Messages in this thread | | | Subject | Re: [PATCH 1/2] perfcounter: Ignore the nmi call frames in the x86-64 backtraces | From | Peter Zijlstra <> | Date | Mon, 06 Jul 2009 14:17:48 +0200 |
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On Wed, 2009-07-01 at 21:02 +0200, Frederic Weisbecker wrote:
> +int x86_is_stack_id(int id, char *name) > +{ > + return x86_stack_ids[id - 1] == name; > +}
OK, this bit would need a bit of a comment explaining why this works, as I don't think the C language guarantees de-duplication of constant strings.
Therefore the above only works correctly if its passed a pointer from the x86_stack_ids[] array -- as it indeed is, since the string passed is obtained through the below method:
> +static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, > + unsigned *usedp, char **idp) > +{ > unsigned k; > > /* > @@ -61,7 +68,7 @@ static unsigned long *in_exception_stack(unsigned cpu, unsigned long stack, > if (*usedp & (1U << k)) > break; > *usedp |= 1U << k; > - *idp = ids[k]; > + *idp = x86_stack_ids[k]; > return (unsigned long *)end; > } > /*
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