From: Steven Rostedt <rostedt@goodmis.org>
To: Josh Poimboeuf <jpoimboe@redhat.com>
Cc: Peter Zijlstra <peterz@infradead.org>,
Kairui Song <kasong@redhat.com>, Alexei Starovoitov <ast@fb.com>,
Song Liu <songliubraving@fb.com>,
lkml <linux-kernel@vger.kernel.org>,
Kernel Team <Kernel-team@fb.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
"bpf@vger.kernel.org" <bpf@vger.kernel.org>
Subject: Re: Getting empty callchain from perf_callchain_kernel()
Date: Wed, 12 Jun 2019 09:10:23 -0400 [thread overview]
Message-ID: <20190612091023.6bccf262@gandalf.local.home> (raw)
In-Reply-To: <20190612030501.7tbsjy353g7l74ej@treble>
On Tue, 11 Jun 2019 22:05:01 -0500
Josh Poimboeuf <jpoimboe@redhat.com> wrote:
> Right now, ftrace has a special hook in the ORC unwinder
> (orc_ftrace_find). It would be great if we could get rid of that in
> favor of the "always use frame pointers" approach. I'll hold off on
> doing the kpatch/kprobe trampoline conversions in my patches since it
> would conflict with yours.
Basically, IIUC, what you are saying is that the ftrace trampoline
should always store the %sp in %rb even when CONFIG_FRAME_POINTER is not
enabled? And this can allow you to remove the ftrace specific code from
the orc unwinder?
-- Steve
>
> Though, hm, because of pt_regs I guess ORC would need to be able to
> decode an encoded frame pointer? I was hoping we could leave those
> encoded frame pointers behind in CONFIG_FRAME_POINTER-land forever...
next prev parent reply other threads:[~2019-06-12 13:10 UTC|newest]
Thread overview: 35+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <3CD3EE63-0CD2-404A-A403-E11DCF2DF8D9@fb.com>
[not found] ` <20190517074600.GJ2623@hirez.programming.kicks-ass.net>
[not found] ` <20190517081057.GQ2650@hirez.programming.kicks-ass.net>
[not found] ` <CACPcB9cB5n1HOmZcVpusJq8rAV5+KfmZ-Lxv3tgsSoy7vNrk7w@mail.gmail.com>
[not found] ` <20190517091044.GM2606@hirez.programming.kicks-ass.net>
2019-05-17 18:40 ` Getting empty callchain from perf_callchain_kernel() Song Liu
2019-05-17 21:06 ` Alexei Starovoitov
2019-05-17 21:48 ` Song Liu
2019-05-19 18:07 ` Kairui Song
2019-05-20 17:22 ` Song Liu
2019-05-22 13:51 ` Peter Zijlstra
2019-05-19 18:06 ` Kairui Song
2019-05-20 17:16 ` Song Liu
2019-05-20 17:19 ` Song Liu
2019-05-22 14:02 ` Peter Zijlstra
2019-05-22 14:49 ` Alexei Starovoitov
2019-05-22 17:45 ` Josh Poimboeuf
2019-05-22 23:46 ` Josh Poimboeuf
2019-05-23 6:48 ` Kairui Song
2019-05-23 8:27 ` Song Liu
2019-05-23 9:11 ` Kairui Song
2019-05-23 13:32 ` Josh Poimboeuf
2019-05-23 14:50 ` Kairui Song
2019-05-23 15:24 ` Josh Poimboeuf
2019-05-23 16:41 ` Kairui Song
2019-05-23 17:27 ` Josh Poimboeuf
2019-05-24 2:20 ` Kairui Song
2019-05-24 23:23 ` Josh Poimboeuf
2019-05-27 11:57 ` Kairui Song
2019-06-06 16:04 ` Song Liu
2019-06-06 23:58 ` Josh Poimboeuf
2019-06-11 21:03 ` Josh Poimboeuf
2019-05-24 8:53 ` Peter Zijlstra
2019-05-24 13:05 ` Josh Poimboeuf
2019-06-12 3:05 ` Josh Poimboeuf
2019-06-12 8:54 ` Peter Zijlstra
2019-06-12 14:50 ` Josh Poimboeuf
2019-06-13 20:26 ` Josh Poimboeuf
2019-06-12 13:10 ` Steven Rostedt [this message]
2019-06-12 14:26 ` Josh Poimboeuf
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