Messages in this thread | | | Date | Fri, 26 Mar 2004 11:06:19 +0000 | From | Dave Jones <> | Subject | Re: Fw: potential /dev/urandom scalability improvement |
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On Thu, Mar 25, 2004 at 06:00:14PM -0800, Andrew Morton wrote:
> +static inline void prefetch_range(void *addr, size_t len) > +{ > +#ifdef ARCH_HAS_PREFETCH > + char *cp; > + char *end = addr + len; > + > + for (cp = addr; cp < end; cp += PREFETCH_STRIDE) > + prefetch(cp); > +#endif > +} > + > #endif
I think this may be dangerous on some CPUs, if may prefetch past the end of the buffer. Ie, if PREFETCH_STRIDE was 32, and len was 65, we'd end up prefetching 65->97. As well as being wasteful to cachelines, this can crash if theres for eg nothing mapped after the next page boundary.
Dave
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