From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <419EAFF3.80206@yahoo.com.au> Date: Sat, 20 Nov 2004 13:46:11 +1100 From: Nick Piggin MIME-Version: 1.0 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: owner-linux-mm@kvack.org Return-Path: 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 List-ID: 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, 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