From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Sat, 18 Dec 2004 07:50:55 +0100 From: Andi Kleen Subject: Re: [patch] CONFIG_ARCH_HAS_ATOMIC_UNSIGNED Message-ID: <20041218065055.GA5829@wotan.suse.de> References: <20041217061150.GF12049@wotan.suse.de> <20041217163308.GE14229@wotan.suse.de> <20041217193724.GA13542@wotan.suse.de> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org Return-Path: To: Christoph Lameter Cc: Andi Kleen , Dave Hansen , linux-mm@kvack.org List-ID: On Fri, Dec 17, 2004 at 02:11:59PM -0800, Christoph Lameter wrote: > On Fri, 17 Dec 2004, Andi Kleen wrote: > > > On Fri, Dec 17, 2004 at 11:26:49AM -0800, Christoph Lameter wrote: > > > On Fri, 17 Dec 2004, Andi Kleen wrote: > > > > > > > > Put the order of the page there for compound pages instead of having that > > > > > in index? > > > > > > > > That would waste memory on the 64bit architectures that cannot tolerate > > > > 32bit atomic flags or on true 32bit architecture. > > > > > > Would be great to have 64 bit atomic support to fill this hole then. > > > > I think you lost me. How would that help? > > It would fill the hole on 64 bits if atomic_t would have the native word > size. The problem is that that 64bit atomic_t type would end up unaligned. While that would work in theory on x86-64 I suspect it would be slow even there. And it would probably not work anywhere else. And as Dave said they plan to use the upper 32bit of flags for CONFIG_NONLINEAR anyways, so it's not even possible. -Andi -- 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