On Wed, Oct 14, 2020 at 08:21:57PM -0700, Ankur Arora wrote: > Also, if we did extend clear_page() to take the page-size as parameter > we still might not have enough information (ex. a 4K or a 2MB page that > clear_page() sees could be part of a GUP of a much larger extent) to > decide whether to go uncached or not. clear_page* assumes 4K. All of the lowlevel asm variants do. So adding the size there won't bring you a whole lot. So you'd need to devise this whole thing differently. Perhaps have a clear_pages() helper which decides based on size what to do: uncached clearing or the clear_page() as is now in a loop. Looking at the callsites would give you a better idea I'd say. Thx. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette