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Re: Regression in "kbuild: fix if_change and friends to consider argument order"

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2016-06-07 18:58 GMT+09:00 Michal Marek <mmarek@suse.cz>:
> On 2016-06-07 11:38, Michal Marek wrote:
>> On 2016-06-07 03:38, Zanoni, Paulo R wrote:
>>> Hi
>>>
>>> I recently noticed that alternating between "make" and "make targz-pkg"
>>> rebuilds the whole Kernel. This was not happening before. As a Kernel
>>> developer, my build/install/test environment heavily relies on the fact
>>> that "make targz-pkg" only quickly generates the tarball if everything
>>> is already built, so this change is heavily impacting my development
>>> environment.
>>>
>>> I did some bisection and concluded that the first bad commit is:
>>>
>>> commit 9c8fa9bc08f60ac657751daba9fccf828a36cfed
>>> Author: Masahiro Yamada
>>> Date:   Sat May 7 15:48:26 2016 +0900
>>>     kbuild: fix if_change and friends to consider argument order
>>>
>>> I also verified that if I just revert this commit on top of the
>>> most recent tree it goes back to the usual behavior.
>>>
>>> I read the commit message and it seems that some unneeded rebuilds are
>>> somewhat expected, but I can't understand why such a change in the
>>> command line like the one I did triggers everything to be rebuilt.
>>> IMHO, it really shouldn't. I also wonder that maybe the regression I'm
>>> experiencing was not expected in the original change, so maybe there's
>>> a way to keep the original improvement caused by the mentioned patch
>>> without the regression I'm experiencing.
>>>
>>> How to reproduce (exact commands I used at every bisect step):
>>>
>>> $ make tinyconfig
>>> $ time make -j4 V=2 # this should build things
>>> $ time make -j4 V=2 # just to make sure nothing will be rebuilt
>>> $ time make -j4 V=2 targz-pkg
>>
>> I can reproduce it.
>
> Try the attached patch.
>
> Michal
>


Right.

I had already sent a similar patch.
https://patchwork.kernel.org/patch/9159863/

My concern is it is effectively
reverting e8f5bdb02ce0.
I hope Rik can comment on that.




-- 
Best Regards
Masahiro Yamada

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Regression in "kbuild: fix if_change and friends to consider  argument order" "Zanoni, Paulo R" <paulo.r.zanoni@intel.com> - 2016-06-07 03:40 +0200
  Re: Regression in "kbuild: fix if_change and friends to consider  argument order" Michal Marek <mmarek@suse.com> - 2016-06-07 11:40 +0200
    Re: Regression in "kbuild: fix if_change and friends to consider  argument order" Michal Marek <mmarek@suse.cz> - 2016-06-07 12:00 +0200
      Re: Regression in "kbuild: fix if_change and friends to consider  argument order" Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-06-07 12:10 +0200
        Re: Regression in "kbuild: fix if_change and friends to consider  argument order" Michal Marek <mmarek@suse.cz> - 2016-06-07 12:50 +0200
          Re: Regression in "kbuild: fix if_change and friends to consider  argument order" Masahiro Yamada <yamada.masahiro@socionext.com> - 2016-06-07 13:40 +0200
            Re: Regression in "kbuild: fix if_change and friends to consider  argument order" "Zanoni, Paulo R" <paulo.r.zanoni@intel.com> - 2016-06-07 16:20 +0200
              Re: Regression in "kbuild: fix if_change and friends to consider  argument order" Michal Marek <mmarek@suse.com> - 2016-06-08 00:00 +0200
                Re: Regression in "kbuild: fix if_change and friends to consider  argument order" "Zanoni, Paulo R" <paulo.r.zanoni@intel.com> - 2016-06-09 01:30 +0200

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