On Thu, 29 Dec 2011, Andrew Morton wrote: > > This is not all some handwavy theoretical thing either. If we've gone > and introduced serious latency issues, people *will* hit them and treat > it as a regression. Sure, though the worst I've seen so far (probably haven't been trying hard enough yet, I need to go for THPs) is 39 pages freed in one call. Regression? Well, any bad latency would already have been there on the gathering side. > > Now, a way out here is to remove lumpy reclaim (please). And make the > problem not come back by promising to never call putback_lru_pages(lots > of pages) (how do we do this?). We can very easily put a counter in it, doing a spin_unlock_irq every time we hit the max. Nothing prevents that, it's just an excrescence I'd have preferred to omit and have not today implemented. > > So I think the best way ahead here is to distribute this patch in the > same release in which we remove lumpy reclaim (pokes Mel). I'm sure there are better reasons for removing lumpy than that I posted a patch which happened to remove some limitation. No need to poke Mel on my behalf! Hugh -- 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=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>