[RESEND PATCH 0/5] perf core: Support overwrite ring buffer

[Wang Nan]

This patch set has been posted multiple times (with and without
corresponding 'perf tool' patches), and doesn't receive further
comment. I think it should be okay to merge them into mainline.
There are many perf's improvement depend on it. However, Peter
is not responsive after I fixed some problems he pointed out.

Introduces 'write_backward' into perf_event_attr, allows kernel
writing the ring buffer from the end of it. This feature allows
extracting data from overwritable ring buffer.

Wang Nan (5):
  perf core: Introduce new ioctl options to pause and resume ring buffer
  perf core: Set event's default overflow_handler
  perf core: Prepare writing into ring buffer from end
  perf core: Add backward attribute to perf event
  perf core: Reduce perf event output overhead by new overflow handler

 include/linux/perf_event.h      | 22 +++++++++++--
 include/uapi/linux/perf_event.h |  4 ++-
 kernel/events/core.c            | 73 +++++++++++++++++++++++++++++++++++------
 kernel/events/internal.h        | 11 +++++++
 kernel/events/ring_buffer.c     | 63 +++++++++++++++++++++++++++++++----
 5 files changed, 153 insertions(+), 20 deletions(-)

Cc: He Kuang <hekuang@xxxxxxxxxx>
Cc: Alexei Starovoitov <ast@xxxxxxxxxx>
Cc: Arnaldo Carvalho de Melo <acme@xxxxxxxxxx>
Cc: Brendan Gregg <brendan.d.gregg@xxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxxxxx>
Cc: Jiri Olsa <jolsa@xxxxxxxxxx>
Cc: Masami Hiramatsu <masami.hiramatsu.pt@xxxxxxxxxxx>
Cc: Namhyung Kim <namhyung@xxxxxxxxxx>
Cc: Peter Zijlstra <peterz@xxxxxxxxxxxxx>
Cc: Zefan Li <lizefan@xxxxxxxxxx>
Cc: pi3orama@xxxxxxx

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