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SubjectRe: [PATCH v7 1/6] x86/tsc: remove tsc_disabled flag
Hi Dou,

Sure, I can remove the warning, but I think we should print something
that is indicating that notsc is not a good parameter anymore: i.e
tsc=unstable is better. Perhaps something like:
"Kernel parameter \'notsc\' is deprecated, please use
\'tsc=unstable\' instead" ?

Pasha

On Thu, Nov 2, 2017 at 9:58 PM, Dou Liyang <douly.fnst@cn.fujitsu.com> wrote:
> Hi Pavel,
>
>
> At 11/03/2017 01:26 AM, Pavel Tatashin wrote:
>>
>> tsc_disabled is set when notsc is passed as kernel parameter. The reason
>> we
>> have notsc is to avoid timing problems on multi-preccors systems. However,
>> we already have a mechanism to detect and resolve these issues by invoking
>> tsc unstable path.
>>
>> Signed-off-by: Pavel Tatashin <pasha.tatashin@oracle.com>
>> ---
>> arch/x86/kernel/tsc.c | 17 +++--------------
>> 1 file changed, 3 insertions(+), 14 deletions(-)
>>
>> diff --git a/arch/x86/kernel/tsc.c b/arch/x86/kernel/tsc.c
>> index 796d96bb0821..1c4502a2b7b2 100644
>> --- a/arch/x86/kernel/tsc.c
>> +++ b/arch/x86/kernel/tsc.c
>> @@ -37,11 +37,6 @@ EXPORT_SYMBOL(tsc_khz);
>> */
>> static int __read_mostly tsc_unstable;
>>
>> -/* native_sched_clock() is called before tsc_init(), so
>> - we must start with the TSC soft disabled to prevent
>> - erroneous rdtsc usage on !boot_cpu_has(X86_FEATURE_TSC) processors */
>> -static int __read_mostly tsc_disabled = -1;
>> -
>> static DEFINE_STATIC_KEY_FALSE(__use_tsc);
>>
>> int tsc_clocksource_reliable;
>> @@ -248,7 +243,7 @@ EXPORT_SYMBOL_GPL(check_tsc_unstable);
>> int __init notsc_setup(char *str)
>> {
>> pr_warn("Kernel compiled with CONFIG_X86_TSC, cannot disable TSC
>> completely\n");
>
>
> IMO, this warning may make users confused, could we remove it from here?
>
> Thanks,
> dou.
>
>

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