From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751047AbcFXG6L (ORCPT ); Fri, 24 Jun 2016 02:58:11 -0400 Received: from mailout2.samsung.com ([203.254.224.25]:50799 "EHLO mailout2.samsung.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750853AbcFXG6J (ORCPT ); Fri, 24 Jun 2016 02:58:09 -0400 X-AuditID: cbfee68e-f79266d000001428-0c-576cd9fdaf89 Date: Fri, 24 Jun 2016 06:58:05 +0000 (GMT) From: Manjeet Pawar Subject: Re: Re: [PATCH] arm:swiotlb:keep disabled in default configuration To: Stefano Stabellini , "konrad@darnok.org" Cc: PANKAJ MISHRA , AJEET YADAV , Rohit Thapliyal , "linux-arm-kernel@lists.infradead.org" , "linux-kernel@vger.kernel.org" , "linux@arm.linux.org.uk" Reply-to: manjeet.p@samsung.com MIME-version: 1.0 X-MTR: 20160624045531022@manjeet.p Msgkey: 20160624045531022@manjeet.p X-EPLocale: en_US.windows-1252 X-Priority: 3 X-EPWebmail-Msg-Type: personal X-EPWebmail-Reply-Demand: 0 X-EPApproval-Locale: X-EPHeader: ML X-MLAttribute: X-RootMTR: 20160624045531022@manjeet.p X-ParentMTR: X-ArchiveUser: X-CPGSPASS: N X-ConfirmMail: N,general Content-type: text/plain; charset=windows-1252 MIME-version: 1.0 Message-id: <762265370.17291466751484096.JavaMail.weblogic@epmlwas08b> X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFprMKsWRmVeSWpSXmKPExsWyRsSkVvfvzZxwg/+bDS0u75rD5sDo8XmT XABjlIhNSmpOZllqkb4dgpUgkvFi1x7WgldCFbfPLWFpYFwh1MXIySEkoCIxpeUIaxcjB4eE gIlE3zw+kLCEgJjEhXvr2boYuYBKljJKbJjUzQyRMJE49OkXI0RiDqPE3qO7GEGaWQRUJf4t TAUx2QR0JJ5+ARsvLOAtcWXXbTaQsIhAjMSaaQYgncwCx5kkLn88yg5xgrxE/8qLYON5BQQl Ts58wgKxSkliwb6HLBBxZYkDd/8zQcTlJJZMvQxl80rMaH/KAhOf9nUN1JnSEudnbWCE+WXx 98dQcX6JY7d3QPUKSEw9c5AR4nV1iQPzuCHCfBJrFr5lgSnfdWo5M8yq+1vmQrVKSGxtecIK YjMLKEpM6X7IDmEbSBxZNIcV3Su8Am4Sm98eZgf5XULgDIfE75UrGScwKs1CUjcLyaxZSGYh q1nAyLKKUTS1ILmgOCm9yEivODG3uDQvXS85P3cTIzBRnP73rG8H480D1ocY1TkYpURL84qT E/PyEpNyUuNzE3PS8otyU1OUeHh/FOSEC7EmlhVX5h5iNAXG3URmKdHkfGDyyiuJNzQ2M7Iw NTE1NjK3NFMS502Q+hksJJCeWJKanZpakFoUX1Sak1p8iJGJg1OqgdHhx8H/+ZvOtO3bsXbp gn2ea26f9YlZO0v30TeZaXWM4YE/+789/fPrxos3NbEiC55aOyh8/qEg6ZVgc+nL97NCyQZT dO/O689fIN9REa99U/VP/05tlnyl1GNZkScXHOzb9mH5o3ThbhFJqWfvi0K+rFpscoB7YXiF Y7nJzarfu65JKR1Zb3BBiaU4I9FQi7moOBEAbQxP4CYDAAA= X-Brightmail-Tracker: H4sIAAAAAAAAA+NgFvrIKsWRmVeSWpSXmKPExsVy+t/tPt2/N3PCDZZf1rK4vGsOmwOjx+dN cgGMUQU2Kak5mWWpRfp2NhmpiSmpRQqpecn5KZl56bZK3sHxzvGmZgaGuoaWFuZKCnmJuam2 Si4+AbpumTlA45UUyhJzSoFCAYnFxUpAE4ryS0tSFTLyi0tslaINzY30jAz0TI30DE1jrQwN DIxMgWoSCjJe7NrDWvBKqOL2uSUsDYwrhLoYOTmEBFQkprQcYQWxJQRMJA59+sUIYYtJXLi3 