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Date:   Wed, 24 Feb 2021 09:33:28 +0100
From:   Jessica Yu <jeyu@kernel.org>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Christoph Hellwig <hch@lst.de>,
        Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        =?utf-8?B?77+8TWlyb3NsYXY=?= Benes <mbenes@suse.cz>,
        Emil Velikov <emil.l.velikov@gmail.com>,
        Masahiro Yamada <masahiroy@kernel.org>
Subject: Re: [GIT PULL] Modules updates for v5.12
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+++ Linus Torvalds [23/02/21 12:03 -0800]:
>On Tue, Feb 23, 2021 at 12:01 PM Christoph Hellwig <hch@lst.de> wrote:
>>
>> Does your build now enable TRIM_UNUSED_KSYMS but previously didn't by
>> chance?
>
>Crossed emails.
>
>This is plain "make allmodconfig", so yes, now it will enable TRIM_UNUSED_KSYMS.
>
>This is unacceptably slow. If that symbol trimming takes 30% of the
>whole kernel build time, it needs to be fixed or removed.

[ Adding Masahiro to CC ]

It looks like CONFIG_TRIM_UNUSED_KSYMS had been hiding behind
CONFIG_UNUSED_SYMBOLS all this time, and once the EXPORT_UNUSED_SYMBOL
stuff was removed, it exposed that option to be selected by
allyesconfig. That option had previously caused build issues on
powerpc on linux-next, so I had temporarily marked that as BROKEN on
powerpc until Masahiro's fix landed in linux-next. I was not aware of
the additional build slowdown issue :/ In any case, Christoph's
suggestion to invert the option sounds reasonable, since the mips
defconfig selects it, it does not seem totally unused.