From: Pavel Tatashin <pasha.tatashin@oracle.com>
To: steven.sistare@oracle.com, daniel.m.jordan@oracle.com,
linux@armlinux.org.uk, schwidefsky@de.ibm.com,
heiko.carstens@de.ibm.com, john.stultz@linaro.org,
sboyd@codeaurora.org, x86@kernel.org,
linux-kernel@vger.kernel.org, mingo@redhat.com,
tglx@linutronix.de, hpa@zytor.com, douly.fnst@cn.fujitsu.com,
peterz@infradead.org, prarit@redhat.com, feng.tang@intel.com,
pmladek@suse.com, gnomes@lxorguk.ukuu.org.uk,
linux-s390@vger.kernel.org
Subject: [PATCH v12 10/11] sched: early boot clock
Date: Thu, 21 Jun 2018 17:25:17 -0400 [thread overview]
Message-ID: <20180621212518.19914-11-pasha.tatashin@oracle.com> (raw)
In-Reply-To: <20180621212518.19914-1-pasha.tatashin@oracle.com>
Allow sched_clock() to be used before schec_clock_init() and
sched_clock_init_late() are called. This provides us with a way to get
early boot timestamps on machines with unstable clocks.
Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
---
kernel/sched/clock.c | 10 ++++++++--
1 file changed, 8 insertions(+), 2 deletions(-)
diff --git a/kernel/sched/clock.c b/kernel/sched/clock.c
index 10c83e73837a..f034392b0f6c 100644
--- a/kernel/sched/clock.c
+++ b/kernel/sched/clock.c
@@ -205,6 +205,11 @@ void clear_sched_clock_stable(void)
*/
static int __init sched_clock_init_late(void)
{
+ /* Transition to unstable clock from early clock */
+ local_irq_disable();
+ __gtod_offset = sched_clock() + __sched_clock_offset - ktime_get_ns();
+ local_irq_enable();
+
sched_clock_running = 2;
/*
* Ensure that it is impossible to not do a static_key update.
@@ -350,8 +355,9 @@ u64 sched_clock_cpu(int cpu)
if (sched_clock_stable())
return sched_clock() + __sched_clock_offset;
- if (unlikely(!sched_clock_running))
- return 0ull;
+ /* Use early clock until sched_clock_init_late() */
+ if (unlikely(sched_clock_running < 2))
+ return sched_clock() + __sched_clock_offset;
preempt_disable_notrace();
scd = cpu_sdc(cpu);
--
2.17.1
next prev parent reply other threads:[~2018-06-21 21:26 UTC|newest]
Thread overview: 69+ messages / expand[flat|nested] mbox.gz Atom feed top
2018-06-21 21:25 [PATCH v12 00/11] Early boot time stamps for x86 Pavel Tatashin
2018-06-21 21:25 ` [PATCH v12 01/11] x86: text_poke() may access uninitialized struct pages Pavel Tatashin
2018-06-21 21:37 ` Randy Dunlap
2018-06-25 8:14 ` Peter Zijlstra
2018-06-25 8:39 ` Thomas Gleixner
2018-06-25 9:09 ` Peter Zijlstra
2018-06-25 9:18 ` Thomas Gleixner
2018-06-25 9:22 ` Peter Zijlstra
2018-06-25 12:32 ` Pavel Tatashin
2018-06-25 13:48 ` Peter Zijlstra
2018-06-25 14:06 ` Pavel Tatashin
2018-06-21 21:25 ` [PATCH v12 02/11] x86: initialize static branching early Pavel Tatashin
2018-06-23 9:16 ` Borislav Petkov
2018-06-23 13:11 ` Pavel Tatashin
2018-06-21 21:25 ` [PATCH v12 03/11] x86/tsc: redefine notsc to behave as tsc=unstable Pavel Tatashin
2018-06-23 13:32 ` Thomas Gleixner
2018-06-21 21:25 ` [PATCH v12 04/11] kvm/x86: remove kvm memblock dependency Pavel Tatashin
2018-06-23 13:36 ` Thomas Gleixner
2018-07-05 16:12 ` Paolo Bonzini
2018-07-06 9:24 ` Thomas Gleixner
2018-07-06 9:36 ` Paolo Bonzini
2018-07-06 9:45 ` Thomas Gleixner
2018-07-06 10:08 ` Paolo Bonzini
2018-07-06 10:44 ` Thomas Gleixner
2018-07-06 10:50 ` Thomas Gleixner
2018-07-06 15:03 ` Pavel Tatashin
2018-07-06 15:09 ` Paolo Bonzini
2018-06-21 21:25 ` [PATCH v12 05/11] s390/time: add read_persistent_wall_and_boot_offset() Pavel Tatashin
2018-06-25 7:07 ` Martin Schwidefsky
2018-06-25 12:45 ` Pavel Tatashin
2018-06-21 21:25 ` [PATCH v12 06/11] time: replace read_boot_clock64() with read_persistent_wall_and_boot_offset() Pavel Tatashin
2018-06-23 13:49 ` Thomas Gleixner
2018-06-21 21:25 ` [PATCH v12 07/11] s390/time: remove read_boot_clock64() Pavel Tatashin
2018-06-21 21:25 ` [PATCH v12 08/11] ARM/time: " Pavel Tatashin
2018-06-23 13:52 ` Thomas Gleixner
2018-06-21 21:25 ` [PATCH v12 09/11] x86/tsc: prepare for early sched_clock Pavel Tatashin
2018-06-23 16:50 ` Thomas Gleixner
2018-06-23 18:49 ` Pavel Tatashin
2018-06-23 20:11 ` Thomas Gleixner
2018-06-23 21:29 ` Pavel Tatashin
2018-06-23 23:38 ` Thomas Gleixner
2018-06-24 2:43 ` Pavel Tatashin
2018-06-24 7:30 ` Thomas Gleixner
2018-06-26 15:42 ` Thomas Gleixner
2018-06-26 18:42 ` Pavel Tatashin
2018-06-26 19:47 ` Pavel Tatashin
2018-06-28 7:31 ` Thomas Gleixner
2018-06-28 10:43 ` Thomas Gleixner
2018-06-28 11:46 ` Peter Zijlstra
2018-06-28 12:27 ` Thomas Gleixner
2018-06-28 19:42 ` Pavel Tatashin
2018-06-29 7:30 ` Thomas Gleixner
2018-06-29 8:57 ` Pavel Tatashin
2018-07-03 20:59 ` Thomas Gleixner
2018-07-02 17:18 ` Konrad Rzeszutek Wilk
2018-06-29 14:30 ` Andy Shevchenko
2018-06-29 17:50 ` Andy Shevchenko
2018-07-09 23:16 ` Boris Ostrovsky
2018-06-21 21:25 ` Pavel Tatashin [this message]
2018-06-25 8:55 ` [PATCH v12 10/11] sched: early boot clock Peter Zijlstra
2018-06-25 12:44 ` Pavel Tatashin
2018-06-25 19:23 ` Pavel Tatashin
2018-06-26 9:00 ` Peter Zijlstra
2018-06-26 11:27 ` Pavel Tatashin
2018-06-26 11:51 ` Pavel Tatashin
2018-06-26 15:07 ` Peter Zijlstra
2018-06-21 21:25 ` [PATCH v12 11/11] x86/tsc: use tsc early Pavel Tatashin
2018-06-23 16:56 ` Thomas Gleixner
2018-06-23 21:38 ` Pavel Tatashin
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