On Mon, Jul 15, 2013 at 10:54:38AM -0700, H. Peter Anvin wrote: > On 07/15/2013 10:45 AM, Nathan Zimmer wrote: > > > > I hadn't actually been very happy with having a PG_uninitialized2mib flag. > > It implies if we want to jump to 1Gb pages we would need a second flag, > > PG_uninitialized1gb, for that. I was thinking of changing it to > > PG_uninitialized and setting page->private to the correct order. > > Thoughts? > > > > Seems straightforward. The bigger issue is the amount of overhead we > cause by having to check upstack for the initialization status of the > superpages. > > I'm concerned, obviously, about lingering overhead that is "forever". > That being said, in the absolutely worst case we could have a counter to > the number of uninitialized pages which when it hits zero we do a static > switch and switch out the initialization code (would have to be undone > on memory hotplug, of course.) Is there a fairly cheap way to determine definitively that the struct page is not initialized? I think this patch set can change fairly drastically if we have that. I think I will start working up those changes and code a heavy-handed check until I hear of an alternative way to cheaply check. Thanks, Robin -- 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/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>