On 2014/5/20 6:35, Luck, Tony wrote:
>> Another problem, maybe we should use get_jiffies_64() instead of jiffies
>> directly here OR we'll meet wraparound problems on 32bit system. But a
>> same problem is that the jiffies_lock is not safe in NMI context...
>
> To quote Winnie the Pooh - "Bother".
> Another problem, maybe we should use get_jiffies_64() instead of jiffies
> directly here OR we'll meet wraparound problems on 32bit system. But a
> same problem is that the jiffies_lock is not safe in NMI context...
To quote Winnie the Pooh - "Bother".
Can someone think of a clever way to get a
On 2014/4/9 1:32, Tony Luck wrote:
> The "uptime" tracer added in:
> commit 8aacf017b065a805d27467843490c976835eb4a5
> tracing: Add "uptime" trace clock that uses jiffies
> has wraparound problems when the system has been up more
> than 1 hour 11 minutes and 34 seconds. It converts jiffies
On Fri, 16 May 2014 17:17:46 +
"Luck, Tony" wrote:
> Is this function safe to call in every context (including NMI & machine
> check)?
> [it uses read_seqcount_begin/read_seqcount_retry ... which I *think* is
> safe ... but this stuff is tricky, so I'd like some reassurance].
No, read_seqco
> How about get uptime by get_monotonic_boottime() directly, which's
> the same as /proc/uptime.
I don't know. get_monotonic_boottime() had existed for many releases
at the point the uptime trace clock was added - so it was an available
choice. Maybe not noticed by
Is this function safe to call
2014-04-09 1:32 GMT+08:00 Tony Luck :
> The "uptime" tracer added in:
> commit 8aacf017b065a805d27467843490c976835eb4a5
> tracing: Add "uptime" trace clock that uses jiffies
> has wraparound problems when the system has been up more
> than 1 hour 11 minutes and 34 seconds. It converts jiffi
The "uptime" tracer added in:
commit 8aacf017b065a805d27467843490c976835eb4a5
tracing: Add "uptime" trace clock that uses jiffies
has wraparound problems when the system has been up more
than 1 hour 11 minutes and 34 seconds. It converts jiffies
to nanoseconds using:
(u64)jiffies_to
+ if (jl < 4*HZ) {
That was lazy ... should be something like:
+ if (jl < (u64)UINT_MAX * HZ / NSEC_PER_SEC)
-Tony
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The "uptime" tracer added in:
commit 8aacf017b065a805d27467843490c976835eb4a5
tracing: Add "uptime" trace clock that uses jiffies
has wraparound problems when the system has been up more
than 1 hour 11 minutes and 34 seconds. It converts jiffies
to nanoseconds using:
(u64)jiffies_to
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