nq2LkQuoZg6jxN6ju4ASHBwsAqoS/xamgphsAjoST7+AjREW8Ja4sus2G0hYRCBGYs00A5BO ZoHjTBKXPx5lh1glL9G/8iIziM0rIChxcuYTFohVShIL9j1kgYgrSxy4+58JIi4nsWTqZSib V2JG+1MWmPi0r2uYIWxpifOzNsCdvPj7Y6g4v8Sx2zugegUkpp45CHa9hIC6xIF53BBhPok1 C9+ywJTvOrWcGWbV/S1zoVolJLa2PAGHDrOAosSU7ofsELaBxJFFc1jRvcIr4Cax+e1h9gmM srOQpGYhaZ+FpB1ZzQJGllWMoqkFyQXFSekVJnrFibnFpXnpesn5uZsYwWnp2ZIdjA0XrA8x qnMwSomW5hUnJ+blJSblpMbnJuak5RflpqYo8fBOEM0JF2JNLCuuzD3EqAK06tGG1RcYpVjy 8vNSlUR4718BSvOmJFZWpRblxxeV5qQWH2I0BcbqRGYp0eR8YOLNK4k3NDYxNzU2tTAwNDc3 UxLnDfi7LkxIID2xJDU7NbUgtQimj4mDU6qB8RZnb7qtI8/fxWmnYyfmP25PUwtOjJoX7r3V cDWL/bYT2tH/RNmKGVL86l4tPGeWmrHv0R/9q/mzHs57N1f4ivDj8tZqZl3ZazP+uuxqvbj7 gXq5fmB7cLybo4HkA4lpfyPtKiLZVZawLGl7pfiZzWP21y3Won7qn6zKzv27mrLk5KT7aawb lViKMxINtZiLihMByS8dNIQDAAA= DLP-Filter: Pass X-CFilter-Loop: Reflected Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id u5O6wGPB023384 > > On Jun 23, 2016 8:27 AM, "Manjeet Pawar" wrote: >> > >> > From: Rohit Thapliyal >> > >> > swiotlb implementation not required to be enabled in arm and >> > disabling it reduces uImage size by 16KB. >> > >> >> How so? There are no DMA operations on ARM? >Xen actively uses the swiotlb on ARM, see >arch/arm64/include/asm/dma-mapping.h:get_dma_ops >arch/arm/xen/mm.c:xen_swiotlb_dma_ops If XEN is enabled, it shall eventually enable SWIOTLB through SWIOTLB_XEN. So, there is no need to keep it enabled otherwise. ------- Original Message ------- Sender : Stefano Stabellini Date : Jun 24, 2016 01:00 (GMT+09:00) Title : Re: [PATCH] arm:swiotlb:keep disabled in default configuration On Thu, 23 Jun 2016, Stefano Stabellini wrote: > On Jun 23, 2016 8:27 AM, "Manjeet Pawar" wrote: > > > > From: Rohit Thapliyal > > > > swiotlb implementation not required to be enabled in arm and > > disabling it reduces uImage size by 16KB. > > > > How so? There are no DMA operations on ARM? Xen actively uses the swiotlb on ARM, see arch/arm64/include/asm/dma-mapping.h:get_dma_ops arch/arm/xen/mm.c:xen_swiotlb_dma_ops > > Signed-off-by: Rohit Thapliyal > > Signed-off-by: Ajeet Kumar Yadav > > --- > > arch/arm/Kconfig | 2 +- > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > diff --git a/arch/arm/Kconfig b/arch/arm/Kconfig > > index 90542db..ae65f29 100644 > > --- a/arch/arm/Kconfig > > +++ b/arch/arm/Kconfig > > @@ -1754,7 +1754,7 @@ config SECCOMP > > defined by each seccomp mode. > > > > config SWIOTLB > > - def_bool y > > + def_bool n > > > > config IOMMU_HELPER > > def_bool SWIOTLB > > -- > > 1.7.9.5 > > >