Re: [PATCH] perf jevents: Fix sys_event_tables to be freed like arch_std_events

[Arnaldo Carvalho de Melo]

Em Tue, Sep 28, 2021 at 02:32:02PM +0100, John Garry escreveu:
> On 28/09/2021 14:22, Arnaldo Carvalho de Melo wrote:
> >   jevents-y      += json.o jsmn.o jevents.o
> > -HOSTCFLAGS_jevents.o   = -I$(srctree)/tools/include
> > +HOSTCFLAGS_jevents.o   = -I$(srctree)/tools/include -Wall -Wextra
> >   pmu-events-y   += pmu-events.o
> >   JDIR           =  pmu-events/arch/$(SRCARCH)
> >   JSON           =  $(shell [ -d $(JDIR) ] &&                            \
> > ⬢[acme@toolbox perf]$
> > 
> > I get this before applying Xu's patch:
> > 
> >    LINK    /tmp/build/perf/libbpf.a
> > pmu-events/jevents.c: In function ‘save_arch_std_events’:
> > pmu-events/jevents.c:473:39: warning: unused parameter ‘data’ [-Wunused-parameter]
> >    473 | static int save_arch_std_events(void *data, struct json_event *je)
> >        |                                 ~~~~~~^~~~
> > At top level:
> > pmu-events/jevents.c:93:13: warning: ‘free_sys_event_tables’ defined but not used [-Wunused-function]
> >     93 | static void free_sys_event_tables(void)
> >        |             ^~~~~~~~~~~~~~~~~~~~~
> > 
> > 
> > -------------------------------------
> > 
> > I'll add this to perf/core, as this isn't a strict fix, so can wait for
> > v5.16.
> 
> Hi Arnaldo,
> 
> OK, would you also consider reusing CFLAGS:
> 
> --- a/tools/perf/pmu-events/Build
> +++ b/tools/perf/pmu-events/Build
> @@ -9,10 +9,12 @@ JSON          =  $(shell [ -d $(JDIR) ] &&
> \
> JDIR_TEST      =  pmu-events/arch/test
> JSON_TEST      =  $(shell [ -d $(JDIR_TEST) ] &&                       \
>                        find $(JDIR_TEST) -name '*.json')
> -
> +HOSTCFLAGS_jevents += $(CFLAGS)

Humm, we have to check if CFLAGS doesn't come with cross-build options,
i.e. IIRC we have to use HOSTCFLAGS instead. Unsure if there is some
*CFLAGS variable that gets the common part, where these -Wall and
-Wextra, -Werror could go.
 
> I tried it, and there are more things to fix for jevents.o. Let me know your
> preference and if any help required to fix any errors up.

I fixed the one I found, see below, I'll test build what I have in
perf/core and push it, then you can continue from there, after checking
this HOSTCFLAGS/CFLAGS issue.

- Arnaldo