Messages in this thread Patch in this message | | | Date | Mon, 29 Jul 2013 16:40:58 -0600 | From | David Ahern <> | Subject | Re: [PATCH] perf: Do not require /lib/modules/* on a guest |
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On 7/15/13 2:27 PM, Jason Wessel wrote: > For some types of work loads and special guest environments, you might > have a kernel that has no kernel modules. The perf kvm record tool > fails instantiate vmlinux maps when the kernel modules directory > cannot be opened, even though the kallsyms has been properly > processed. This leads to a perf kvm report that has no guest symbols > resolved.
Theoretically, use of modules is an option:
if (symbol_conf.use_modules && machine__create_modules(machine) < 0) { ... }
But, the use_modules option was flipped from false to true by b32d133a back in 2009. And the lack of complaints suggests this ominous warning in perf-report, diff and annotate is moot:
OPT_BOOLEAN('m', "modules", &symbol_conf.use_modules, "load module symbols - WARNING: use only with -k and LIVE kernel"),
> > This patch changes the failure to locate kernel modules to be > non-fatal. > > Signed-off-by: Jason Wessel <jason.wessel@windriver.com> > --- > tools/perf/util/machine.c | 5 ++++- > 1 file changed, 4 insertions(+), 1 deletion(-) > > diff --git a/tools/perf/util/machine.c b/tools/perf/util/machine.c > index b2ecad6..eb9ebd6 100644 > --- a/tools/perf/util/machine.c > +++ b/tools/perf/util/machine.c > @@ -808,7 +808,10 @@ static int machine__create_modules(struct machine *machine) > free(line); > fclose(file); > > - return machine__set_modules_path(machine); > + if (machine__set_modules_path(machine) < 0) { > + pr_debug("Problems setting modules path maps, continuing anyway...\n"); > + } > + return 0; > > out_delete_line: > free(line);
Acked-by: David Ahern <dsahern@gmail.com>
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