From mboxrd@z Thu Jan 1 00:00:00 1970 Subject: Re: preemp / nonpreemp References: From: ebiederm+eric@ccr.net (Eric W. Biederman) Date: 18 Apr 2000 01:40:41 -0500 In-Reply-To: pnilesh@in.ibm.com's message of "Tue, 18 Apr 2000 09:42:27 +0530" Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: owner-linux-mm@kvack.org Return-Path: To: pnilesh@in.ibm.com Cc: linux-mm@kvack.org List-ID: pnilesh@in.ibm.com writes: > The Linux kernel is preemptable. > > Does the preemption mean that inside system calls in kernel a call to > schedule is possible . > Or is there more to it . Well there is the obvious part about being able to prempt user space from a timer tick which gives you most of the work. As far as internally to the kernel on a SMP box unless you are holding the big kernel lock to threads can be running at the same time in kernel. Using the architecture it is also possible to prempt kernel threads that don't hold the big kernel lock on non-SMP systems as well. non-SMP premption probably won't appear until early 2.5 however as it may have a few complications. Eric -- 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.eu.org/Linux-MM/