Re: [PATCH 2/6] mm: vmstat: move slab statistics from zone to node counters

Johannes Weiner
2017-06-05T18:35:11Z

On Thu, Jun 01, 2017 at 08:07:28PM +1000, Michael Ellerman wrote:
> Yury Norov <ynorov@caviumnetworks.com> writes:
>
> > On Wed, May 31, 2017 at 01:39:00PM +0200, Heiko Carstens wrote:
> >> On Wed, May 31, 2017 at 11:12:56AM +0200, Heiko Carstens wrote:
> >> > On Tue, May 30, 2017 at 02:17:20PM -0400, Johannes Weiner wrote:
> >> > > To re-implement slab cache vs. page cache balancing, we'll need the
> >> > > slab counters at the lruvec level, which, ever since lru reclaim was
> >> > > moved from the zone to the node, is the intersection of the node, not
> >> > > the zone, and the memcg.
> >> > >
> >> > > We could retain the per-zone counters for when the page allocator
> >> > > dumps its memory information on failures, and have counters on both
> >> > > levels - which on all but NUMA node 0 is usually redundant. But let's
> >> > > keep it simple for now and just move them. If anybody complains we can
> >> > > restore the per-zone counters.
> >> > >
> >> > > Signed-off-by: Johannes Weiner <hannes@cmpxchg.org>
> >> >
> >> > This patch causes an early boot crash on s390 (linux-next as of today).
> >> > CONFIG_NUMA on/off doesn't make any difference. I haven't looked any
> >> > further into this yet, maybe you have an idea?
> >
> > The same on arm64.
>
> And powerpc.

It looks like we need the following on top. I can't reproduce the
crash, but it's verifiable with WARN_ONs in the vmstat functions that
the nodestat array isn't properly initialized when slab bootstraps:

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