Messages in this thread | | | From | Mathieu Poirier <> | Date | Tue, 28 Jul 2020 09:46:59 -0600 | Subject | Re: [PATCH v2 2/2] perf tools: ARM SPE code cleanup |
| |
On Tue, 28 Jul 2020 at 06:02, Arnaldo Carvalho de Melo <acme@kernel.org> wrote: > > Em Mon, Jul 27, 2020 at 02:34:36PM -0600, Mathieu Poirier escreveu: > > On Fri, Jul 24, 2020 at 03:11:11PM +0800, Wei Li wrote: > > > - Firstly, the function auxtrace_record__init() will be invoked only > > > once, the variable "arm_spe_pmus" will not be used afterwards, thus > > > we don't need to check "arm_spe_pmus" is NULL or not; > > > - Another reason is, even though SPE is micro-architecture dependent, > > > but so far it only supports "statistical-profiling-extension-v1" and > > > we have no chance to use multiple SPE's PMU events in Perf command. > > > > I find the above changelog somewhat out of touch with the patch itself. The > > only thing that is happening here is the removal of a useless check and a fix > > for a memory leak. > > Humm, I think the original intent of that code was to cache the results > of find_all_arm_spe_pmus(), as the variable it is assigned to is static.
Correct, but as you pointed out below the function is called only once. And there is still a leak as that memory is never freed.
> > So not a leak, as there was that static reference to it to reuse it > later, but that is strange in a function named "__init()" which usually > is called only once, anyway, so I think that the paragraph with > "Firstly" is kinda ok, but confusing, I think it should read: > > - auxtrace_record__init() is called only once, so there is no point in > using a static variable to cache the results of > find_all_arm_spe_pmus(), make it local and free the results after use.
This is exactly what this patch does and what the changelog should read.
> > The second paragraph is SPE specific, so I'm not qualified to judge on > it. > > I'm replacing the first paragraph with the version I wrote and keep it > in my local branch, please holler if you think I misunderstood. >
There is no point for the next paragraph, it has no relevance to what the code is doing.
Thanks for the editing.
> - Arnaldo > > > Once again whether Arnaldo wants to make the changes by hand or not you may have > > to resubmit. > > > > Reviewed-by: Mathieu Poirier <mathieu.poirier@linaro.org> > > > > > > > > So remove the useless check code to make it clear. > > > > > > Signed-off-by: Wei Li <liwei391@huawei.com> > > > --- > > > tools/perf/arch/arm/util/auxtrace.c | 9 ++++----- > > > 1 file changed, 4 insertions(+), 5 deletions(-) > > > > > > diff --git a/tools/perf/arch/arm/util/auxtrace.c b/tools/perf/arch/arm/util/auxtrace.c > > > index 28a5d0c18b1d..b187bddbd01a 100644 > > > --- a/tools/perf/arch/arm/util/auxtrace.c > > > +++ b/tools/perf/arch/arm/util/auxtrace.c > > > @@ -57,17 +57,15 @@ struct auxtrace_record > > > struct evsel *evsel; > > > bool found_etm = false; > > > struct perf_pmu *found_spe = NULL; > > > - static struct perf_pmu **arm_spe_pmus = NULL; > > > - static int nr_spes = 0; > > > + struct perf_pmu **arm_spe_pmus = NULL; > > > + int nr_spes = 0; > > > int i = 0; > > > > > > if (!evlist) > > > return NULL; > > > > > > cs_etm_pmu = perf_pmu__find(CORESIGHT_ETM_PMU_NAME); > > > - > > > - if (!arm_spe_pmus) > > > - arm_spe_pmus = find_all_arm_spe_pmus(&nr_spes, err); > > > + arm_spe_pmus = find_all_arm_spe_pmus(&nr_spes, err); > > > > > > evlist__for_each_entry(evlist, evsel) { > > > if (cs_etm_pmu && > > > @@ -84,6 +82,7 @@ struct auxtrace_record > > > } > > > } > > > } > > > + free(arm_spe_pmus); > > > > > > if (found_etm && found_spe) { > > > pr_err("Concurrent ARM Coresight ETM and SPE operation not currently supported\n"); > > > -- > > > 2.17.1 > > > > > -- > > - Arnaldo
| |