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authorLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 16:31:44 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2019-05-06 16:31:44 -0700
commitdb10ad041b318a07985363e243742a07f4b0f44b (patch)
tree89fe987edb34e0b41885eface16a51df129c17c1
parentba3934de557a2074b89d67e29e5ce119f042d057 (diff)
parent81423c37415fe45057d64196ae0ce8e17a9c7148 (diff)
Merge branch 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip
Pull x86 timer updates from Ingo Molnar: "Two changes: an LTO improvement, plus the new 'nowatchdog' boot option to disable the clocksource watchdog" * 'x86-timers-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip: x86/timer: Don't inline __const_udelay() x86/tsc: Add option to disable tsc clocksource watchdog
-rw-r--r--Documentation/admin-guide/kernel-parameters.txt4
-rw-r--r--arch/x86/kernel/tsc.c5
-rw-r--r--arch/x86/lib/delay.c2
3 files changed, 9 insertions, 2 deletions
diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt
index 420bb17440fd..58e69ec8b7a0 100644
--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -4740,6 +4740,10 @@
[x86] unstable: mark the TSC clocksource as unstable, this
marks the TSC unconditionally unstable at bootup and
avoids any further wobbles once the TSC watchdog notices.
+ [x86] nowatchdog: disable clocksource watchdog. Used
+ in situations with strict latency requirements (where
+ interruptions from clocksource watchdog are not
+ acceptable).
turbografx.map[2|3]= [HW,JOY]
TurboGraFX parallel port interface
diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
index 3fae23834069..aab0c82e0a0d 100644
--- a/arch/x86/kernel/tsc.c
+++ b/arch/x86/kernel/tsc.c
@@ -283,6 +283,7 @@ int __init notsc_setup(char *str)
__setup("notsc", notsc_setup);
static int no_sched_irq_time;
+static int no_tsc_watchdog;
static int __init tsc_setup(char *str)
{
@@ -292,6 +293,8 @@ static int __init tsc_setup(char *str)
no_sched_irq_time = 1;
if (!strcmp(str, "unstable"))
mark_tsc_unstable("boot parameter");
+ if (!strcmp(str, "nowatchdog"))
+ no_tsc_watchdog = 1;
return 1;
}
@@ -1349,7 +1352,7 @@ static int __init init_tsc_clocksource(void)
if (tsc_unstable)
goto unreg;
- if (tsc_clocksource_reliable)
+ if (tsc_clocksource_reliable || no_tsc_watchdog)
clocksource_tsc.flags &= ~CLOCK_SOURCE_MUST_VERIFY;
if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC_S3))
diff --git a/arch/x86/lib/delay.c b/arch/x86/lib/delay.c
index f5b7f1b3b6d7..b7375dc6898f 100644
--- a/arch/x86/lib/delay.c
+++ b/arch/x86/lib/delay.c
@@ -162,7 +162,7 @@ void __delay(unsigned long loops)
}
EXPORT_SYMBOL(__delay);
-void __const_udelay(unsigned long xloops)
+noinline void __const_udelay(unsigned long xloops)
{
unsigned long lpj = this_cpu_read(cpu_info.loops_per_jiffy) ? : loops_per_jiffy;
int d0;