From: "Liang, Kan" <kan.liang@intel.com>
To: Jiri Olsa <jolsa@redhat.com>
CC: "acme@kernel.org" <acme@kernel.org>,
        "peterz@infradead.org" <peterz@infradead.org>,
        "mingo@redhat.com" <mingo@redhat.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "wangnan0@huawei.com" <wangnan0@huawei.com>,
        "jolsa@kernel.org" <jolsa@kernel.org>,
        "namhyung@kernel.org" <namhyung@kernel.org>,
        "ak@linux.intel.com" <ak@linux.intel.com>,
        "yao.jin@linux.intel.com" <yao.jin@linux.intel.com>
Subject: RE: [PATCH V3 07/12] perf mmap: discard legacy interface for mmap
 read
Thread-Topic: [PATCH V3 07/12] perf mmap: discard legacy interface for mmap
 read
Thread-Index: AQHTeohY6eH1Z7sYBECYUGT4pi3x8aNuVQQAgADiZxA=
Date: Thu, 11 Jan 2018 21:28:07 +0000
Message-ID: <37D7C6CF3E00A74B8858931C1DB2F077537FFC0E@SHSMSX103.ccr.corp.intel.com>
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 <20180111142558.GE16655@krava>
In-Reply-To: <20180111142558.GE16655@krava>
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> On Thu, Dec 21, 2017 at 10:08:49AM -0800, kan.liang@intel.com wrote:
> > From: Kan Liang <kan.liang@intel.com>
> >
> > Discards perf_mmap__read_backward and perf_mmap__read_catchup.
> No tools
> > use them.
> >
> > There are tools still use perf_mmap__read_forward. Keep it, but add
> > comments to point to the new interface for future use.
> >
> > Signed-off-by: Kan Liang <kan.liang@intel.com>
> > ---
> >  tools/perf/util/mmap.c | 50 ++++----------------------------------------------
> >  tools/perf/util/mmap.h |  3 ---
> >  2 files changed, 4 insertions(+), 49 deletions(-)
> >
> > diff --git a/tools/perf/util/mmap.c b/tools/perf/util/mmap.c
> > index d0ca3ba..650e0a7 100644
> > --- a/tools/perf/util/mmap.c
> > +++ b/tools/perf/util/mmap.c
> > @@ -63,6 +63,10 @@ static union perf_event *perf_mmap__read(struct
> perf_mmap *map,
> >  	return event;
> >  }
> >
> > +/*
> > + * legacy interface for mmap read.
> > + * Don't use it. Use perf_mmap__read_event().
> > + */
> 
> could we get rid of it then? looks like it's not much work,
> seems it's used only in:
>

To get rid of it, it has to introduce the whole 
perf_mmap__read_init/_read_event/_done.

Besides perf top, kvm and trace need to be changed.
There are also 11 perf test cases need to be changed as well.

I think that would make current patch series too huge.
I can submit a separated patch series later to get rid of
the legacy interface. Is it OK?

Thanks,
Kan
 
>   perf_evlist__mmap_read
>     perf_evlist__mmap_read_forward
> 
> it'd prove the new interface work correctly for both cases
>
> thanks,
> jirka
> 
> >  union perf_event *perf_mmap__read_forward(struct perf_mmap *map)
> >  {
> >  	u64 head;
> > @@ -78,41 +82,6 @@ union perf_event
> *perf_mmap__read_forward(struct perf_mmap *map)
> >  	return perf_mmap__read(map, &map->prev, head);
> >  }
> 
> SNIP