From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 12 Jan 2005 12:43:10 +0000 (GMT) From: Hugh Dickins Subject: Re: page table lock patch V15 [0/7]: overview In-Reply-To: <20050112014235.7095dcf4.akpm@osdl.org> Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Sender: owner-linux-mm@kvack.org Return-Path: To: Andrew Morton Cc: Nick Piggin , clameter@sgi.com, torvalds@osdl.org, ak@muc.de, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org List-ID: On Wed, 12 Jan 2005, Andrew Morton wrote: > Nick Piggin wrote: > > > > Christoph Lameter wrote: > > > Changes from V14->V15 of this patch: > > > > I wonder what everyone thinks about moving forward with these patches? > > I was waiting for them to settle down before paying more attention. They seem to have settled down, without advancing to anything satisfactory. 7/7 is particularly amusing at the moment (added complexity with no payoff). > My general take is that these patches address a single workload on > exceedingly rare and expensive machines. Well put. Christoph's patches stubbornly remain a _good_ hack for one very specific initial workload (multi-parallel faulting of anon memory) on one architecture (ia64, perhaps a few more) important to SGI. I don't see why the mainline kernel should want them. > If they adversely affect common > and cheap machines via code complexity, memory footprint or via runtime > impact then it would be pretty hard to justify their inclusion. Aside from 7/7 (and some good asm primitives within headers), the code itself is not complex; but it is more complex to think about, and so less obviously correct. > Do we have measurements of the negative and/or positive impact on smaller > machines? I don't think so. But my main worry remains the detriment to other architectures, which still remains unaddressed. Nick's patches (I've not seen for some while) are a different case: on the minus side, considerably more complex; on the plus side, more general and more aware of the range of architectures. I'll write at greater length to support these accusations later on. Hugh -- 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