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Subject: Re: [PATCH 00/18] drivers: Remove oprofile and dcookies
To:     Robert Richter <rric@kernel.org>,
        Linus Torvalds <torvalds@linux-foundation.org>,
        Viresh Kumar <viresh.kumar@linaro.org>
Cc:     Arnd Bergmann <arnd@kernel.org>,
        Vincent Guittot <vincent.guittot@linaro.org>,
        linux-kernel@vger.kernel.org, anmar.oueja@linaro.org,
        oprofile-list@lists.sf.net,
        Alexander Viro <viro@zeniv.linux.org.uk>
References: <cover.1610622251.git.viresh.kumar@linaro.org>
 <YAC8sf6v8+QAXHD3@rric.localdomain>
From:   William Cohen <wcohen@redhat.com>
Message-ID: <927ed742-914c-bbc2-d397-dabaaa6643e7@redhat.com>
Date:   Fri, 15 Jan 2021 10:44:28 -0500
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On 1/14/21 4:50 PM, Robert Richter wrote:
> On 14.01.21 17:04:24, Viresh Kumar wrote:
>> Hello,
>>
>> The "oprofile" user-space tools don't use the kernel OPROFILE support
>> any more, and haven't in a long time. User-space has been converted to
>> the perf interfaces.
>>
>> Remove oprofile and dcookies (whose only user is oprofile) support from
>> the kernel.
>>
>> This was suggested here [1] earlier.
>>
>> This is build/boot tested by kernel test robot (Intel) and Linaro's
>> Tuxmake[2] for a lot of architectures and no failures were reported.
>>
>> --
>> Viresh
>>
>> [1] https://lore.kernel.org/lkml/CAHk-=whw9t3ZtV8iA2SJWYQS1VOJuS14P_qhj3v5-9PCBmGQww@mail.gmail.com/
>> [2] https://lwn.net/Articles/841624/
>>
>> Viresh Kumar (18):
>>   arch: alpha: Remove CONFIG_OPROFILE support
>>   arch: arm: Remove CONFIG_OPROFILE support
>>   arch: arc: Remove CONFIG_OPROFILE support
>>   arch: hexagon: Don't select HAVE_OPROFILE
>>   arch: ia64: Remove CONFIG_OPROFILE support
>>   arch: ia64: Remove rest of perfmon support
>>   arch: microblaze: Remove CONFIG_OPROFILE support
>>   arch: mips: Remove CONFIG_OPROFILE support
>>   arch: parisc: Remove CONFIG_OPROFILE support
>>   arch: powerpc: Stop building and using oprofile
>>   arch: powerpc: Remove oprofile
>>   arch: s390: Remove CONFIG_OPROFILE support
>>   arch: sh: Remove CONFIG_OPROFILE support
>>   arch: sparc: Remove CONFIG_OPROFILE support
>>   arch: x86: Remove CONFIG_OPROFILE support
>>   arch: xtensa: Remove CONFIG_OPROFILE support
>>   drivers: Remove CONFIG_OPROFILE support
>>   fs: Remove dcookies support
> 
> After oprofile userland moved to version 1.x, the kernel support for
> it isn't needed anymore. The switch was back in 2014 when oprofile
> started using the perf syscall:
> 
>  https://sourceforge.net/p/oprofile/oprofile/ci/ba9edea2bdfe2c9475749fc83105632bd916b96c
> 
> Since then I haven't received any significant patches to implement new
> features or add support for newer platforms in the kernel. There
> haven't been bug reports sent or questions asked on the mailing list
> for quite a while, which indicates there are no or less users. Users
> (if any) should switch to oprofile 1.x or the perf tool. No need to
> carry kernel support any longer with us.
> 
> So time to get rid of it. For the whole series:
> 
> Acked-by: Robert Richter <rric@kernel.org>

The oprofile daemon that used the older oprofile kernel support was removed before OProfile 1.0 release by the following commit in August 2014:

https://sourceforge.net/p/oprofile/oprofile/ci/0c142c3a096d3e9ec42cc9b0ddad994fea60d135

At this point it makes sense to clean up the kernel and remove this unused code.

Acked-by: William Cohen <wcohen@redhat.com>

> 
> 
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