Re: [PATCH 3/3] mm: optimise pte dirty/accessed bit setting by demand based pte insertion

[Guenter Roeck]

On 09/05/2018 03:18 PM, Nicholas Piggin wrote:
> On Wed, 5 Sep 2018 07:29:51 -0700
> Guenter Roeck <linux@xxxxxxxxxxxx> wrote:
>
> > Hi,
> >
> > On Tue, Aug 28, 2018 at 09:20:34PM +1000, Nicholas Piggin wrote:
> > > Similarly to the previous patch, this tries to optimise dirty/accessed
> > > bits in ptes to avoid access costs of hardware setting them.
> > >    
> >
> > This patch results in silent nios2 boot failures, silent meaning that
> > the boot stalls.
> >
> > ...
> > Unpacking initramfs...
> > Freeing initrd memory: 2168K
> > workingset: timestamp_bits=30 max_order=15 bucket_order=0
> > jffs2: version 2.2. (NAND) Â 2001-2006 Red Hat, Inc.
> > random: fast init done
> > random: crng init done
> >
> > [no further activity until the qemu session is aborted]
> >
> > Reverting the patch fixes the problem. Bisect log is attached.
>
> Thanks for bisecting it, I'll try to reproduce. Just qemu with no
> obscure options? Interesting that it's hit nios2 but apparently not
> other archs (yet).

Nothing special. See https://github.com/groeck/linux-build-test/tree/master/rootfs/nios2/.

Guenter