Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S263057AbUKTCvU (ORCPT ); Fri, 19 Nov 2004 21:51:20 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S263088AbUKTCuY (ORCPT ); Fri, 19 Nov 2004 21:50:24 -0500 Received: from smtp203.mail.sc5.yahoo.com ([216.136.129.93]:2396 "HELO smtp203.mail.sc5.yahoo.com") by vger.kernel.org with SMTP id S263057AbUKTCqV (ORCPT ); Fri, 19 Nov 2004 21:46:21 -0500 Message-ID: <419EAFF3.80206@yahoo.com.au> Date: Sat, 20 Nov 2004 13:46:11 +1100 From: Nick Piggin User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.7.2) Gecko/20040820 Debian/1.7.2-4 X-Accept-Language: en MIME-Version: 1.0 To: William Lee Irwin III CC: Linus Torvalds , Christoph Lameter , akpm@osdl.org, Benjamin Herrenschmidt , Hugh Dickins , linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: page fault scalability patch V11 [0/7]: overview References: <419D581F.2080302@yahoo.com.au> <419D5E09.20805@yahoo.com.au> <1100848068.25520.49.camel@gaston> <20041120020306.GA2714@holomorphy.com> <419EAB21.8020207@yahoo.com.au> <20041120024104.GE2714@holomorphy.com> In-Reply-To: <20041120024104.GE2714@holomorphy.com> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1543 Lines: 41 William Lee Irwin III wrote: > William Lee Irwin III wrote: > >>>Unprivileged triggers for full-tasklist scans are NMI oops material. > > > On Sat, Nov 20, 2004 at 01:25:37PM +1100, Nick Piggin wrote: > >>What about pushing the per-thread rss delta back into the global atomic >>rss counter in each schedule()? >>Pros: >>This would take the task exiting problem into its stride as a matter of >>course. >>Single atomic read to get rss. >>Cons: >>would just be moving the atomic op somewhere else if we don't get >>many page faults per schedule. >>Not really nice dependancies. >>Assumes schedule (not context switch) must occur somewhat regularly. >>At present this is not true for SCHED_FIFO tasks. >>Too nasty? > > > This doesn't sound too hot. There's enough accounting that can't be > done anywhere but schedule(), and this can be done elsewhere. Plus, > you're moving an already too-frequent operation to a more frequent > callsite. > No, it won't somehow increase the number of atomic rss operations just because schedule is called more often. The number of ops will be at _most_ the number of page faults. But I agree with your overall evaluation of its 'hotness'. Just another idea. Give this monkey another thousand years at the keys and he'll come up with the perfect solution :P - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/