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Date:   Tue, 23 Feb 2021 21:01:30 +0100
From:   Christoph Hellwig <hch@lst.de>
To:     Linus Torvalds <torvalds@linux-foundation.org>
Cc:     Jessica Yu <jeyu@kernel.org>, 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>
Subject: Re: [GIT PULL] Modules updates for v5.12
Message-ID: <20210223200130.GA8059@lst.de>
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On Tue, Feb 23, 2021 at 11:55:50AM -0800, Linus Torvalds wrote:
> On Tue, Feb 23, 2021 at 10:42 AM Linus Torvalds
> <torvalds@linux-foundation.org> wrote:
> >
> > I think there is something horribly wrong in my tree, and my build
> > process is now about 30% slower. It went from 5+ minutes to 8+
> > minutes. The main suspect would be some lack of parallelism.
> 
> 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.

Does your build now enable TRIM_UNUSED_KSYMS but previously didn't by
chance?

> 
>               Linus
---end quoted text---