From mboxrd@z Thu Jan 1 00:00:00 1970 Date: Tue, 8 Jan 2008 14:08:21 +0000 From: Russell King Subject: Re: [rfc][patch] mm: use a pte bit to flag normal pages Message-ID: <20080108140821.GA8146@flint.arm.linux.org.uk> References: <20071221104701.GE28484@wotan.suse.de> <20080107044355.GA11222@wotan.suse.de> <20080107103028.GA9325@flint.arm.linux.org.uk> <6934efce0801071049u546005e7t7da4311cc0611ccd@mail.gmail.com> <20080107194543.GA2788@flint.arm.linux.org.uk> <1199787075.17809.10.camel@pc1117.cambridge.arm.com> <20080108105227.GA10546@flint.arm.linux.org.uk> <1199800456.17809.72.camel@pc1117.cambridge.arm.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1199800456.17809.72.camel@pc1117.cambridge.arm.com> Sender: owner-linux-mm@kvack.org Return-Path: To: Catalin Marinas Cc: Jared Hulbert , Nick Piggin , Martin Schwidefsky , carsteno@linux.vnet.ibm.com, Heiko Carstens , Linux Memory Management List , linux-arch@vger.kernel.org List-ID: On Tue, Jan 08, 2008 at 01:54:15PM +0000, Catalin Marinas wrote: > On Tue, 2008-01-08 at 10:52 +0000, Russell King wrote: > > It's unclear at present what circumstances you'd use each of the two > > Xscale3 work-around bit combinations - or indeed whether there's a > > printing error in the documentation concerning TEXCB=00101. > > As I said, I don't know the details of this bug and can't comment. As I said I don't think there's anything further that can be usefully added to this discussion until we're further down the road with this. Even though you don't know the details of the bug report, I've mentioned as much as I know about it at present - and that includes with access to Marvells spec update document. When I'm further down the line with PXA3 work maybe I'll know more, but my priority at the moment on PXA3 is suspend/resume support. > I haven't run any benchmarks and I can't say how big the impact is but, > based on some past discussions, 3-4 more cycles in set_pte might go > unnoticed because of other, bigger overheads. Except when you're clearing out page tables - for instance when a thread exits. It's very noticable and shows up rather well in fork+exit tests - even shell scripts. This was certainly the case with 2.2 kernels. Whether 2.6 kernels are soo heavy weight that it's been swapped into non-existence I don't know. -- Russell King Linux kernel 2.6 ARM Linux - http://www.arm.linux.org.uk/ maintainer of: -- 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