From mboxrd@z Thu Jan 1 00:00:00 1970 Received: by wa-out-1112.google.com with SMTP id m33so12286223wag.8 for ; Mon, 07 Jan 2008 14:52:04 -0800 (PST) Message-ID: <6934efce0801071452q9011f1cnfa16cef364c13541@mail.gmail.com> Date: Mon, 7 Jan 2008 14:52:04 -0800 From: "Jared Hulbert" Subject: Re: [rfc][patch] mm: use a pte bit to flag normal pages In-Reply-To: <20080107194543.GA2788@flint.arm.linux.org.uk> MIME-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Content-Disposition: inline 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> Sender: owner-linux-mm@kvack.org Return-Path: To: Jared Hulbert , Nick Piggin , Martin Schwidefsky , carsteno@linux.vnet.ibm.com, Heiko Carstens , Linux Memory Management List , linux-arch@vger.kernel.org List-ID: > Currently, Linux is able to setup mappings in kernel space to cover > any combination of settings. However, userspace is much more limited > because we don't carry the additional bits around in the Linux version > of the PTE - and as such shared mmaps on some systems can end up locking > the CPU. > > A few attempts have been made at solving these without using the > additional PTE bits, but they've been less that robust. Do these new ARM implementations use more bits than most archs? Most ARM implementations can spare a PTE bit for this, right? Is the use of these 3 extra bits to cover a few buggy processors or is this caused by consolidating the needs of widely differing architectures? I just can't get over the idea that you _have_ use up all available bits. Oh well. -- 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