On Mon, 2012-03-19 at 14:04 +0100, Andrea Arcangeli wrote: > About the cost of the actual pagetable scanner, you're not being > rational about it. You should measure it for once, take khugepaged > make it scan 1G of memory per millisecond and measure the cost. Death by a thousand cuts.. > You keep complaining about the unaccountability of the pagetable > scanners in terms of process load, and that's a red herring as far as > I can tell. The irqs and ksoftirqd load in a busy server, is likely > much higher than whatever happens at the pagetable scanner level (sure > thing for khugepaged and by an huge order of magnitude so). Who says I agree with ksoftirqd? I would love to get rid of all things softirq. And I also think workqueues are over-/ab-used. > I don't > think this is a relevant concern anyway because the pagetable scanners > go over all memory in a equal amount so the cost would be evenly > distributed for all processes over time (the same cannot be said about > the irqs and ksoftrqid that will benefit only a few processes doing > I/O). So what about the case where all I do is compile kernels and we already have near perfect locality because everything is short running? You're still scanning that memory, and I get no benefit. -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/ Don't email: <a href