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SubjectRe: [PATCH v2 1/5] perf probe: Split add_perf_probe_events()
Hi Namhyung,

Thanks for this patchset.

Could you plase have a look at patch 5/27 and 6/27 in my newest pull
request?
These 2 patches utilize new probing API to create probe point and collect
probe_trace_events. I'm not very sure I fully understand your design
principle,
especially the cleanup part, because I can see different functions
dealing with
cleanup:

cleanup_perf_probe_events
del_perf_probe_events
clear_perf_probe_event
clear_probe_trace_event

But non of them works perfectly for me.

In bpf_prog_priv__clear() function of 6/27, I copied some code from
cleanup_perf_probe_events(), because I think when destroying bpf programs,
the probe_trace_events should also be cleanuped, but we don't need call
exit_symbol_maps() many times, because we are in 'perf record', and not
sure whether other parts of perf need symbol maps. Otherwise I think
directly
calling cleanup_perf_probe_events() sould be better.

You can find patch from:

http://lkml.kernel.org/n/1441523623-152703-6-git-send-email-wangnan0@huawei.com

http://lkml.kernel.org/n/1441523623-152703-7-git-send-email-wangnan0@huawei.com

Thank you.

On 2015/9/4 20:15, Namhyung Kim wrote:
> The add_perf_probe_events() does 3 things:
>
> 1. convert all perf events to trace events
> 2. add all trace events to kernel
> 3. cleanup all trace events
>
> But sometimes we need to do something with the trace events. So split
> the funtion into three, so that it can access intermediate trace events
> via struct __event_package if needed.
>
> Acked-by: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
> Signed-off-by: Namhyung Kim <namhyung@kernel.org>
> ---
> tools/perf/util/probe-event.c | 39 +++++++++++++++++++++++++++++++++++----
> 1 file changed, 35 insertions(+), 4 deletions(-)
>
> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
> index eb5f18b75402..2c762f41e7a5 100644
> --- a/tools/perf/util/probe-event.c
> +++ b/tools/perf/util/probe-event.c
> @@ -2765,9 +2765,10 @@ struct __event_package {
> int ntevs;
> };
>
> -int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
> +static int convert_perf_probe_events(struct perf_probe_event *pevs, int npevs,
> + struct __event_package **ppkgs)
> {
> - int i, j, ret;
> + int i, ret;
> struct __event_package *pkgs;
>
> ret = 0;
> @@ -2792,12 +2793,21 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
> ret = convert_to_probe_trace_events(pkgs[i].pev,
> &pkgs[i].tevs);
> if (ret < 0)
> - goto end;
> + return ret;
> pkgs[i].ntevs = ret;
> }
> /* This just release blacklist only if allocated */
> kprobe_blacklist__release();
>
> + *ppkgs = pkgs;
> +
> + return 0;
> +}
> +
> +static int apply_perf_probe_events(struct __event_package *pkgs, int npevs)
> +{
> + int i, ret = 0;
> +
> /* Loop 2: add all events */
> for (i = 0; i < npevs; i++) {
> ret = __add_probe_trace_events(pkgs[i].pev, pkgs[i].tevs,
> @@ -2806,7 +2816,16 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
> if (ret < 0)
> break;
> }
> -end:
> + return ret;
> +}
> +
> +static void cleanup_perf_probe_events(struct __event_package *pkgs, int npevs)
> +{
> + int i, j;
> +
> + if (pkgs == NULL)
> + return;
> +
> /* Loop 3: cleanup and free trace events */
> for (i = 0; i < npevs; i++) {
> for (j = 0; j < pkgs[i].ntevs; j++)
> @@ -2815,6 +2834,18 @@ end:
> }
> free(pkgs);
> exit_symbol_maps();
> +}
> +
> +int add_perf_probe_events(struct perf_probe_event *pevs, int npevs)
> +{
> + int ret;
> + struct __event_package *pkgs = NULL;
> +
> + ret = convert_perf_probe_events(pevs, npevs, &pkgs);
> + if (ret == 0)
> + ret = apply_perf_probe_events(pkgs, npevs);
> +
> + cleanup_perf_probe_events(pkgs, npevs);
>
> return ret;
> }




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