From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Wed, 12 Jan 2005 15:54:23 -0800 (PST) From: Christoph Lameter Subject: Re: page table lock patch V15 [0/7]: overview In-Reply-To: <41E5B7AD.40304@yahoo.com.au> Message-ID: References: <41E4BCBE.2010001@yahoo.com.au> <20050112014235.7095dcf4.akpm@osdl.org> <20050112104326.69b99298.akpm@osdl.org> <41E5AFE6.6000509@yahoo.com.au> <20050112153033.6e2e4c6e.akpm@osdl.org> <41E5B7AD.40304@yahoo.com.au> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: owner-linux-mm@kvack.org Return-Path: To: Nick Piggin Cc: Andrew Morton , torvalds@osdl.org, ak@muc.de, hugh@veritas.com, linux-mm@kvack.org, linux-ia64@vger.kernel.org, linux-kernel@vger.kernel.org, benh@kernel.crashing.org List-ID: On Thu, 13 Jan 2005, Nick Piggin wrote: > Note that this was with my ptl removal patches. I can't see why Christoph's > would have _any_ extra overhead as they are, but it looks to me like they're > lacking in atomic ops. So I'd expect something similar for Christoph's when > they're properly atomic. Pointer operations and word size operations are atomic. So this is mostly okay. The issue arises on architectures that have a large pte size than the wordsize. This is only on i386 PAE mode and S/390. S/390 falls back to the page table lock for these operations. PAE mode should do the same and not use atomic ops if they cannot be made to work in a reasonable manner. -- 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