On Thu, Jul 08, 2010 at 02:31:22PM +0300, Kirill A. Shutemov wrote: > On Wed, Jul 07, 2010 at 11:34:18PM +0100, Russell King - ARM Linux wrote: > > On Wed, Jul 07, 2010 at 11:56:01AM +0300, Kirill A. Shutemov wrote: > > > But it seems that the problem is more global. Potentially, any of > > > pmd_none() check may produce false results. I don't see an easy way to fix > > > it. > > > > It isn't. We normally guarantee that we always fill on both L1 entries. > > The only exception is for the mappings specified via create_mapping() > > which is used for the static platform mappings. > > Why do not to change create_mapping() to follow the same rules? > I mean, create sections only if it asked for 2*SECTION_SIZE with > appropriate alignment. It reduces number of section mappings, but, > probably, will be a bit cleaner and less error-prune. > > > > Does Linux VM still expect one PTE table per page? > > > > Yes, and as far as I can see probably always will. Hence why we need > > to put two L1 entries in one page and lie to the kernel about the sizes > > of the hardware entries. > > Another option is leave half of page with PTE table free. Is it very bad > idea? > > How other architectures handle it? Or only on ARM PTL table size is less > than page size? Russell, any comments? I would like to fix it in a right way. -- Kirill A. Shutemov -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxxx For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>