On Wed, 22 Oct 2014 12:22:23 -0700 Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx> wrote: > On Wed, 22 Oct 2014 13:09:28 +0200 Dominik Dingel <dingel@xxxxxxxxxxxxxxxxxx> wrote: > > > Add a new function stub to allow architectures to disable for > > an mm_structthe backing of non-present, anonymous pages with > > read-only empty zero pages. > > > > ... > > > > --- a/include/linux/mm.h > > +++ b/include/linux/mm.h > > @@ -56,6 +56,10 @@ extern int sysctl_legacy_va_layout; > > #define __pa_symbol(x) __pa(RELOC_HIDE((unsigned long)(x), 0)) > > #endif > > > > +#ifndef mm_forbids_zeropage > > +#define mm_forbids_zeropage(X) (0) > > +#endif > > Can we document this please? What it does, why it does it. We should > also specify precisely which arch header file is responsible for > defining mm_forbids_zeropage. > I will add a comment like: /* * To prevent common memory management code establishing * a zero page mapping on a read fault. * This function should be implemented within <asm/pgtable.h>. * s390 does this to prevent multiplexing of hardware bits * related to the physical page in case of virtualization. */ Okay? > -- > 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> > -- 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>