Re: [PATCH v2 1/5] tracing: Add support for creating hist trigger variables from literal

[Kalesh Singh]

On Wed, Oct 20, 2021 at 8:32 AM Steven Rostedt <rostedt@xxxxxxxxxxx> wrote:
>
> On Tue, 19 Oct 2021 18:31:38 -0700
> Kalesh Singh <kaleshsingh@xxxxxxxxxx> wrote:
>
> > @@ -89,6 +91,8 @@ typedef u64 (*hist_field_fn_t) (struct hist_field *field,
> >  #define HIST_FIELD_OPERANDS_MAX      2
> >  #define HIST_FIELDS_MAX              (TRACING_MAP_FIELDS_MAX + TRACING_MAP_VARS_MAX)
> >  #define HIST_ACTIONS_MAX     8
> > +#define HIST_CONST_MAX               4
>
> BTW, why is there a limit to the number of constants?

The motivation was to limit the number of hist_fields that can be
created for constants. These are also indirectly limited by the max
number of subexpressions (3) and the max number of vars/keys that can
be defined, so I don't feel strongly about keeping it.

Thanks,
Kalesh

>
> -- Steve
>
> > +#define HIST_CONST_DIGITS_MAX        21
> >