Re: [PATCH 2/4] mm: introduce mm_forbids_zeropage function

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

 



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 from this list: send the line "unsubscribe kvm" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html




[Index of Archives]     [KVM ARM]     [KVM ia64]     [KVM ppc]     [Virtualization Tools]     [Spice Development]     [Libvirt]     [Libvirt Users]     [Linux USB Devel]     [Linux Audio Users]     [Yosemite Questions]     [Linux Kernel]     [Linux SCSI]     [XFree86]
  Powered by Linux