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Date: Thu, 1 Feb 2007 14:41:43 +0100 From: Jiri Bohac <jbohac@...e.cz> To: Andi Kleen <ak@...e.de> Cc: jbohac@...e.cz, linux-kernel@...r.kernel.org, Vojtech Pavlik <vojtech@...e.cz>, ssouhlal@...ebsd.org, arjan@...radead.org, tglx@...utronix.de, johnstul@...ibm.com, zippel@...ux-m68k.org, andrea@...e.de Subject: Re: [patch 7/9] Adapt the time initialization code On Thu, Feb 01, 2007 at 12:26:33PM +0100, Andi Kleen wrote: > > > +extern void time_initialize_cpu(void); > > Never put externs into .c files. Multiple occurrences. Ok, will fix it, sorry. > > +void time_initialize_cpu(void *info) > > +{ > > + unsigned long flags; > > + int cpu = smp_processor_id(); > > Are you sure this can never preempt? yes, preemption is explicitly disabled in start_secondary() that calls this function. > > + /* FIXME: what speed does the cpu really start at; I doubt cpu_khz is right at this point ??!!! > > It should be. It comes from measurements. Unless the CPU changes frequency > behind the kernel's back, but there is nothing that can be done then. Well, I'm not sure. I think the global variable cpu_khz is wrong in the first place. This should be per-cpu, because each CPU can have a different frequency, right? And cpu_khz is adjusted in time_cpufreq_notifier() when whichever CPU's frequency changes. To me it seems that it's a leftover from the times when all CPUs in a system ran at the same speed. I think it should be killed. I just did not want to make too many unrelated changes in one patchset. It doesn't matter that much in this case that it probably is wrong (as the comment explains)... -- Jiri Bohac <jbohac@...e.cz> SUSE Labs, SUSE CZ - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@...r.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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