From: Nick Piggin <npiggin@xxxxxxx> Date: Fri, 28 Mar 2008 04:31:50 +0100 > Basically, the pfn-based mapping insertion (vm_insert_pfn, remap_pfn_range) > calls pte_mkspecial. And that tells fast_gup "hands off". I don't think it's wise to allocate a "soft PTE bit" for this on every platform, especially for such a limited use case. Is it feasible to test the page instead? Or are we talking about cases where there may not be a backing page? If the issue is to discern things like I/O mappings and such vs. real pages, there are ways a platform can handle that without a special bit. That would leave us with real memory that does not have backing page structs, and we have a way to test that too. The special PTE bit seems superfluous to me. -- To unsubscribe from this list: send the line "unsubscribe linux-arch" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
