Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1750793AbVJWWXg (ORCPT ); Sun, 23 Oct 2005 18:23:36 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1750796AbVJWWXg (ORCPT ); Sun, 23 Oct 2005 18:23:36 -0400 Received: from smtp.osdl.org ([65.172.181.4]:176 "EHLO smtp.osdl.org") by vger.kernel.org with ESMTP id S1750793AbVJWWXf (ORCPT ); Sun, 23 Oct 2005 18:23:35 -0400 Date: Sun, 23 Oct 2005 15:22:45 -0700 From: Andrew Morton To: hugh@veritas.com, clameter@sgi.com, rmk@arm.linux.org.uk, matthew@wil.cx, jdike@addtoit.com, linux-kernel@vger.kernel.org Subject: Re: [PATCH 7/9] mm: split page table lock Message-Id: <20051023152245.4d1dc812.akpm@osdl.org> In-Reply-To: <20051023142712.6c736dd3.akpm@osdl.org> References: <20051023142712.6c736dd3.akpm@osdl.org> X-Mailer: Sylpheed version 1.0.4 (GTK+ 1.2.10; i386-redhat-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 889 Lines: 22 Andrew Morton wrote: > > Hugh Dickins wrote: > > > > In this implementation, the spinlock is tucked inside the struct page of > > the page table page: with a BUILD_BUG_ON in case it overflows - which it > > would in the case of 32-bit PA-RISC with spinlock debugging enabled. > > eh? It's going to overflow an unsigned long on x86 too: Ah, I think I see what you've done: assume that .index, .lru and .virtual are unused on pagetable pages, so we can just overwrite them. ick. I think I prefer the union, although it'll make struct page bigger for CONFIG_PREEMPT+CONFIG_SMP+NR_CPUS>=4. hmm. - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/