提交 · 6a55617ed5d1aa62b850de2cf66f5ede2eef4825 · OpenHarmony / kernel_linux

31 7月, 2008 1 次提交

sched clock: revert various sched_clock() changes · e4e4e534

由 Ingo Molnar 提交于 4月 14, 2008

Found an interactivity problem on a quad core test-system - simple
CPU loops would occasionally delay the system un an unacceptable way.

After much debugging with Peter Zijlstra it turned out that the problem
is caused by the string of sched_clock() changes - they caused the CPU
clock to jump backwards a bit - which confuses the scheduler arithmetics.

(which is unsigned for performance reasons)

So revert:

 # c300ba25: sched_clock: and multiplier for TSC to gtod drift
 # c0c87734: sched_clock: only update deltas with local reads.
 # af52a90a: sched_clock: stop maximum check on NO HZ
 # f7cce27f: sched_clock: widen the max and min time

This solves the interactivity problems.
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Acked-by: NPeter Zijlstra <a.p.zijlstra@chello.nl>
Acked-by: NMike Galbraith <efault@gmx.de>

e4e4e534

26 7月, 2008 1 次提交

cpumask: change cpumask_of_cpu_ptr to use new cpumask_of_cpu · 0bc3cc03

由 Mike Travis 提交于 7月 24, 2008

  * Replace previous instances of the cpumask_of_cpu_ptr* macros
    with a the new (lvalue capable) generic cpumask_of_cpu().
Signed-off-by: NMike Travis <travis@sgi.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Jack Steiner <steiner@sgi.com>
Cc: Rusty Russell <rusty@rustcorp.com.au>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

0bc3cc03

22 7月, 2008 1 次提交

sysdev: Pass the attribute to the low level sysdev show/store function · 4a0b2b4d

由 Andi Kleen 提交于 7月 01, 2008

This allow to dynamically generate attributes and share show/store
functions between attributes. Right now most attributes are generated
by special macros and lots of duplicated code. With the attribute
passed it's instead possible to attach some data to the attribute
and then use that in shared low level functions to do different things.

I need this for the dynamically generated bank attributes in the x86
machine check code, but it'll allow some further cleanups.

I converted all users in tree to the new show/store prototype. It's a single
huge patch to avoid unbisectable sections.

Runtime tested: x86-32, x86-64
Compiled only: ia64, powerpc
Not compile tested/only grep converted: sh, arm, avr32
Signed-off-by: NAndi Kleen <ak@linux.intel.com>
Signed-off-by: NGreg Kroah-Hartman <gregkh@suse.de>

4a0b2b4d

19 7月, 2008 2 次提交

cpumask: Optimize cpumask_of_cpu in kernel/time/tick-common.c · c18a41fb

由 Mike Travis 提交于 7月 15, 2008

  * Optimize various places where a pointer to the cpumask_of_cpu value
    will result in reducing stack pressure.
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

c18a41fb

nohz: prevent tick stop outside of the idle loop · b8f8c3cf

由 Thomas Gleixner 提交于 7月 18, 2008

Jack Ren and Eric Miao tracked down the following long standing
problem in the NOHZ code:

	scheduler switch to idle task
	enable interrupts

Window starts here

	----> interrupt happens (does not set NEED_RESCHED)
	      	irq_exit() stops the tick

	----> interrupt happens (does set NEED_RESCHED)

	return from schedule()
	
	cpu_idle(): preempt_disable();

Window ends here

The interrupts can happen at any point inside the race window. The
first interrupt stops the tick, the second one causes the scheduler to
rerun and switch away from idle again and we end up with the tick
disabled.

The fact that it needs two interrupts where the first one does not set
NEED_RESCHED and the second one does made the bug obscure and extremly
hard to reproduce and analyse. Kudos to Jack and Eric.

Solution: Limit the NOHZ functionality to the idle loop to make sure
that we can not run into such a situation ever again.

cpu_idle()
{
	preempt_disable();

	while(1) {
		 tick_nohz_stop_sched_tick(1); <- tell NOHZ code that we
		 			          are in the idle loop

		 while (!need_resched())
		       halt();

		 tick_nohz_restart_sched_tick(); <- disables NOHZ mode
		 preempt_enable_no_resched();
		 schedule();
		 preempt_disable();
	}
}

In hindsight we should have done this forever, but ... 

/me grabs a large brown paperbag.

Debugged-by: Jack Ren <jack.ren@marvell.com>, 
Debugged-by: Neric miao <eric.y.miao@gmail.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

b8f8c3cf

11 7月, 2008 2 次提交

sched_clock: stop maximum check on NO HZ · af52a90a

由 Steven Rostedt 提交于 7月 07, 2008

Working with ftrace I would get large jumps of 11 millisecs or more with
the clock tracer. This killed the latencing timings of ftrace and also
caused the irqoff self tests to fail.

What was happening is with NO_HZ the idle would stop the jiffy counter and
before the jiffy counter was updated the sched_clock would have a bad
delta jiffies to compare with the gtod with the maximum.

The jiffies would stop and the last sched_tick would record the last gtod.
On wakeup, the sched clock update would compare the gtod + delta jiffies
(which would be zero) and compare it to the TSC. The TSC would have
correctly (with a stable TSC) moved forward several jiffies. But because the
jiffies has not been updated yet the clock would be prevented from moving
forward because it would appear that the TSC jumped too far ahead.

