Hi Andrea, On Fri, Apr 22, 2011 at 1:14 AM, Andrea Arcangeli <aarcange@xxxxxxxxxx> wrote: > On Thu, Apr 21, 2011 at 05:00:57PM +0100, Mel Gorman wrote: >> If you want to create a new patch with either your comment or mine >> (whichever you prefer) I'll add my ack. I'm about to drop offline >> for a few days but if it's still there Tuesday, I'll put together an >> appropriate patch and submit. I'd keep it separate from the other patch >> because it's a performance fix (which I'd like to see in -stable) where >> as this is more of a cleanup IMO. > > I think the older patch should have more priority agreed. This one may > actually waste cpu cycles overall, rather than saving them, it > shouldn't be a common occurrence. > > From a code consistency point of view maybe we should just implement a > pte_alloc macro (to put after pte_alloc_map) and use it in both > places, and hide the glory details of the unlikely in the macro. When > implementing pte_alloc, I suggest also adding unlikely to both, I mean > we added unlikely to the fast path ok, but __pte_alloc is orders of > magnitude less likely to fail than pte_none, and it still runs 1 every > 512 4k page faults, so I think __pte_alloc deserves an unlikely too. > > Minchan, you suggested this cleanup, so I suggest you to send a patch, > but if you're busy we can help. It's no problem to send a patch but I can do it at out-of-office time. Maybe weekend. :) Before doing that, let's clear the point. You mentioned it shouldn't be a common occurrence but you are suggesting we should do for code consistency POV. Am I right? > > Thanks! > Andrea > -- Kind regards, Minchan Kim -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>