On Mon, 4 Dec 2006 14:07:47 +0000 [EMAIL PROTECTED] (Mel Gorman) wrote: > o copy_strings() and variants are no longer setting the flag as the pages > are not obviously movable when I took a much closer look. > > o The arch function alloc_zeroed_user_highpage() is now called > __alloc_zeroed_user_highpage and takes flags related to > movability that will be applied. alloc_zeroed_user_highpage() > calls __alloc_zeroed_user_highpage() with no additional flags to > preserve existing behavior of the API for out-of-tree users and > alloc_zeroed_user_highpage_movable() sets the __GFP_MOVABLE flag. > > o new_inode() documents that it uses GFP_HIGH_MOVABLE and callers are expected > to call mapping_set_gfp_mask() if that is not suitable.
umm, OK. Could we please have some sort of statement pinning down the exact semantics of __GFP_MOVABLE, and what its envisaged applications are? My concern is that __GFP_MOVABLE is useful for fragmentation-avoidance, but useless for memory hot-unplug. So that if/when hot-unplug comes along we'll add more gunk which is a somewhat-superset of the GFP_MOVABLE infrastructure, hence we didn't need the GFP_MOVABLE code. Or something. That depends on how we do hot-unplug, if we do it. I continue to suspect that it'll be done via memory zones: effectively by resurrecting GFP_HIGHMEM. In which case there's little overlap with anti-frag. (btw, I have a suspicion that the most important application of memory hot-unplug will be power management: destructively turning off DIMMs). I'd also like to pin down the situation with lumpy-reclaim versus anti-fragmentation. No offence, but I would of course prefer to avoid merging the anti-frag patches simply based on their stupendous size. It seems to me that lumpy-reclaim is suitable for the e1000 problem, but perhaps not for the hugetlbpage problem. Whereas anti-fragmentation adds vastly more code, but can address both problems? Or something. IOW: big-picture where-do-we-go-from-here stuff. - 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/
