Messages in this thread | | | Date | Thu, 13 Dec 2018 16:25:51 +0100 | From | Peter Zijlstra <> | Subject | Re: [PATCH v3 perf, bpf-next 1/4] perf, bpf: Introduce PERF_RECORD_BPF_EVENT |
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On Wed, Dec 12, 2018 at 06:56:11PM +0000, Song Liu wrote: > > > > On Dec 12, 2018, at 10:05 AM, Peter Zijlstra <peterz@infradead.org> wrote: > > > > On Wed, Dec 12, 2018 at 05:09:17PM +0000, Song Liu wrote: > >>> And while this tracks the bpf kallsyms, it does not do all kallsyms. > >>> > >>> .... Oooh, I see the problem, everybody is doing their own custom > >>> kallsym_{add,del}() thing, instead of having that in generic code :-( > >>> > >>> This, for example, doesn't track module load/unload nor ftrace > >>> trampolines, even though both affect kallsyms. > >> > >> I think we can use PERF_RECORD_MMAP(or MMAP2) for module load/unload. > >> That could be separate sets of patches. > > > > So I would actually like to move bpf_lock/bpf_kallsyms/bpf_tree + > > bpf_prog_kallsyms_*() + __bpf_address_lookup() into kernel/kallsyms.c > > and also have ftrace use that. > > > > Because currently the ftrace stuff is otherwise invisible. > > > > A generic kallsym register/unregister for any JIT. > > I guess this is _not_ a requirement for this patchset? BPF program has > special data (id, sub_id, tag) that we need PERF_RECORD_BPF_EVENT. So > this patchset should be orthogonal to the generic kallsym framework?
Well, it is a question of ABI. I don't like mixing the kallsym updates with the BPF updates.
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