From mboxrd@z Thu Jan 1 00:00:00 1970 Message-ID: <439CFC67.4030107@yahoo.com.au> Date: Mon, 12 Dec 2005 15:28:23 +1100 From: Nick Piggin MIME-Version: 1.0 Subject: Re: [RFC 1/6] Framework References: <20051210005440.3887.34478.sendpatchset@schroedinger.engr.sgi.com> <20051210005445.3887.94119.sendpatchset@schroedinger.engr.sgi.com> <439CF2A2.60105@yahoo.com.au> <20051212035631.GX11190@wotan.suse.de> <439CF93D.5090207@yahoo.com.au> <20051212042142.GZ11190@wotan.suse.de> In-Reply-To: <20051212042142.GZ11190@wotan.suse.de> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: owner-linux-mm@kvack.org Return-Path: To: Andi Kleen Cc: Christoph Lameter , linux-kernel@vger.kernel.org, Hugh Dickins , linux-mm@kvack.org, Marcelo Tosatti List-ID: Andi Kleen wrote: > On Mon, Dec 12, 2005 at 03:14:53PM +1100, Nick Piggin wrote: >>Cool. That is a patch that should go on top of mine, because most of >>my patch is aimed at moving modifications under interrupts-off sections, > > > That's obsolete then. No it isn't. > With local_t you don't need to turn off interrupts > anymore. > Then you can't use __local_xxx, and so many architectures will use atomic instructions (the ones who don't are the ones with tripled cacheline footprint of this structure). Sure i386 and x86-64 are happy, but this would probably slow down most other architectures. > >>However I'm still worried about the use of locals tripling the cacheline >>size of a hot-path structure on some 64-bit architectures. Probably we >>should get them to try to move to the atomic64 scheme before using >>local_t here. > > > I think the right fix for those is to just change the fallback local_t > to disable interrupts again - that should be a better tradeoff and > when they have a better alternative they can implement it in the arch. > Probably right. > (in fact i did a patch for that too, but considered throwing it away > again because I don't have a good way to test it) > Yep, it will be difficult to test. -- SUSE Labs, Novell Inc. Send instant messages to your online friends http://au.messenger.yahoo.com -- 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: email@kvack.org