Re: [PATCH net-next 1/3] perf: generalize perf_callchain

[Peter Zijlstra]

On Wed, Feb 17, 2016 at 07:58:57PM -0800, Alexei Starovoitov wrote:
> . avoid walking the stack when there is no room left in the buffer
> . generalize get_perf_callchain() to be called from bpf helper

If it does two things it should be two patches.

> Signed-off-by: Alexei Starovoitov <ast@xxxxxxxxxx>
> ---
>  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.