From mboxrd@z Thu Jan 1 00:00:00 1970 From: Paul Jackson Date: Thu, 25 Sep 2003 05:39:44 +0000 Subject: Re: [Lse-tech] Re: CPUSET Proposal Message-Id: List-Id: References: In-Reply-To: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: linux-ia64@vger.kernel.org > BTW: What do cpusets provide that couldn't be done with user-level > tools on top of the existing sched_setaffinity() system call? I don't see how you can do the migrate_cpuset_processes() from a user level daemon. Just because two tasks happen to be allowed on the same CPUs doesn't mean they are in the same cpuset. The kernel must track, across forks, which tasks share a given cpuset. There are also some resource management capabilities, such as tracking and controlling how much memory a cpuset takes, and swapping (with possible oom kill) against a cpuset that one can consider extending this to, but only if it's in the kernel. But I'm not ready to push this point ... yet. And the permission model has to remain a rather primitive "root can do anything, anyone else can just subset their parent" if it lacks kernel hooks to track uid/suid ownership of each cpuset. -- I won't rest till it's the best ... Programmer, Linux Scalability Paul Jackson 1.650.933.1373