From mboxrd@z Thu Jan 1 00:00:00 1970 From: Daniel Phillips Subject: Re: 2.5.74-mm1 Date: Sun, 6 Jul 2003 04:14:34 +0200 References: <20030703023714.55d13934.akpm@osdl.org> <200307060010.26002.phillips@arcor.de> <20030706012857.GA29544@mail.jlokier.co.uk> In-Reply-To: <20030706012857.GA29544@mail.jlokier.co.uk> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200307060414.34827.phillips@arcor.de> Sender: owner-linux-mm@kvack.org Return-Path: To: Jamie Lokier Cc: Andrew Morton , linux-kernel@vger.kernel.org, linux-mm@kvack.org List-ID: On Sunday 06 July 2003 03:28, Jamie Lokier wrote: > Daniel Phillips wrote: > > What are you going to do if you have one > > application you want to take priority, re-nice the other 50? > > Is that effective? It might be just the trick. Point. > > > Something I've often thought would fix this is to allow normal users > > > to set negative priority which is limited to using X% of the CPU - > > > i.e. those tasks would have their priority raised if they spent more > > > than a small proportion of their time using the CPU. > > > > That's essentially SCHED_RR. As I mentioned above, it's not clear > > to me why SCHED_RR requires superuser privilege, since the amount of > > CPU you can burn that way is bounded. Well, the total of all > > SCHED_RR processes would need to be bounded as well, which is > > straightforward. > > Your last point is most important. At the moment, a SCHED_RR process > with a bug will basically lock up the machine, which is totally > inappropriate for a user app. How does the lockup come about? As defined, a single SCHED_RR process could lock up only its own slice of CPU, as far as I can see. Regards, Daniel -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: aart@kvack.org