On Fri, Jul 26, 2013 at 2:18 PM, Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote: > On Fri, Jul 26, 2013 at 01:55:04PM -0700, Andy Lutomirski wrote: >> On Fri, Jul 26, 2013 at 1:18 PM, Cyrill Gorcunov <gorcunov@xxxxxxxxx> wrote: >> > Andy reported that if file page get reclaimed we loose soft-dirty bit >> > if it was there, so save _PAGE_BIT_SOFT_DIRTY bit when page address >> > get encoded into pte entry. Thus when #pf happens on such non-present >> > pte we can restore it back. >> > >> >> Unless I'm misunderstanding this, it's saving the bit in the >> non-present PTE. This sounds wrong -- what happens if the entire pmd > > It's the same as encoding pgoff in pte entry (pte is not present), > but together with pgoff we save soft-bit status, later on #pf we decode > pgoff and restore softbit back if it was there, pte itself can't disappear > since it holds pgoff information. Isn't that only the case for nonlinear mappings? --Andy -- 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>