Re: [PATCH 2/2] zsmalloc: fine-grained inuse ratio based fullness grouping

Sergey Senozhatsky
2023-02-10T04:24:12Z

On (23/02/07 10:47), Sergey Senozhatsky wrote:
> > > enum fullness_group {
> > > - ZS_EMPTY,
> > > - ZS_ALMOST_EMPTY,
> > > - ZS_ALMOST_FULL,
> > > - ZS_FULL,
> > > + ZS_USAGE_0,
> > > + ZS_USAGE_10,
> > > + ZS_USAGE_20,
> > > + ZS_USAGE_30,
> > > + ZS_USAGE_40,
> > > + ZS_USAGE_50,
> > > + ZS_USAGE_60,
> > > + ZS_USAGE_70,
> > > + ZS_USAGE_80,
> > > + ZS_USAGE_90,
> > > + ZS_USAGE_99,
> > > + ZS_USAGE_100,
> > > NR_ZS_FULLNESS,
> > > };
> > >
> >
> > Is there a reason why this can't be done with something like #define
> > FULLNESS_GROUPS 10? We can make sure during build that (100 %
> > FULLNESS_GROUPS == 0) to make our lives easier. I feel like the code
> > will be much more concise and easier to navigate, instead of multiple
> > enums and static arrays.
>
> I wanted to keep things the way they are to make reviews simpler.
> We probably can do something more "disruptive" in a separate patch.

Forgot to mention, I was also thinking about extending zsmalloc stats
file and providing values for each fullness group per class, as opposed
to current ALMOST_EMPTY and ALMOST_FULL stats, which don't tell much.

I can get rid of static const arrays and pass "begin / end" group IDs to
functions that iterate fullness lists and pick the first head page, but
I think that enum values will stay.