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

From: John Garry
Date: Tue Sep 28 2021 - 16:27:24 EST

On 28/09/2021 18:56, Arnaldo Carvalho de Melo wrote:
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
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.

not sure. As I see, the bulk of flags we have in CFLAGS comes from EXTRA_WARNINGS in scripts/Makefile.include; but CFLAGS seems to also include EXTRA_CLAGS, which are for cross-builds (see perf/Makefile.config)

So maybe we just need to use EXTRA_WARNINGS for HOST_CFLAGS

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

- Arnaldo

From 0e46c8307574a8e2dac8d7ba97e0f6f4bbee67a5 Mon Sep 17 00:00:00 2001
From: Arnaldo Carvalho de Melo<acme@xxxxxxxxxx>
Date: Tue, 28 Sep 2021 14:15:01 -0300
Subject: [PATCH 1/1] perf jevents: Add __maybe_unused attribute to unused
function arg

The tools/perf/pmu-events/jevents.c file isn't being compiled with
-Werror and -Wextra, which will be the case soon, so before we turn
those compiler flags on, fix what it would flag.

Cc: Alexander Shishkin<alexander.shishkin@xxxxxxxxxxxxxxx>
Cc: Ingo Molnar<mingo@xxxxxxxxxx>
Cc: Jiri Olsa<jolsa@xxxxxxxxxx>
Cc: Like Xu<like.xu.linux@xxxxxxxxx>
Cc: Mark Rutland<mark.rutland@xxxxxxx>
Cc: Namhyung Kim<namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra<peterz@xxxxxxxxxxxxx>
Signed-off-by: Arnaldo Carvalho de Melo<acme@xxxxxxxxxx>
To: John Garry<john.garry@xxxxxxxxxx>


Reviewed-by: John Garry <john.garry@xxxxxxxxxx>

tools/perf/pmu-events/jevents.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/tools/perf/pmu-events/jevents.c b/tools/perf/pmu-events/jevents.c
index 6731b3cf0c2fc9b7..323e1dfe2436c049 100644
--- a/tools/perf/pmu-events/jevents.c
+++ b/tools/perf/pmu-events/jevents.c
@@ -45,6 +45,7 @@
#include <sys/resource.h> /* getrlimit */
#include <ftw.h>
#include <sys/stat.h>
+#include <linux/compiler.h>
#include <linux/list.h>
#include "jsmn.h"
#include "json.h"
@@ -470,7 +471,7 @@ static void free_arch_std_events(void)
-static int save_arch_std_events(void *data, struct json_event *je)
+static int save_arch_std_events(void *data __maybe_unused, struct json_event *je)
struct event_struct *es;