linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: "Theodore Y. Ts'o" <tytso@mit.edu>
To: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: Jason Baron <jbaron@akamai.com>, Will Deacon <will@kernel.org>,
	linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH v3] dynamic_debug: allow to work if debugfs is disabled
Date: Fri, 24 Jan 2020 20:42:31 -0500	[thread overview]
Message-ID: <20200125014231.GI147870@mit.edu> (raw)
In-Reply-To: <20200124072940.GA2909311@kroah.com>

On Fri, Jan 24, 2020 at 08:29:40AM +0100, Greg Kroah-Hartman wrote:
> > It's likely that people who normally use
> > distribution kernels where debugfs is disabled will have scripts which
> > are hard-coded to look in /proc, and then when they build a kernel
> > with debugfs enabled, the /proc entry will go **poof**, and their
> > script will break.
> 
> **poof** they didn't test it :)
> 
> Seriously, I am doing this change to make it _easier_ for those people
> who want debugfs disabled, yet want this type of debugging.  This is
> much better than having no debugging at all.
> 
> Don't put extra complexity in the kernel for when it can be trivially
> handled in userspace, you know this :)

It's also trivial to handle this in the kernel by potentially having
the control file appear in two places.  Consider what it would be like
to explain this in the Linux documentation --- "the control file could
be here, or it could be there", depending on how the kernel is
configured.  The complexity of documenting this, and the complexity in
userspace; and we have to have the code in the source code for the
file to be in the appear in both places *anyway*.

We've done a lot more to maintain userspace backwards compatibility
that Linus demands; and while I recognize this is not exactly the same
thing, being consistent about where to find the control file would be
even *easier* for userspace programmers.  And is it really that hard
to provide this consistency in the kernel?

Cheers,

					- Ted

  reply	other threads:[~2020-01-25  1:42 UTC|newest]

Thread overview: 26+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-01-22  7:43 [PATCH] dynamic_debug: allow to work if debugfs is disabled Greg Kroah-Hartman
2020-01-22  8:03 ` Will Deacon
2020-01-22  8:12   ` Greg Kroah-Hartman
2020-01-22 13:53     ` [PATCH v2] " Greg Kroah-Hartman
2020-01-22 18:56       ` Jason Baron
2020-01-22 19:29         ` Greg Kroah-Hartman
2020-01-22 19:31           ` [PATCH v3] " Greg Kroah-Hartman
2020-01-22 21:43             ` Randy Dunlap
2020-01-23  8:48               ` Greg Kroah-Hartman
2020-01-23  8:50                 ` [PATCH v4] " Greg Kroah-Hartman
2020-01-23  9:36                   ` Will Deacon
2020-01-23 15:53             ` [PATCH v3] " Theodore Y. Ts'o
2020-01-23 17:55               ` Greg Kroah-Hartman
2020-01-24  6:02                 ` Theodore Y. Ts'o
2020-01-24  7:29                   ` Greg Kroah-Hartman
2020-01-25  1:42                     ` Theodore Y. Ts'o [this message]
2020-01-25 17:11                       ` Jonathan Corbet
2020-01-27 22:19                         ` Saravana Kannan
2020-02-09 11:05               ` [PATCH v5] " Greg Kroah-Hartman
2020-02-09 15:53                 ` Joe Perches
2020-02-09 17:03                   ` Greg Kroah-Hartman
2020-02-10 21:11                 ` [PATCH v6] " Greg Kroah-Hartman
2020-02-10 21:15                   ` Randy Dunlap
2020-02-12 21:58                     ` Greg Kroah-Hartman
2020-02-11 11:01                   ` Will Deacon
2020-01-25  0:03 ` [PATCH] " kbuild test robot

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=20200125014231.GI147870@mit.edu \
    --to=tytso@mit.edu \
    --cc=gregkh@linuxfoundation.org \
    --cc=jbaron@akamai.com \
    --cc=kernel-team@android.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=will@kernel.org \
    /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;
as well as URLs for NNTP newsgroup(s).