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SubjectRe: [PATCH 28/31] perf probe: Init symbol as kprobe


On 2015/9/2 4:11, Arnaldo Carvalho de Melo wrote:
> Em Sat, Aug 29, 2015 at 04:22:02AM +0000, Wang Nan escreveu:
>> Before this patch, add_perf_probe_events() init symbol maps only for
>> uprobe if the first 'struct perf_probe_event' passed to it is a uprobe
>> event. This is a trick because 'perf probe''s command line syntax
>> constrains the first elements of the probe_event arrays must be kprobes
>> if there is one kprobe there.
>>
>> However, with the incoming BPF uprobe support, that constrain is not
>> hold since 'perf record' will also probe on k/u probes through BPF
>> object, and is possible to pass an array with kprobe but the first
>> element is uprobe.
>>
>> This patch init symbol maps for kprobes even if all of events are
>> uprobes, because the extra cost should be small enough.
> Masami, are you Ok with this one?

I think he would be okay with it because it is his idea :)

Please refer to: http://lkml.kernel.org/n/558E5F42.1060705@hitachi.com

Thank you.
> - Arnaldo
>
>> Signed-off-by: Wang Nan <wangnan0@huawei.com>
>> Cc: Alexei Starovoitov <ast@plumgrid.com>
>> Cc: Brendan Gregg <brendan.d.gregg@gmail.com>
>> Cc: Daniel Borkmann <daniel@iogearbox.net>
>> Cc: David Ahern <dsahern@gmail.com>
>> Cc: He Kuang <hekuang@huawei.com>
>> Cc: Jiri Olsa <jolsa@kernel.org>
>> Cc: Kaixu Xia <xiakaixu@huawei.com>
>> Cc: Masami Hiramatsu <masami.hiramatsu.pt@hitachi.com>
>> Cc: Namhyung Kim <namhyung@kernel.org>
>> Cc: Paul Mackerras <paulus@samba.org>
>> Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
>> Cc: Zefan Li <lizefan@huawei.com>
>> Cc: pi3orama@163.com
>> Cc: Arnaldo Carvalho de Melo <acme@redhat.com>
>> Link: http://lkml.kernel.org/n/1436445342-1402-39-git-send-email-wangnan0@huawei.com
>> ---
>> tools/perf/util/probe-event.c | 2 +-
>> 1 file changed, 1 insertion(+), 1 deletion(-)
>>
>> diff --git a/tools/perf/util/probe-event.c b/tools/perf/util/probe-event.c
>> index e720913..b94a8d7 100644
>> --- a/tools/perf/util/probe-event.c
>> +++ b/tools/perf/util/probe-event.c
>> @@ -2789,7 +2789,7 @@ int add_perf_probe_events(struct perf_probe_event *pevs, int npevs,
>> {
>> int i, ret;
>>
>> - ret = init_symbol_maps(pevs->uprobes);
>> + ret = init_symbol_maps(false);
>> if (ret < 0)
>> return ret;
>>
>> --
>> 2.1.0




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