Re: [PATCH v2 2/3] mm: page_counter: rearrange struct page_counter fields

[Shakeel Butt]

On Wed, Aug 24, 2022 at 10:21 PM Andrew Morton
<akpm@xxxxxxxxxxxxxxxxxxxx> wrote:
>
> On Wed, 24 Aug 2022 21:41:42 -0700 Shakeel Butt <shakeelb@xxxxxxxxxx> wrote:
>
> > > Did you evaluate the effects of using a per-cpu counter of some form?
> >
> > Do you mean per-cpu counter for usage or something else?
>
> percpu_counter, perhaps.  Or some hand-rolled thing if that's more suitable.
>
> > The usage
> > needs to be compared against the limits and accumulating per-cpu is
> > costly particularly on larger machines,
>
> Well, there are tricks one can play.  For example, only run
> __percpu_counter_sum() when `usage' is close to its limit.
>
> I'd suggest flinging together a prototype which simply uses
> percpu_counter_read() all the time.  If the performance testing results
> are sufficiently promising, then look into the accuracy issues.
>

Thanks, I will take a stab at that in a week or so.