Re: [PATCH 1/2] perf kvm: Support refcnt in structure kvm_info

Arnaldo Carvalho de Melo
2023-03-21T17:48:26Z

Em Tue, Mar 21, 2023 at 10:22:35PM +0800, Leo Yan escreveu:
> On Tue, Mar 21, 2023 at 10:00:56AM -0300, Arnaldo Carvalho de Melo wrote:
>
> [...]
>
> > > +static inline void __kvm_info__zput(struct kvm_info **ki)
> > > +{
> > > + kvm_info__put(*ki);
> > > + *ki = NULL;
> > > +}
> > > +
> > > +#define kvm_info__zput(ki) __kvm_info__zput(&ki)
> > > +
> > > +static inline struct kvm_info *kvm_info__new(void)
> > > +{
> > > + struct kvm_info *ki;
> > > +
> > > + ki = zalloc(sizeof(*ki));
> > > + if (ki)
> > > + refcount_set(&ki->refcnt, 1);
> > > +
> > > + return ki;
> > > +}
> > > +
> > > #endif /* HAVE_KVM_STAT_SUPPORT */
> > >
> > > extern int kvm_add_default_arch_event(int *argc, const char **argv);
> >
> > I had to add this:
> >
> > Provide a nop version of kvm_info__zput() to be used when
> > HAVE_KVM_STAT_SUPPORT isn't defined as it is used unconditionally in
> > hists__findnew_entry() and hist_entry__delete().
>
> Thanks a lot, Arnaldo.
>
> Just want to check, before I sent out this series I have run building
> test with the command `make -C tools/perf build-test` and I didn't see
> the building failure. Do I need to run other testing?

Yes, but I didn't manage yet to make them public in a way that you could
use it easily :-\

I have a set of perf build containers and in some cases
HAVE_KVM_STAT_SUPPORT isn't defined, thus I noticed the problem.

Since you're working on kvm stat, maybe you could add a way to disable
it from the make command line and then add it to tools/perf/tests/make?

Here is an example of this for something that was opt-in:

⬢[acme@toolbox perf-tools-next]$ git show 9300acc6fed8e957c8d60f6f8e4451b508feea2c
commit 9300acc6fed8e957c8d60f6f8e4451b508feea2c
Author: Arnaldo Carvalho de Melo <acme@redhat.com>
Date: Fri May 29 16:25:34 2020 -0300

perf build: Add a LIBPFM4=1 build test entry

So that when one runs:

$ make -C tools/perf build-test

We make sure that recent changes don't break that opt-in build.

Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Alexei Starovoitov <ast@kernel.org>
Cc: Alexey Budankov <alexey.budankov@linux.intel.com>
Cc: Andi Kleen <ak@linux.intel.com>
Cc: Andrii Nakryiko <andriin@fb.com>
Cc: Daniel Borkmann <daniel@iogearbox.net>
Cc: Florian Fainelli <f.fainelli@gmail.com>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Ian Rogers <irogers@google.com>
Cc: Igor Lubashev <ilubashe@akamai.com>
Cc: Jin Yao <yao.jin@linux.intel.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Jiwei Sun <jiwei.sun@windriver.com>
Cc: John Garry <john.garry@huawei.com>
Cc: Kan Liang <kan.liang@linux.intel.com>
Cc: Leo Yan <leo.yan@linaro.org>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Martin KaFai Lau <kafai@fb.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Stephane Eranian <eranian@google.com>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Yonghong Song <yhs@fb.com>
Cc: yuzhoujian <yuzhoujian@didichuxing.com>
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

diff --git a/tools/perf/tests/make b/tools/perf/tests/make
index 8fe6c7911f46e7ef..9b651dfe0a6b8a91 100644
--- a/tools/perf/tests/make
+++ b/tools/perf/tests/make
@@ -90,6 +90,7 @@ make_with_babeltrace:= LIBBABELTRACE=1
make_no_sdt := NO_SDT=1
make_no_syscall_tbl := NO_SYSCALL_TABLE=1
make_with_clangllvm := LIBCLANGLLVM=1
+make_with_libpfm4 := LIBPFM4=1
make_tags := tags
make_cscope := cscope
make_help := help
@@ -152,6 +153,7 @@ run += make_no_sdt
run += make_no_syscall_tbl
run += make_with_babeltrace
run += make_with_clangllvm
+run += make_with_libpfm4
run += make_help
run += make_doc
run += make_perf_o
⬢[acme@toolbox perf-tools-next]$

----------------------

Look at tools/perf/Makefile.perf and try to add a NO_KVM_STAT=1 perhaps,
and then add it to tools/perf/tests/make so that we catch problems like
the one I found and fixed in this thread.

Thanks,

- Arnaldo