From: Peter Zijlstra Subject: Re: [PATCH net-next 1/3] perf: generalize perf_callchain Date: Thu, 25 Feb 2016 17:48:47 +0100 Message-ID: <20160225164847.GT6356@twins.programming.kicks-ass.net> References: <1455767939-2700534-1-git-send-email-ast@fb.com> <1455767939-2700534-2-git-send-email-ast@fb.com> <20160225141859.GM6357@twins.programming.kicks-ass.net> <56CF2DCE.5010501@fb.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Cc: "David S. Miller" , Ingo Molnar , Steven Rostedt , Wang Nan , Daniel Borkmann , Brendan Gregg , netdev@vger.kernel.org, linux-kernel@vger.kernel.org To: Alexei Starovoitov Return-path: Content-Disposition: inline In-Reply-To: <56CF2DCE.5010501@fb.com> Sender: linux-kernel-owner@vger.kernel.org List-Id: netdev.vger.kernel.org On Thu, Feb 25, 2016 at 08:37:34AM -0800, Alexei Starovoitov wrote: > On 2/25/16 6:18 AM, Peter Zijlstra wrote: > >> arch/x86/include/asm/stacktrace.h | 2 +- > >> arch/x86/kernel/cpu/perf_event.c | 4 ++-- > >> arch/x86/kernel/dumpstack.c | 6 ++++-- > >> arch/x86/kernel/stacktrace.c | 18 +++++++++++------- > >> arch/x86/oprofile/backtrace.c | 3 ++- > >> include/linux/perf_event.h | 13 +++++++++++-- > >> kernel/events/callchain.c | 32 ++++++++++++++++++++------------ > >> kernel/events/internal.h | 2 -- > >> 8 files changed, 51 insertions(+), 29 deletions(-) > > > >And at the very least this should have had a note that it doesn't break > >all the other archs that implement perf-callchain stuff. > > the cross-arch interface is two weak functions > perf_callchain_kernel() and perf_callchain_user() > and back into generic via perf_callchain_store(). > Nothing changes there. The code speaks for itself. > "non-x86 archs are not broken" would be a silly comment. No, a diffstat like that immediately makes me wonder if you've even bothered looking at !x86. A statement to this effect would've shown you did indeed consider it.