From: Christoph Hellwig <hch@infradead.org>
To: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Christoph Hellwig <hch@infradead.org>,
Ulrich Drepper <drepper@akkadia.org>,
arnd@arndb.de, davem@davemloft.net, hverkuil@xs4all.nl,
laurent.pinchart@ideasonboard.com, linux-kernel@vger.kernel.org,
mchehab@redhat.com
Subject: Re: [PATCH] Install kernel-page-flags.h
Date: Mon, 19 Mar 2012 07:32:41 -0400 [thread overview]
Message-ID: <20120319113241.GA13991@infradead.org> (raw)
In-Reply-To: <CACVxJT-73diTvBhDxZ=7VUz2BqaRetdnCUGk3hh+_7gyWXB6Dw@mail.gmail.com>
On Wed, Mar 14, 2012 at 12:40:36PM +0200, Alexey Dobriyan wrote:
> >> Programs using /proc/kpageflags need to know about the various flags. ??The
> >> <linux/kernel-page-flags.h> provides them and the comments in the file
> >> indicate that it is supposed to be used by user-level code. ??But the file
> >> is not installed.
> >>
> >> The patch below installs the headers and marks the unstable flags as
> >> out-of-bounds.
> >
> > I don't think this is a good idea at all. ??Let's shoot the person who
> > added that braindead interface ASAP, and replace it with one printing
> > the flags in ASCII format.
>
> ASCII sucks.
> This interface is not for humans.
But we still can't lock down the page flags for a user interface - they
are a very scare resource and we can't afford to keep them stable due
to userspace poking into internals.
I guess the best we can do is to have a translation table for kernel
internal to external documented flags. Once you export the header with
the meanings it's time to add that table, even if it starts out as a 1:1
mapping.
next prev parent reply other threads:[~2012-03-19 11:32 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2012-03-14 7:26 [PATCH] Install kernel-page-flags.h Ulrich Drepper
2012-03-14 7:58 ` Christoph Hellwig
2012-03-14 8:03 ` Ulrich Drepper
2012-03-14 10:40 ` Alexey Dobriyan
2012-03-19 11:32 ` Christoph Hellwig [this message]
2012-03-19 12:45 ` Alexey Dobriyan
2012-03-25 12:28 ` Ulrich Drepper
Reply instructions:
You may reply publicly to this message via plain-text email
using any one of the following methods:
* Save the following mbox file, import it into your mail client,
and reply-to-all from there: mbox
Avoid top-posting and favor interleaved quoting:
https://en.wikipedia.org/wiki/Posting_style#Interleaved_style
* Reply using the --to, --cc, and --in-reply-to
switches of git-send-email(1):
git send-email \
--in-reply-to=20120319113241.GA13991@infradead.org \
--to=hch@infradead.org \
--cc=adobriyan@gmail.com \
--cc=arnd@arndb.de \
--cc=davem@davemloft.net \
--cc=drepper@akkadia.org \
--cc=hverkuil@xs4all.nl \
--cc=laurent.pinchart@ideasonboard.com \
--cc=linux-kernel@vger.kernel.org \
--cc=mchehab@redhat.com \
/path/to/YOUR_REPLY
https://kernel.org/pub/software/scm/git/docs/git-send-email.html
* If your mail client supports setting the In-Reply-To header
via mailto: links, try the mailto: link
Be sure your reply has a Subject: header at the top and a blank line
before the message body.
This is a public inbox, see mirroring instructions
for how to clone and mirror all data and code used for this inbox