On Thu, Jul 11, 2013 at 09:03:51PM -0500, Robin Holt wrote: > We have been working on this since we returned from shutdown and have > something to discuss now. We restricted ourselves to 2MiB initialization > to keep the patch set a little smaller and more clear. > > First, I think I want to propose getting rid of the page flag. If I knew > of a concrete way to determine that the page has not been initialized, > this patch series would look different. If there is no definitive > way to determine that the struct page has been initialized aside from > checking the entire page struct is zero, then I think I would suggest > we change the page flag to indicate the page has been initialized. Ingo or HPA, Did I implement this wrong or is there a way to get rid of the page flag which is not going to impact normal operation? I don't want to put too much more effort into this until I know we are stuck going this direction. Currently, the expand() function has a relatively expensive checked against the 2MiB aligned pfn's struct page. I do not know of a way to eliminate that check against the other page as the first reference we see for a page is in the middle of that 2MiB aligned range. To identify this as an area of concern, we had booted with a simulator, setting watch points on the struct page array region once the Uninitialized flag was set and maintaining that until it was cleared. 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>