From mboxrd@z Thu Jan 1 00:00:00 1970 From: William Lee Irwin III Date: Sat, 20 Nov 2004 02:41:04 +0000 Subject: Re: page fault scalability patch V11 [0/7]: overview Message-Id: <20041120024104.GE2714@holomorphy.com> List-Id: 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> In-Reply-To: <419EAB21.8020207@yahoo.com.au> MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit To: Nick Piggin 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 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. -- wli