Re: [PATCH v3] mm: zswap: multiple zpools support

[Nhat Pham <nphamcs@gmail.com>]

On Fri, Aug 11, 2023 at 4:21 PM Yosry Ahmed <yosryahmed@google.com> wrote:
>
> On Fri, Aug 11, 2023 at 2:19 PM Andrew Morton <akpm@linux-foundation.org> wrote:
> >
> > On Thu, 13 Jul 2023 03:35:25 -0700 Yosry Ahmed <yosryahmed@google.com> wrote:
> >
> > > >
> > > > I'm experimenting with some other zswap changes - if I have
> > > > extra cycles and resources I'll try to apply this patch and see how the
> > > > numbers play out.
> > >
> > > That would be amazing. Looking forward to any numbers you can dig :)
> >
> > So this patch seems stuck.  I can keep it in mm.git until the fog
> > clears, but would prefer not to.  Can we please revisit and decide on a
> > way forward?
>
> Johannes did not like a config option so I proposed it here as a
> constant (like SWAP_CLUSTER_MAX and others we have). This is a value
> that we have been using in our data centers for almost a decade, so it
> has seen a ton of testing. I was hoping Johannes would get time to
> take a look, or Nhat would get time to test it out, but neither of
> these things happen.
Apologies - finally have some time + freed experiment machine cycles
to put in your patch :P And gotta wait a couple of days to obtain sufficient
data.

Result is quite unexciting - no tremendous gains or significant regression
in a bunch of internal metrics I was observing.

Of course, it's just one particular workload that I tested on - there could
be regression/gains in other workloads (or other metrics). But we can
always revisit this when it happens :)

With all that said, the code itself looks solid. And while I'm still not in
love with the change, I don't have any further objections, as of now.
I'll let you (and Johannes) continue from here.

Reviewed-by: Nhat Pham <nphamcs@gmail.com>
Tested-by: Nhat Pham <nphamcs@gmail.com>

>
> I obviously want it to be merged, but hopefully someone will chime in here :)