Re: [PATCH v2 5/6] mm: flush memcg percpu stats and events before releasing

From: Roman Gushchin
Date: Wed Mar 13 2019 - 14:25:09 EST


On Wed, Mar 13, 2019 at 12:00:17PM -0400, Johannes Weiner wrote:
> On Tue, Mar 12, 2019 at 03:34:02PM -0700, Roman Gushchin wrote:
> > Flush percpu stats and events data to corresponding before releasing
> > percpu memory.
> >
> > Although per-cpu stats are never exactly precise, dropping them on
> > floor regularly may lead to an accumulation of an error. So, it's
> > safer to flush them before releasing.
> >
> > To minimize the number of atomic updates, let's sum all stats/events
> > on all cpus locally, and then make a single update per entry.
> >
> > Signed-off-by: Roman Gushchin <guro@xxxxxx>
>
> Acked-by: Johannes Weiner <hannes@xxxxxxxxxxx>
>
> Do you mind merging 6/6 into this one? That would make it easier to
> verify that the code added in this patch and the code removed in 6/6
> are indeed functionally equivalent.
>

I did try, but the result is the mess of added and removed lines,
which are *almost* the same, but are slightly different (e.g. tabs).
So it's much easier to review it as two separate patches.

Thanks!