From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-5.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id E8ACFC43460 for ; Wed, 14 Apr 2021 19:13:39 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BFA1F61220 for ; Wed, 14 Apr 2021 19:13:39 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234819AbhDNTN7 (ORCPT ); Wed, 14 Apr 2021 15:13:59 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]:33405 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234378AbhDNTN5 (ORCPT ); Wed, 14 Apr 2021 15:13:57 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1618427615; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=F6FTiB8UzDW4wKvTNKebl00UCwFSLpS/fkluHFZvJPI=; b=CJ9KdQ82ZM1bxUmVfimmQi5hq5DFa1x2L53ekuk4elu25dAmUyZvN6wsqa+UREI+U0noPO IRw2Fwe/5GVLmGu4jvbHH1vEqgd1z1uq6JcEUQZjR/CgXfZvWB9xvaa7f43F0KXE/LaRyH rgrTXvz26yQQ6DmQEwEUk5200V4e3wo= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-390-dEgJCfFYO6qLSVsI6D4wlQ-1; Wed, 14 Apr 2021 15:13:32 -0400 X-MC-Unique: dEgJCfFYO6qLSVsI6D4wlQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id F38BC6D241; Wed, 14 Apr 2021 19:13:30 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 666961000324; Wed, 14 Apr 2021 19:13:23 +0000 (UTC) Date: Wed, 14 Apr 2021 21:13:22 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Ilias Apalodimas , Matteo Croce , Grygorii Strashko , Arnd Bergmann , Christoph Hellwig , brouer@redhat.com Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210414211322.3799afd4@carbon> In-Reply-To: <20210414115052.GS2531743@casper.infradead.org> References: <20210410205246.507048-1-willy@infradead.org> <20210410205246.507048-2-willy@infradead.org> <20210411114307.5087f958@carbon> <20210411103318.GC2531743@casper.infradead.org> <20210412011532.GG2531743@casper.infradead.org> <20210414101044.19da09df@carbon> <20210414115052.GS2531743@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, 14 Apr 2021 12:50:52 +0100 Matthew Wilcox wrote: > > That said, I think we need to have a quicker fix for the immediate > > issue with 64-bit bit dma_addr on 32-bit arch and the misalignment hole > > it leaves[3] in struct page. In[3] you mention ppc32, does it only > > happens on certain 32-bit archs? =20 >=20 > AFAICT it happens on mips32, ppc32, arm32 and arc. It doesn't happen > on x86-32 because dma_addr_t is 32-bit aligned. (If others want to reproduce). First I could not reproduce on ARM32. Then I found out that enabling CONFIG_XEN on ARCH=3Darm was needed to cause the issue by enabling CONFIG_ARCH_DMA_ADDR_T_64BIT. Details below signature. --=20 Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer =46rom file: arch/arm/Kconfig config XEN bool "Xen guest support on ARM" depends on ARM && AEABI && OF depends on CPU_V7 && !CPU_V6 depends on !GENERIC_ATOMIC64 depends on MMU select ARCH_DMA_ADDR_T_64BIT select ARM_PSCI select SWIOTLB select SWIOTLB_XEN select PARAVIRT help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. My make compile command: export VERSION=3Dgcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/ export CROSS_COMPILE=3D"/home/${USER}/cross-compilers/${VERSION}/bin/arm-n= one-linux-gnueabihf-" make -j8 ARCH=3Darm CROSS_COMPILE=3D$CROSS_COMPILE Pahole output: $ pahole -C page mm/page_alloc.o struct page { long unsigned int flags; /* 0 4 */ /* XXX 4 bytes hole, try to pack */ union { struct { struct list_head lru; /* 8 8 */ struct address_space * mapping; /* 16 4 */ long unsigned int index; /* 20 4 */ long unsigned int private; /* 24 4 */ }; /* 8 20 */ struct { dma_addr_t dma_addr; /* 8 8 */ }; /* 8 8 */ struct { union { struct list_head slab_list; /* 8 8 = */ struct { struct page * next; /* 8 4 = */ short int pages; /* 12 2 */ short int pobjects; /* 14 2 = */ }; /* 8 8 */ }; /* 8 8 */ struct kmem_cache * slab_cache; /* 16 4 */ void * freelist; /* 20 4 */ union { void * s_mem; /* 24 4 */ long unsigned int counters; /* 24 4 = */ struct { unsigned int inuse:16; /* 24: 0 = 4 */ unsigned int objects:15; /* 24:1= 6 4 */ unsigned int frozen:1; /* 24:31 = 4 */ }; /* 24 4 */ }; /* 24 4 */ }; /* 8 20 */ struct { long unsigned int compound_head; /* 8 4 */ unsigned char compound_dtor; /* 12 1 */ unsigned char compound_order; /* 13 1 */ /* XXX 2 bytes hole, try to pack */ atomic_t compound_mapcount; /* 16 4 */ unsigned int compound_nr; /* 20 4 */ }; /* 8 16 */ struct { long unsigned int _compound_pad_1; /* 8 4 */ atomic_t hpage_pinned_refcount; /* 12 4 */ struct list_head deferred_list; /* 16 8 */ }; /* 8 16 */ struct { long unsigned int _pt_pad_1; /* 8 4 */ pgtable_t pmd_huge_pte; /* 12 4 */ long unsigned int _pt_pad_2; /* 16 4 */ union { struct mm_struct * pt_mm; /* 20 4 */ atomic_t pt_frag_refcount; /* 20 4 */ }; /* 20 4 */ spinlock_t ptl; /* 24 4 */ }; /* 8 20 */ struct { struct dev_pagemap * pgmap; /* 8 4 */ void * zone_device_data; /* 12 4 */ }; /* 8 8 */ struct