On Tue, 2014-07-15 at 12:56 -0700, Andy Lutomirski wrote: > On Tue, Jul 15, 2014 at 12:34 PM, Toshi Kani <toshi.kani@xxxxxx> wrote: > > This patch changes reserve_memtype() to handle the new WT type. > > When (!pat_enabled && new_type), it continues to set either WB > > or UC- to *new_type. When pat_enabled, it can reserve a given > > non-RAM range for WT. At this point, it may not reserve a RAM > > range for WT since reserve_ram_pages_type() uses the page flags > > limited to three memory types, WB, WC and UC. > > FWIW, last time I looked at this, it seemed like all the fancy > reserve_ram_pages stuff was unnecessary: shouldn't the RAM type be > easy to track in the direct map page tables? Are you referring the direct map page tables as the kernel page directory tables (pgd/pud/..)? I think it needs to be able to keep track of the memory type per a physical memory range, not per a translation, in order to prevent aliasing of the memory type. Thanks, -Toshi -- 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>