From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754778AbbCEJAU (ORCPT ); Thu, 5 Mar 2015 04:00:20 -0500 Received: from mail.emea.novell.com ([130.57.118.101]:41636 "EHLO mail.emea.novell.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754069AbbCEJAR convert rfc822-to-8bit (ORCPT ); Thu, 5 Mar 2015 04:00:17 -0500 Message-Id: <54F8292E02000078000667F9@mail.emea.novell.com> X-Mailer: Novell GroupWise Internet Agent 14.0.1 Date: Thu, 05 Mar 2015 09:00:14 +0000 From: "Jan Beulich" To: "Xiaoming Wang" Cc: "Liu@aserp2030.oracle.com" , "Zhang@aserp2030.oracle.com" , "chris@chris-wilson.co.uk" , "david.vrabel@citrix.com" , "lauraa@codeaurora.org" , "heiko.carstens@de.ibm.com" , "linux@horizon.com" , "Chuansheng Liu" , "Dongxing Zhang" , "takahiro.akashi@linaro.org" , "akpm@linux-foundation.org" , "linux-mips@linux-mips.org" , "ralf@linux-mips.org" , "xen-devel@lists.xenproject.org" , "boris.ostrovsky@oracle.com" , "Konrad RzeszutekWilk" , "d.kasatkin@samsung.com" , "pebolle@tiscali.nl" , "linux-kernel@vger.kernel.org" Subject: RE: [PATCH v5] modify the IO_TLB_SEGSIZE and IO_TLB_DEFAULT_SIZE configurable as flexible requirement about SW-IOMMU. References: <1425370269-29658-1-git-send-email-xiaoming.wang@intel.com> <20150304194237.GA12884@l.oracle.com> <54F8247B02000078000667AF@mail.emea.novell.com> In-Reply-To: Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 8BIT Content-Disposition: inline Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org >>> On 05.03.15 at 09:52, wrote: >> From: Jan Beulich [mailto:JBeulich@suse.com] >> Sent: Thursday, March 5, 2015 4:40 PM >> >>> On 05.03.15 at 04:53, wrote: >> >> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] >> >> Sent: Thursday, March 5, 2015 3:43 AM On Tue, Mar 03, 2015 at >> >> 04:11:09PM +0800, Wang Xiaoming wrote: >> >> > @@ -101,13 +119,32 @@ setup_io_tlb_npages(char *str) { >> >> > if (isdigit(*str)) { >> >> > io_tlb_nslabs = simple_strtoul(str, &str, 0); >> >> > - /* avoid tail segment of size < IO_TLB_SEGSIZE */ >> >> > - io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); >> >> > } >> >> > if (*str == ',') >> >> > ++str; >> >> > - if (!strcmp(str, "force")) >> >> > + if (!strncmp(str, "force", 5)) { >> >> > swiotlb_force = 1; >> >> > + str += 5; >> >> > + } >> >> >> >> So the format is now: >> >> >> >> Format: { | force | | } >> >> >> >> which means I can do >> >> 32,22323,force >> >> >> >> Or >> >> force,32 >> >> >> >> Or >> >> 32,force >> >> >> > If I use Format: { ,force,,} 32,22323,force can't >> > acceptable. >> > There are three here, if there are out of order, that will >> > cause confuse. >> > Only 32,force,32323 >> > Or 32,,32323,2322 >> > Or ,,323222,3232 >> > Are available. >> >> You need to make sure that all previously valid variants are still usable, > i.e. >> force alone, a number alone, force, and ,force. How >> many variants you want to support with your additions is mostly up to you; >> I'd recommend permitting force in any position. >> > I don't think it's suitable to accept that "force" in any position. > If we defined Format: { ,force,,} > "force" must be located in second position. > And we add comment for each also. > Every position may be defined specifically. As said, with the old format allowing force in either first or second position, you have to at least accept that in the new version too. Accepting force in any position would be a (desirable) courtesy to the user. Jan