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From:   Linus Torvalds <torvalds@linux-foundation.org>
Date:   Tue, 23 Feb 2021 12:01:58 -0800
Message-ID: <CAHk-=wjV=OB7_PUWc4XE2vQ64NRWHeXAwhZVrtBqE8-tYrkaFw@mail.gmail.com>
Subject: Re: [GIT PULL] Modules updates for v5.12
To:     Jessica Yu <jeyu@kernel.org>, Christoph Hellwig <hch@lst.de>
Cc:     Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
        =?UTF-8?Q?=EF=BF=BCMiroslav_Benes?= <mbenes@suse.cz>,
        Emil Velikov <emil.l.velikov@gmail.com>
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On Tue, Feb 23, 2021 at 11:55 AM Linus Torvalds
<torvalds@linux-foundation.org> wrote:
>
> I don't see quite what is wrong, but bisection is clear, and points
> the finger at
>
>     367948220fce "module: remove EXPORT_UNUSED_SYMBOL*"
>
> which looks entirely trivial, but clearly isn't.
>
> It's repeatable. That commit slows down my build hugely.

Hmm. I'm starting to suspect that the problem is that the removal of
CONFIG_UNUSED_SYMBOLS now means that we always trigger
CONFIG_TRIM_UNUSED_KSYMS instead.

And then that CONFIG_TRIM_UNUSED_KSYMS is some hugely expensive operation.

                  Linus