The clock would then virtually stop, until the jiffies are updated. Then
the next sched clock update would see that the clock was very much behind
since the delta jiffies is now correct. This would then jump the clock
forward by several jiffies.

This caused ftrace to report several milliseconds of interrupts off
latency at every resume from NO_HZ idle.

This patch adds hooks into the nohz code to disable the checking of the
maximum clock update when nohz is in effect. It resumes the max check
when nohz has updated the jiffies again.
Signed-off-by: NSteven Rostedt <srostedt@redhat.com>
Cc: Steven Rostedt <srostedt@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

af52a90a

nohz: don't stop idle tick if softirqs are pending. · 857f3fd7

由 Heiko Carstens 提交于 7月 11, 2008

In case a cpu goes idle but softirqs are pending only an error message is
printed to the console. It may take a very long time until the pending
softirqs will finally be executed. Worst case would be a hanging system.

With this patch the timer tick just continues and the softirqs will be
executed after the next interrupt. Still a delay but better than a
hanging system.

Currently we have at least two device drivers on s390 which under certain
circumstances schedule a tasklet from process context. This is a reason
why we can end up with pending softirqs when going idle. Fixing these
drivers seems to be non-trivial.
However there is no question that the drivers should be fixed.
This patch shouldn't be considered as a bug fix. It just is intended to
keep a system running even if device drivers are buggy.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Jan Glauber <jan.glauber@de.ibm.com>
Cc: Stefan Weinhuber <wein@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

857f3fd7

08 7月, 2008 1 次提交

x86, clockevents: add C1E aware idle function · aa276e1c

由 Thomas Gleixner 提交于 6月 09, 2008

C1E on AMD machines is like C3 but without control from the OS. Up to
now we disabled the local apic timer for those machines as it stops
when the CPU goes into C1E. This excludes those machines from high
resolution timers / dynamic ticks, which hurts especially X2 based
laptops.

The current boot time C1E detection has another, more serious flaw
as well: some BIOSes do not enable C1E until the ACPI processor module
is loaded. This causes systems to stop working after that point.

To work nicely with C1E enabled machines we use a separate idle
function, which checks on idle entry whether C1E was enabled in the
Interrupt Pending Message MSR. This allows us to do timer broadcasting
for C1E and covers the late enablement of C1E as well.
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

aa276e1c

26 6月, 2008 1 次提交

smp_call_function: get rid of the unused nonatomic/retry argument · 8691e5a8

由 Jens Axboe 提交于 6月 06, 2008

It's never used and the comments refer to nonatomic and retry
interchangably. So get rid of it.
Acked-by: NJeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Signed-off-by: NJens Axboe <jens.axboe@oracle.com>

8691e5a8

30 5月, 2008 2 次提交

I
nohz: reduce jiffies polling overhead · 7a14ce1d
由 Ingo Molnar 提交于 5月 12, 2008
```
Signed-off-by: NIngo Molnar <mingo@elte.hu>
```
7a14ce1d

softlockup: fix false positives on nohz if CPU is 100% idle for more than 60 seconds · 02ff3755

由 Ingo Molnar 提交于 5月 12, 2008

Fix (probably theoretical only) rq->clock update bug:
in tick_nohz_update_jiffies() [which is called on all irq
entry on all cpus where the irq entry hits an idle cpu] we
call touch_softlockup_watchdog() before we update jiffies.
That works fine most of the time when idle timeouts are within
60 seconds. But when an idle timeout is beyond 60 seconds,
jiffies is updated with a jump of more than 60 seconds,
which causes a jump in cpu-clock of more than 60 seconds,
triggering a false positive.
Reported-by: NDavid Miller <davem@davemloft.net>
Signed-off-by: NIngo Molnar <mingo@elte.hu>

02ff3755

24 5月, 2008 1 次提交

clocksource/events: use performance variant for_each_cpu_mask_nr · cad0e458

由 Mike Travis 提交于 5月 12, 2008

Change references from for_each_cpu_mask to for_each_cpu_mask_nr
where appropriate
Reviewed-by: NPaul Jackson <pj@sgi.com>
Reviewed-by: NChristoph Lameter <clameter@sgi.com>
Signed-off-by: NMike Travis <travis@sgi.com>
Signed-off-by: NIngo Molnar <mingo@elte.hu>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

cad0e458

04 5月, 2008 2 次提交

clocksource: allow read access to available/current_clocksource · 4f95f81a

由 Heiko Carstens 提交于 5月 03, 2008

There is no harm, when users can read the info and we ask often enough
during debugging for this kind of information.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: John Stultz <johnstul@us.ibm.com>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

4f95f81a

clocksource: Fix permissions for available_clocksource · 4359a023

由 Heiko Carstens 提交于 5月 02, 2008

File permissions for
/sys/devices/system/clocksource/clocksource0/available_clocksource
are 600 which allows write access. But this is in fact a read only
file. So change permissions to 400.
Signed-off-by: NHeiko Carstens <heiko.carstens@de.ibm.com>
Cc: John Stultz <johnstul@us.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: NThomas Gleixner <tglx@linutronix.de>

4359a023

01 5月, 2008 10 次提交

ntp: handle leap second via timer · 7dffa3c6