Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S966572AbaFTUU0 (ORCPT ); Fri, 20 Jun 2014 16:20:26 -0400 Received: from aserp1040.oracle.com ([141.146.126.69]:42010 "EHLO aserp1040.oracle.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751731AbaFTUUY (ORCPT ); Fri, 20 Jun 2014 16:20:24 -0400 Date: Fri, 20 Jun 2014 16:20:17 -0400 From: Konrad Rzeszutek Wilk To: Jungseok Lee Cc: linux-kernel@vger.kernel.org, sungjinn.chung@samsung.com, "'linux-samsung-soc'" Subject: Re: [PATCH] swiotlb: Correct kernel command line handler Message-ID: <20140620202017.GB5558@laptop.dumpdata.com> References: <011801cf4d4c$f7ba51f0$e72ef5d0$@samsung.com> <20140401124606.GA7135@phenom.dumpdata.com> <004c01cf4e2d$1d84a1c0$588de540$@samsung.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <004c01cf4e2d$1d84a1c0$588de540$@samsung.com> User-Agent: Mutt/1.5.23 (2014-03-12) X-Source-IP: acsinet21.oracle.com [141.146.126.237] Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Apr 02, 2014 at 01:36:29PM +0900, Jungseok Lee wrote: > On Tuesday, April 01, 2014 9:46 PM, Konrad Rzeszutek Wilk wrote: > > On Tue, Apr 01, 2014 at 10:51:58AM +0900, Jungseok Lee wrote: > > > This patch corrects kernel command line handler when io_tlb_nslabs is > > > set to 0. > > > > > > A current implementation allocates default size memory (64MB) when > > > 0 is given to io_tlb_nslabs ("swiotlb=0") by kernel command line. > > > In other words, memory is allocated unintentionally. > > > > What are the other IOMMUs that end up taking over the DMA ops? > > I think that no other IOMMUs take over it on ARM64 system, except Xen. > > > Or do you end up with no DMA ops? > > I focus on ARM64 system which uses swiotlb as default DMA ops. > > If some ARM64 platforms would like to use memory only from > __get_free_pages in swiotlb_alloc_coherent function, an > interface would be needed to configure reserved memory size. > > Thus, I add it to kernel command line handler. OK. I somehow have lost track of this patch. Is this patch still valid? > > Best Regards > Jungseok Lee > > > > > > > Signed-off-by: Jungseok Lee > > > Signed-off-by: Sungjinn Chung > > > --- > > > lib/swiotlb.c | 8 ++++++-- > > > 1 file changed, 6 insertions(+), 2 deletions(-) > > > > > > diff --git a/lib/swiotlb.c b/lib/swiotlb.c index b604b83..9fe9f71 > > > 100644 > > > --- a/lib/swiotlb.c > > > +++ b/lib/swiotlb.c > > > @@ -55,6 +55,8 @@ > > > > > > int swiotlb_force; > > > > > > +static int swiotlb_no_use; > > > + > > > /* > > > * Used to do a quick range check in swiotlb_tbl_unmap_single and > > > * swiotlb_tbl_sync_single_*, to see if the memory was in fact > > > allocated by this @@ -102,6 +104,8 @@ setup_io_tlb_npages(char *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 (!io_tlb_nslabs) > > > + swiotlb_no_use = 1; > > > } > > > if (*str == ',') > > > ++str; > > > @@ -212,7 +216,7 @@ swiotlb_init(int verbose) > > > unsigned char *vstart; > > > unsigned long bytes; > > > > > > - if (!io_tlb_nslabs) { > > > + if (!swiotlb_no_use && !io_tlb_nslabs) { > > > io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); > > > io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > > > } > > > @@ -244,7 +248,7 @@ swiotlb_late_init_with_default_size(size_t default_size) > > > unsigned int order; > > > int rc = 0; > > > > > > - if (!io_tlb_nslabs) { > > > + if (!swiotlb_no_use && !io_tlb_nslabs) { > > > io_tlb_nslabs = (default_size >> IO_TLB_SHIFT); > > > io_tlb_nslabs = ALIGN(io_tlb_nslabs, IO_TLB_SEGSIZE); > > > } > > > -- > > > 1.7.10.4 > > > > > > > > -- > > To unsubscribe from this list: send the line "unsubscribe linux-samsung-soc" in the body of a message > > to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html > -- 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/