Re: [PATCH v2] mm: thp: Set the accessed flag for old pages onaccess fault.
From: Will Deacon
Date: Mon Oct 22 2012 - 06:35:25 EST
On Fri, Oct 19, 2012 at 07:49:55PM +0100, Andrew Morton wrote:
> On Fri, 19 Oct 2012 10:10:16 +0100
> Will Deacon <will.deacon@xxxxxxx> wrote:
> > On Thu, Oct 18, 2012 at 11:05:02PM +0100, Andrew Morton wrote:
> > > On Wed, 17 Oct 2012 16:54:02 +0100
> > > Will Deacon <will.deacon@xxxxxxx> wrote:
> > >
> > > > On x86 memory accesses to pages without the ACCESSED flag set result in the
> > > > ACCESSED flag being set automatically. With the ARM architecture a page access
> > > > fault is raised instead (and it will continue to be raised until the ACCESSED
> > > > flag is set for the appropriate PTE/PMD).
> > > >
> > > > For normal memory pages, handle_pte_fault will call pte_mkyoung (effectively
> > > > setting the ACCESSED flag). For transparent huge pages, pmd_mkyoung will only
> > > > be called for a write fault.
> > > >
> > > > This patch ensures that faults on transparent hugepages which do not result
> > > > in a CoW update the access flags for the faulting pmd.
> > >
> > > Confused. Where is the arm implementation of update_mmu_cache_pmd()?
> > Right at the end of this patch, which was posted to the ARM list yesterday:
> > http://lists.infradead.org/pipermail/linux-arm-kernel/2012-October/126387.html
> I received and then merged a patch which won't compile!
Eek, that certainly wasn't intentional and it's compiling fine for me on
-rc1 and -rc2 for both ARM (no THP) and x86 (with and without THP).
Please can you send the build failure?
> Ho hum. I'll drop
> mm-thp-set-the-accessed-flag-for-old-pages-on-access-fault.patch and
> shall assume that you'll sort things out at the appropriate time.
Happy to sort it out once I work out what's going wrong!
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/