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Date: Tue, 8 Jan 2019 02:49:01 +0300
From: Alexey Dobriyan <adobriyan@gmail.com>
To: Daniel Colascione <dancol@google.com>
Cc: Dave Chinner <david@fromorbit.com>,
        Waiman Long <longman@redhat.com>,
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        Randy Dunlap <rdunlap@infradead.org>
Subject: Re: [PATCH 0/2] /proc/stat: Reduce irqs counting performance overhead
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On Mon, Jan 07, 2019 at 05:41:28PM -0500, Daniel Colascione wrote:
> There should be a general-purpose way for /proc file readers to tell
> the kernel which bits of information interest them on a particular read
> syscall sequence or particular open(2) or something.

This opens a pandora box full of ioctls. /proc supports ioctls on files
which aren't /proc/$PID and /proc/sys/* though.

So people made a mess with allegedly easy text files and now they
continue to make even more mess adding ioctls on top.