Re: [PATCH] Revert "perf cs-etm: Move definition of 'traceid_list' global variable from header file"

[Leo Yan <leo.yan@linaro.org>]

On Fri, Nov 20, 2020 at 10:54:22AM +0100, Andrey Zhizhikin wrote:
> On Fri, Nov 20, 2020 at 8:39 AM Salvatore Bonaccorso <carnil@debian.org> wrote:
> >
> > This reverts commit 168200b6d6ea0cb5765943ec5da5b8149701f36a upstream.
> > (but only from 4.19.y)
> 
> This revert would fail the build of 4.19.y with gcc10, I believe the
> original commit was introduced to address exactly this case. If this
> is intended behavior that 4.19.y is not compiled with newer gcc
> versions - then this revert is OK.

The original commit has a dependency for commit 95c6fe970a01 ("perf
cs-etm: Change tuple from traceID-CPU# to traceID-metadata").  If the
commit 95c6fe970a01 is not backported on v4.19.y, then I think reverting
in this patch is the right way to do.

Thanks,
Leo

> > The original commit introduces a build failure as seen on Debian buster
> > when compiled with gcc (Debian 8.3.0-6) 8.3.0:
> >
> >   $ LC_ALL=C.UTF-8 ARCH=x86 make perf
> >   [...]
> >   Warning: Kernel ABI header at 'tools/include/uapi/linux/bpf.h' differs from latest version at 'include/uapi/linux/bpf.h'
> >     CC       util/cs-etm-decoder/cs-etm-decoder.o
> >     CC       util/intel-pt.o
> >   util/cs-etm-decoder/cs-etm-decoder.c: In function 'cs_etm_decoder__buffer_packet':
> >   util/cs-etm-decoder/cs-etm-decoder.c:287:24: error: 'traceid_list' undeclared (first use in this function); did you mean 'trace_event'?
> >     inode = intlist__find(traceid_list, trace_chan_id);
> >                           ^~~~~~~~~~~~
> >                           trace_event
> >   util/cs-etm-decoder/cs-etm-decoder.c:287:24: note: each undeclared identifier is reported only once for each function it appears in
> >   make[6]: *** [/build/linux-stable/tools/build/Makefile.build:97: util/cs-etm-decoder/cs-etm-decoder.o] Error 1
> >   make[5]: *** [/build/linux-stable/tools/build/Makefile.build:139: cs-etm-decoder] Error 2
> >   make[5]: *** Waiting for unfinished jobs....
> >   make[4]: *** [/build/linux-stable/tools/build/Makefile.build:139: util] Error 2
> >   make[3]: *** [Makefile.perf:633: libperf-in.o] Error 2
> >   make[2]: *** [Makefile.perf:206: sub-make] Error 2
> >   make[1]: *** [Makefile:70: all] Error 2
> >   make: *** [Makefile:77: perf] Error 2
> >
> > Link: https://lore.kernel.org/stable/20201114083501.GA468764@eldamar.lan/
> > Cc: Leo Yan <leo.yan@linaro.org>
> > Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
> > Cc: Jiri Olsa <jolsa@redhat.com>
> > Cc: Mark Rutland <mark.rutland@arm.com>
> > Cc: Namhyung Kim <namhyung@kernel.org>
> > Cc: Peter Zijlstra <peterz@infradead.org>
> > Cc: Suzuki Poulouse <suzuki.poulose@arm.com>
> > Cc: Tor Jeremiassen <tor@ti.com>
> > Cc: linux-arm-kernel@lists.infradead.org
> > Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
> > Cc: Guenter Roeck <linux@roeck-us.net>
> > Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> > Cc: <stable@vger.kernel.org> # 4.19.y
> > Signed-off-by: Salvatore Bonaccorso <carnil@debian.org>
> > ---
> >  tools/perf/util/cs-etm.c | 3 ---
> >  tools/perf/util/cs-etm.h | 3 +++
> >  2 files changed, 3 insertions(+), 3 deletions(-)
> >
> > diff --git a/tools/perf/util/cs-etm.c b/tools/perf/util/cs-etm.c
> > index ad33b99f5d21..7b5e15cc6b71 100644
> > --- a/tools/perf/util/cs-etm.c
> > +++ b/tools/perf/util/cs-etm.c
> > @@ -87,9 +87,6 @@ struct cs_etm_queue {
> >         struct cs_etm_packet *packet;
> >  };
> >
> > -/* RB tree for quick conversion between traceID and metadata pointers */
> > -static struct intlist *traceid_list;
> > -
> >  static int cs_etm__update_queues(struct cs_etm_auxtrace *etm);
> >  static int cs_etm__process_timeless_queues(struct cs_etm_auxtrace *etm,
> >                                            pid_t tid, u64 time_);
> > diff --git a/tools/perf/util/cs-etm.h b/tools/perf/util/cs-etm.h
> > index c7ef97b198c7..37f8d48179ca 100644
> > --- a/tools/perf/util/cs-etm.h
> > +++ b/tools/perf/util/cs-etm.h
> > @@ -53,6 +53,9 @@ enum {
> >         CS_ETMV4_PRIV_MAX,
> >  };
> >
> > +/* RB tree for quick conversion between traceID and CPUs */
> > +struct intlist *traceid_list;
> > +
> >  #define KiB(x) ((x) * 1024)
> >  #define MiB(x) ((x) * 1024 * 1024)
> >
> > --
> > 2.29.2
> >
> 
> 
> -- 
> Regards,
> Andrey.

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