Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751790AbbBKIkI (ORCPT ); Wed, 11 Feb 2015 03:40:08 -0500 Received: from mga01.intel.com ([192.55.52.88]:12904 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750923AbbBKIkF convert rfc822-to-8bit (ORCPT ); Wed, 11 Feb 2015 03:40:05 -0500 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.09,557,1418112000"; d="scan'208";a="684101911" From: "Wang, Xiaoming" To: David Vrabel , Konrad Rzeszutek Wilk CC: "linux-mips@linux-mips.org" , "pebolle@tiscali.nl" , "Zhang, Dongxing" , "lauraa@codeaurora.org" , "d.kasatkin@samsung.com" , "heiko.carstens@de.ibm.com" , "linux-kernel@vger.kernel.org" , "ralf@linux-mips.org" , "chris@chris-wilson.co.uk" , "takahiro.akashi@linaro.org" , "linux@horizon.com" , "xen-devel@lists.xenproject.org" , "boris.ostrovsky@oracle.com" , "Liu, Chuansheng" , "akpm@linux-foundation.org" Subject: RE: [Xen-devel] [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize configurable as flexible requirement about SW-IOMMU. Thread-Topic: [Xen-devel] [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize configurable as flexible requirement about SW-IOMMU. Thread-Index: AQHQQRJJKhpis9DUDUadJ41Llkm2a5zh7MKAgADSw2CABmUHgIACAXdQ Date: Wed, 11 Feb 2015 08:38:29 +0000 Message-ID: References: <1423177274-22118-1-git-send-email-xiaoming.wang@intel.com> <20150205193241.GC11646@x230.dumpdata.com> <54D9D363.5060904@citrix.com> In-Reply-To: <54D9D363.5060904@citrix.com> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 8BIT MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 2654 Lines: 64 Dear David > -----Original Message----- > From: David Vrabel [mailto:david.vrabel@citrix.com] > Sent: Tuesday, February 10, 2015 5:46 PM > To: Wang, Xiaoming; Konrad Rzeszutek Wilk > Cc: linux-mips@linux-mips.org; pebolle@tiscali.nl; Zhang, Dongxing; > lauraa@codeaurora.org; d.kasatkin@samsung.com; > heiko.carstens@de.ibm.com; linux-kernel@vger.kernel.org; ralf@linux- > mips.org; chris@chris-wilson.co.uk; takahiro.akashi@linaro.org; > david.vrabel@citrix.com; linux@horizon.com; xen- > devel@lists.xenproject.org; boris.ostrovsky@oracle.com; Liu, Chuansheng; > akpm@linux-foundation.org > Subject: Re: [Xen-devel] [PATCH] modify the IO_TLB_SEGSIZE to > io_tlb_segsize configurable as flexible requirement about SW-IOMMU. > > On 06/02/15 00:10, Wang, Xiaoming wrote: > > > > > >> -----Original Message----- > >> From: Konrad Rzeszutek Wilk [mailto:konrad.wilk@oracle.com] > >> Sent: Friday, February 6, 2015 3:33 AM > >> To: Wang, Xiaoming > >> Cc: ralf@linux-mips.org; boris.ostrovsky@oracle.com; > >> david.vrabel@citrix.com; linux-mips@linux-mips.org; linux- > >> kernel@vger.kernel.org; xen-devel@lists.xenproject.org; akpm@linux- > >> foundation.org; linux@horizon.com; lauraa@codeaurora.org; > >> heiko.carstens@de.ibm.com; d.kasatkin@samsung.com; > >> takahiro.akashi@linaro.org; chris@chris-wilson.co.uk; > >> pebolle@tiscali.nl; Liu, Chuansheng; Zhang, Dongxing > >> Subject: Re: [PATCH] modify the IO_TLB_SEGSIZE to io_tlb_segsize > >> configurable as flexible requirement about SW-IOMMU. > >> > >> On Fri, Feb 06, 2015 at 07:01:14AM +0800, xiaomin1 wrote: > >>> The maximum of SW-IOMMU is limited to 2^11*128 = 256K. > >>> While in different platform and different requirements this seems > improper. > >>> So modify the IO_TLB_SEGSIZE to io_tlb_segsize as configurable is > >>> make > >> sense. > >> > >> More details please. What is the issue you are hitting? > >> > > Example: > > If 1M bytes are requied. There has an error like. > > Instead of allowing the bouncing of such large buffers, could the gadget > driver be modified to submit the buffers to the hardware in smaller chunks? > > David Our target is try to make IO_TLB_SEGSIZE configurable. Neither 256 bytes or 1M bytes seems suitable value, I think. It's better to use the tactics something like kmem_cache_create in kmalloc function. But SW-IOMMU seems more lighter. So we choose variable rather than function. Xiaoming. -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/