On Sat, 2007-02-03 at 09:56 -0800, Christoph Lameter wrote: > On Sat, 3 Feb 2007, Andrew Morton wrote: > > > I wonder if it can be simpler. Make two changes: > > Would be great if this could get simpler. > > > a) If the scanner encounters an mlocked page on the LRU, take it off. > > The current patch takes them off when mlock is set (which may not work > since the page may be off the LRU) and then has the scanner taking them > off. We could just remove the early one but what would this bring us?
it's simpler. You only move them off when you encounter them during a scan. No walking early etc etc. Only do work when there is an actual situation where you do scan. > > > b) munlock() adds all affected pages to the LRU. > > Hmmm... You mean without checking all the vmas of a page for VM_LOCKED? So > they > are going to be removed again on the next pass? Ok. I see that makes it > simpler but it requires another reclaim scan. Well.. That's the point! Only IF there is a reclaim scan do you move them out again. The fact that these pages are on the list isn't a problem. The fact that you keep encountering them over and over again during *scanning* is. So Andrews suggestion makes them go away in the situations that actually matter > The page flag allows a clean state transition of a page and accurate > keeping of statistics for MLOCKed pages. There were objections against the > fuzzy counting in the earlier incarnation and it was proposed that a page > flag be introduced. Without the flag we cannot know that the page is > already mapped by a VM_LOCKED vma without scanning over all vmas > referencing the page. who cares though.. just do it lazy. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to [EMAIL PROTECTED] More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
