we can check for that in clocksource_delta() and return 0
for that case.

Implement and enable it for x86

Signed-off-by: Thomas Gleixner 
Signed-off-by: John Stultz