linux-kernel.vger.kernel.org archive mirror
 help / color / mirror / Atom feed
From: Joe Korty <joe.korty@ccur.com>
To: Robert Love <rml@tech9.net>
Cc: torvalds@osdl.org, akpm@digeo.com, linux-kernel@vger.kernel.org
Subject: Re: [PATCH] protect migration/%d etc from sched_setaffinity
Date: Thu, 31 Jul 2003 19:06:36 -0400	[thread overview]
Message-ID: <20030731230635.GA7852@rudolph.ccur.com> (raw)
In-Reply-To: <1059692548.931.329.camel@localhost>

> On Thu, 2003-07-31 at 15:46, Joe Korty wrote:
> 
> > Lock out users from changing the cpu affinity of those per-cpu system
> > daemons which cannot survive such a change, such as migration/%d.
> > 
> > Passes basic handtest of sched_setaffinity(2) on various locked and
> > unlocked processes on a i386, otherwise untested except by eyeball.
> > 
> > Except for one line in i386, no arch needed any changes to support
> > this patch.
> 
> I have been wondering what to do about processor affinity and kernel
> threads. I just concluded "only root can change it, and we can let root
> stab herself if she really wants to."
> 
> But if this is really an issue, why not just do:
> 
> 	ret = -EINVAL;
> 	if (!p->mm)
> 		goto out_unlock;
> 
> in sys_sched_setaffinity ?
> 
> 	Robert Love


It's not all system daemons, just some of them that need protection.

Keeping the set of locked-down daemons to the smallest possible is
important when one wants to 'set aside' cpus for use only by
specific, need-the-lowest-latency-possible realtime applications.

Joe

  reply	other threads:[~2003-07-31 23:07 UTC|newest]

Thread overview: 23+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2003-07-31 22:46 [PATCH] protect migration/%d etc from sched_setaffinity Joe Korty
2003-07-31 22:47 ` Andrew Morton
2003-07-31 23:11   ` Joe Korty
2003-07-31 23:17     ` Andrew Morton
2003-07-31 23:41       ` Robert Love
2003-08-01  0:01       ` Joe Korty
2003-07-31 23:02 ` Robert Love
2003-07-31 23:06   ` Joe Korty [this message]
2003-07-31 23:18     ` Robert Love
2003-07-31 23:16       ` Joe Korty
2003-07-31 23:27         ` Robert Love
2003-07-31 23:26           ` Joe Korty
2003-07-31 23:18       ` [OT] " J.A. Magallon
2003-07-31 23:37         ` Robert Love
2003-08-01 11:09           ` Eric W. Biederman
2003-08-01 16:15             ` Jamie Lokier
2003-08-01 17:31               ` Eric W. Biederman
2003-08-01 17:55                 ` Jamie Lokier
2003-08-01 18:39                   ` Sean Estabrooks
2003-08-01 17:37             ` Robert Love
     [not found] <20030731224604.GA24887@tsunami.ccur.com.suse.lists.linux.kernel>
2003-07-31 23:17 ` Andi Kleen
2003-07-31 23:30   ` Joe Korty
2003-08-01 10:26 Mikael Pettersson

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=20030731230635.GA7852@rudolph.ccur.com \
    --to=joe.korty@ccur.com \
    --cc=akpm@digeo.com \
    --cc=linux-kernel@vger.kernel.org \
    --cc=rml@tech9.net \
    --cc=torvalds@osdl.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).