From owner-freebsd-mips@FreeBSD.ORG Wed Aug 29 11:41:40 2012 Return-Path: Delivered-To: mips@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id 2408C106564A for ; Wed, 29 Aug 2012 11:41:40 +0000 (UTC) (envelope-from c.jayachandran@gmail.com) Received: from mail-wi0-f178.google.com (mail-wi0-f178.google.com [209.85.212.178]) by mx1.freebsd.org (Postfix) with ESMTP id A375E8FC16 for ; Wed, 29 Aug 2012 11:41:39 +0000 (UTC) Received: by wibhr14 with SMTP id hr14so389731wib.13 for ; Wed, 29 Aug 2012 04:41:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20120113; h=mime-version:in-reply-to:references:date:message-id:subject:from:to :cc:content-type; bh=dMyd87p1JKf689ZPPrJn8TuTto0/Vc8THNP8setmDCI=; b=fm1AXVtyeHfcqVTSnvbVUuWkAmMyHMEFIxK5k0jf+DhWlnNOrbwsGka3SjPDsvKLLT +P2mxdSqeMGpBNYKQB3ZVvxTUaof+Nvm+HZrqax45bAkOani3ncJivf4aBPr191S7bsi +tGAnqTOX0Psln2yo5wSog9KKNwVsRM4r6KtiW4LizYmy+4tgwpAK6xPdJbYCGPSfQO9 nxvwl56VINO6TxjSt/x0CxY6I02nUYpRQHfQ/s+Rmv3xOv+xUG9dY1AlipQ4DzdJn2aT tFFjhR/PM1UZrLsUvxKMMw7n5Ye25q8T+3CzBNQJiaT0eCEqz5RV2zZvGcuu3i+r8E3H ZQqA== MIME-Version: 1.0 Received: by 10.216.123.130 with SMTP id v2mr805547weh.117.1346240498441; Wed, 29 Aug 2012 04:41:38 -0700 (PDT) Received: by 10.216.115.3 with HTTP; Wed, 29 Aug 2012 04:41:38 -0700 (PDT) In-Reply-To: <503AF695.9060405@rice.edu> References: <50228F5C.1000408@rice.edu> <50269AD4.9050804@rice.edu> <5029635A.4050209@rice.edu> <502D2271.6080105@rice.edu> <503AF695.9060405@rice.edu> Date: Wed, 29 Aug 2012 17:11:38 +0530 Message-ID: From: "Jayachandran C." To: Alan Cox Content-Type: text/plain; charset=ISO-8859-1 Cc: mips@freebsd.org Subject: Re: mips pmap patch X-BeenThere: freebsd-mips@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Porting FreeBSD to MIPS List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 29 Aug 2012 11:41:40 -0000 On Mon, Aug 27, 2012 at 9:54 AM, Alan Cox wrote: > Could you please test the attached patch? For a change, this patch is an > optimization (as opposed to a bug fix). It carves off a third high-order > bit from the PTE in order to implement another software flag. For 64-bit > systems, this bit was previously unused. For 32-bit systems, this patch > effectively reduces the size of the PTE's page frame number (PFN) field by 1 > bit. However, the PFN still has more than enough bits to support the 32-bit > vm_paddr_t. > > This patch needs both 32-bit and 64-bit testing. I'm fairly confident of > the correctness of the 64-bit case, but less so of the 32-bit case. Tested this on both 32 and 64 bit configuration on XLP and no problems were seen. > Going forward, I expect to claim a fourth bit from the PTE in order to > implement a proper access bit emulation. Regards, JC