From owner-freebsd-current@FreeBSD.ORG Mon Mar 22 05:53:20 2010 Return-Path: Delivered-To: freebsd-current@freebsd.org Received: from mx1.freebsd.org (mx1.freebsd.org [IPv6:2001:4f8:fff6::34]) by hub.freebsd.org (Postfix) with ESMTP id E5782106566B; Mon, 22 Mar 2010 05:53:20 +0000 (UTC) (envelope-from mavbsd@gmail.com) Received: from mail-fx0-f209.google.com (mail-fx0-f209.google.com [209.85.220.209]) by mx1.freebsd.org (Postfix) with ESMTP id 3FDCF8FC0C; Mon, 22 Mar 2010 05:53:19 +0000 (UTC) Received: by fxm1 with SMTP id 1so4966687fxm.33 for ; Sun, 21 Mar 2010 22:53:19 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=gamma; h=domainkey-signature:received:received:sender:message-id:date:from :user-agent:mime-version:to:cc:subject:references:in-reply-to :x-enigmail-version:content-type:content-transfer-encoding; bh=LjlcvBytxdFQIJQwccw31J8lb75cHk6eQciz2IhvwG8=; b=SepHsS2rn5zJs84hWeqxl4zmqXBpYpATOv7BBjkTEYM8gF5vlXiXnRCh5u1/VRzgfL tCugsD+97NuC2I5uyvINHcFTjtjYhFwiQRVIeKJGVRvBkNyju4QWFDT4GXEHL/YKJPf8 CszrVTT3nxcAXPWSPyKS/jkDOCE4K4PB8ohu4= DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=sender:message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:x-enigmail-version:content-type :content-transfer-encoding; b=vCkXmbo8zXDVgMBKWi0I26CY5GGVhFdjYp2dV1Zudo11qqLLCoABj9b9j/KoCVlBOt lq95kS7wr2tu9ZywI7dhtWBv7+Qa8uzJomtwNNNHyTjBOGtrN37ssghh3JIxEiLzdvBa WyBzJoUTlPc8ucrTc5Tu0gxZqABaDGeG4UWRA= Received: by 10.223.5.75 with SMTP id 11mr3756400fau.46.1269237199101; Sun, 21 Mar 2010 22:53:19 -0700 (PDT) Received: from mavbook.mavhome.dp.ua (pc.mavhome.dp.ua [212.86.226.226]) by mx.google.com with ESMTPS id 14sm3294631fxm.13.2010.03.21.22.53.17 (version=SSLv3 cipher=RC4-MD5); Sun, 21 Mar 2010 22:53:18 -0700 (PDT) Sender: Alexander Motin Message-ID: <4BA705CB.9090705@FreeBSD.org> Date: Mon, 22 Mar 2010 07:53:15 +0200 From: Alexander Motin User-Agent: Thunderbird 2.0.0.23 (X11/20091212) MIME-Version: 1.0 To: jhell References: <4BA4E7A9.3070502@FreeBSD.org> <201003201753.o2KHrH5x003946@apollo.backplane.com> <891E2580-8DE3-4B82-81C4-F2C07735A854@samsco.org> <4BA52179.9030903@FreeBSD.org> <4BA532FF.6040407@elischer.org> <4BA62757.7090400@FreeBSD.org> In-Reply-To: X-Enigmail-Version: 0.96.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Cc: FreeBSD-Current , freebsd-arch@freebsd.org Subject: Re: Increasing MAXPHYS X-BeenThere: freebsd-current@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Discussions about the use of FreeBSD-current List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Mon, 22 Mar 2010 05:53:21 -0000 jhell wrote: > On Sun, 21 Mar 2010 20:54, jhell@ wrote: >> I played with it on one re-compile of a kernel and for the sake of it >> DFLTPHYS=128 MAXPHYS=256 and found out that I could not cause a crash >> dump to be performed upon request (reboot -d) due to the boundary >> being hit for DMA which is 65536. Obviously this would have to be >> adjusted in ata-dma.c. >> >> I suppose that there would have to be a better way to get the real >> allowable boundary from the running system instead of setting it >> statically. >> >> Other then the above I do not see a reason why not... It is HEAD and >> this is the type of experimental stuff it was meant for. > > I should have also said that I also repeated the above without setting > DFLTPHYS and setting MAXPHYS to 256. It was bad idea to increase DFLTPHYS. It is not intended to be increased. About DMA boundary, I do not very understand the problem. Yes, legacy ATA has DMA boundary of 64K, but there is no problem to submit S/G list of several segments. How long ago have you tried it, on which controller and which diagnostics do you have? -- Alexander Motin