From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1752217Ab2LVCm6 (ORCPT ); Fri, 21 Dec 2012 21:42:58 -0500 Received: from out01.mta.xmission.com ([166.70.13.231]:43893 "EHLO out01.mta.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752060Ab2LVCmy (ORCPT ); Fri, 21 Dec 2012 21:42:54 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Konrad Rzeszutek Wilk Cc: Yinghai Lu , Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , Andrew Morton , linux-kernel@vger.kernel.org References: <1355814959-10573-1-git-send-email-yinghai@kernel.org> <1355814959-10573-25-git-send-email-yinghai@kernel.org> <20121222023741.GF3468@phenom.dumpdata.com> Date: Fri, 21 Dec 2012 18:42:47 -0800 In-Reply-To: <20121222023741.GF3468@phenom.dumpdata.com> (Konrad Rzeszutek Wilk's message of "Fri, 21 Dec 2012 21:37:41 -0500") Message-ID: <87bodmhkns.fsf@xmission.com> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/24.1 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain X-XM-AID: U2FsdGVkX18m/2mrTqCnMrlEOPStt99ti99aLqVJSFI= X-SA-Exim-Connect-IP: 98.207.153.68 X-SA-Exim-Mail-From: ebiederm@xmission.com X-Spam-Report: * -1.0 ALL_TRUSTED Passed through trusted hosts only via SMTP * 0.0 T_TM2_M_HEADER_IN_MSG BODY: T_TM2_M_HEADER_IN_MSG * -3.0 BAYES_00 BODY: Bayes spam probability is 0 to 1% * [score: 0.0000] * -0.0 DCC_CHECK_NEGATIVE Not listed in DCC * [sa07 1397; Body=1 Fuz1=1 Fuz2=1] X-Spam-DCC: XMission; sa07 1397; Body=1 Fuz1=1 Fuz2=1 X-Spam-Combo: ;Konrad Rzeszutek Wilk X-Spam-Relay-Country: Subject: Re: [PATCH v7 24/27] x86: Add swiotlb force off support X-SA-Exim-Version: 4.2.1 (built Sun, 08 Jan 2012 03:05:19 +0000) X-SA-Exim-Scanned: Yes (on in02.mta.xmission.com) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Konrad Rzeszutek Wilk writes: > On Mon, Dec 17, 2012 at 11:15:56PM -0800, Yinghai Lu wrote: >> So use could disable swiotlb from command line, even swiotlb support >> is compiled in. Just like we have intel_iommu=on and intel_iommu=off. > > You really need to spell out why this is useful. YH why can't we safely autodetect that the swiotlb is unusable when there is no memory below 4G free? Eric