Re: [PATCH 1/2] perf tools: Introduce memory mapping macros in mman-fix.h

["Wangnan (F)" <wangnan0@huawei.com>]

On 2016/9/6 21:39, Arnaldo Carvalho de Melo wrote:
> Em Tue, Sep 06, 2016 at 09:25:47PM +0800, Wangnan (F) escreveu:
>>
>> On 2016/9/6 20:59, Arnaldo Carvalho de Melo wrote:
>>> Em Tue, Sep 06, 2016 at 05:48:51AM +0000, Wang Nan escreveu:
>>>> tools/perf/trace/beauty/mmap.c, tools/perf/util/event.c and
>>>> tools/perf/util/map.c depend on several macros in mman.h, which
>>>> are lost on old systems like ubuntu 12.04. They are architecture
>>> Not "lost on old systems", changing that to "not present on old systems"
>>>
>>>> dependened macros. Importing ./arch/*/include/uapi/asm/mman.h
>>>> into tools/ is not easy because mman.h for some unusual archs
>>>> (like tile) have extra dependencies.
>>>> This patch introduces only required macros into mman-fix.h.
>>>> Macros list is gotten from tools/perf/trace/beauty/mmap.c.
>>> ok, I'll try keeping the  include/uapi/asm-generic/mman.h and
>>> arch/alpha/include/uapi/asm/mman.h with just what you added, so that at
>>> least the .c files appears as using the headers were those things are
>>> defined in the kernel sources.
>>>
>>> Ah, and good eyes in realizing this is not the same value for all
>>> arches!
>> This is why we have to define these macros for each archs.
>> Your solution in tools/perf/trace/beauty/mmap.c works for
>> x86 only.
>>
>> However, I don't like this patchset because we add 300+
>> lines of code and 22 new files for less than 15 macros,
>> and only one of them I really concern. Moreover, futhre
>> code require more symbols in uapi and we have to add new
>> headers, finally we will clone the whole uapi. We have
>> to stop doing this...
> Why? If we want to support older newer kernels running on older distros,
> which is a valid goal, or recent tool source code on older distros,
> where fallbacks will take place with their older kernels, and if we have
> the build automated for that (I have) then why not keep the tools
> building on as many different userspaces as possible?

Your automated building checker is great. I mean we have
to find a way to stop pulling kernel headers to tools/include.

But since we haven't find such a way, I'll continously improve
this mman.h stuff. As your suggestion, I'll try to put them
in uapi/mman.h, not mman-fix.h. This require a building check
for each arch.

Thank you.