Messages in this thread | | | From | Linus Torvalds <> | Date | Thu, 5 Jul 2012 14:47:52 -0700 | Subject | Re: [PATCH 01/10] random: make 'add_interrupt_randomness()' do something sane |
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On Thu, Jul 5, 2012 at 2:39 PM, Matt Mackall <mpm@selenic.com> wrote: > > From my read, this code path gets called on timer interrupts too.
That's hopefully never true for any normal cases (timers are *very* special - they tend to go through their own architecture-specific stuff). On modern PC's, for example, the timers happen through the local apic timers directly.
In fact, with SMP, it's a really bad idea to use a normal irq for timer interrupts, since you really really want per-CPU-core timers.
But yes, we should probably make sure that *if* the architecture uses regular interrupts for timers we don't count them. The problematic embedded platforms are often pretty crap hardware: even when they are SMP, they might use an external timer irq (and then we broadcast the thing). I think we have the IRQF_TIMER flag for that, so we could add a check for that.
Linus
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