callback_head callback_head __attribute__((__aligned= __(4))); /* 8 8 */ } __attribute__((__aligned__(8))); /* 8 24 */ union { atomic_t _mapcount; /* 32 4 */ unsigned int page_type; /* 32 4 */ unsigned int active; /* 32 4 */ int units; /* 32 4 */ }; /* 32 4 */ atomic_t _refcount; /* 36 4 */ /* size: 40, cachelines: 1, members: 4 */ /* sum members: 36, holes: 1, sum holes: 4 */ /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 08587C433B4 for ; Wed, 14 Apr 2021 19:15:33 +0000 (UTC) Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 604E26121E for ; 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Wed, 14 Apr 2021 19:13:30 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 666961000324; Wed, 14 Apr 2021 19:13:23 +0000 (UTC) Date: Wed, 14 Apr 2021 21:13:22 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210414211322.3799afd4@carbon> In-Reply-To: <20210414115052.GS2531743@casper.infradead.org> References: <20210410205246.507048-1-willy@infradead.org> <20210410205246.507048-2-willy@infradead.org> <20210411114307.5087f958@carbon> <20210411103318.GC2531743@casper.infradead.org> <20210412011532.GG2531743@casper.infradead.org> <20210414101044.19da09df@carbon> <20210414115052.GS2531743@casper.infradead.org> MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Arnd Bergmann , Grygorii Strashko , netdev@vger.kernel.org, Ilias Apalodimas , linux-mips@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mm@kvack.org, brouer@redhat.com, Matteo Croce , linuxppc-dev@lists.ozlabs.org, Christoph Hellwig , linux-arm-kernel@lists.infradead.org Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Wed, 14 Apr 2021 12:50:52 +0100 Matthew Wilcox wrote: > > That said, I think we need to have a quicker fix for the immediate > > issue with 64-bit bit dma_addr on 32-bit arch and the misalignment hole > > it leaves[3] in struct page. In[3] you mention ppc32, does it only > > happens on certain 32-bit archs? =20 >=20 > AFAICT it happens on mips32, ppc32, arm32 and arc. It doesn't happen > on x86-32 because dma_addr_t is 32-bit aligned. (If others want to reproduce). First I could not reproduce on ARM32. Then I found out that enabling CONFIG_XEN on ARCH=3Darm was needed to cause the issue by enabling CONFIG_ARCH_DMA_ADDR_T_64BIT. Details below signature. --=20 Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer =46rom file: arch/arm/Kconfig config XEN bool "Xen guest support on ARM" depends on ARM && AEABI && OF depends on CPU_V7 && !CPU_V6 depends on !GENERIC_ATOMIC64 depends on MMU select ARCH_DMA_ADDR_T_64BIT select ARM_PSCI select SWIOTLB select SWIOTLB_XEN select PARAVIRT help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. My make compile command: export VERSION=3Dgcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/ export CROSS_COMPILE=3D"/home/${USER}/cross-compilers/${VERSION}/bin/arm-n= one-linux-gnueabihf-" make -j8 ARCH=3Darm CROSS_COMPILE=3D$CROSS_COMPILE Pahole output: $ pahole -C page mm/page_alloc.o struct page { long unsigned int flags; /* 0 4 */ /* XXX 4 bytes hole, try to pack */ union { struct { struct list_head lru; /* 8 8 */ struct address_space * mapping; /* 16 4 */ long unsigned int index; /* 20 4 */ long unsigned int private; /* 24 4 */ }; /* 8 20 */ struct { dma_addr_t dma_addr; /* 8 8 */ }; /* 8 8 */ struct { union { struct list_head slab_list; /* 8 8 = */ struct { struct page * next; /* 8 4 = */ short int pages; /* 12 2 */ short int pobjects; /* 14 2 = */ }; /* 8 8 */ }; /* 8 8 */ struct kmem_cache * slab_cache; /* 16 4 */ void * freelist; /* 20 4 */ union { void * s_mem; /* 24 4 */ long unsigned int counters; /* 24 4 = */ struct { unsigned int inuse:16; /* 24: 0 = 4 */ unsigned int objects:15; /* 24:1= 6 4 */ unsigned int frozen:1; /* 24:31 = 4 */ }; /* 24 4 */ }; /* 24 4 */ }; /* 8 20 */ struct { long unsigned int compound_head; /* 8 4 */ unsigned char compound_dtor; /* 12 1 */ unsigned char compound_order; /* 13 1 */ /* XXX 2 bytes hole, try to pack */ atomic_t compound_mapcount; /* 16 4 */ unsigned int compound_nr; /* 20 4 */ }; /* 8 16 */ struct { long unsigned int _compound_pad_1; /* 8 4 */ atomic_t hpage_pinned_refcount; /* 12 4 */ struct list_head deferred_list; /* 16 8 */ }; /* 8 16 */ struct { long unsigned int _pt_pad_1; /* 8 4 */ pgtable_t pmd_huge_pte; /* 12 4 */ long unsigned int _pt_pad_2; /* 16 4 */ union { struct mm_struct * pt_mm; /* 20 4 */ atomic_t pt_frag_refcount; /* 20 4 */ }; /* 20 4 */ spinlock_t ptl; /* 24 4 */ }; /* 8 20 */ struct { struct dev_pagemap * pgmap; /* 8 4 */ void * zone_device_data; /* 12 4 */ }; /* 8 8 */ struct callback_head callback_head __attribute__((__aligned= __(4))); /* 8 8 */ } __attribute__((__aligned__(8))); /* 8 24 */ union { atomic_t _mapcount; /* 32 4 */ unsigned int page_type; /* 32 4 */ unsigned int active; /* 32 4 */ int units; /* 32 4 */ }; /* 32 4 */ atomic_t _refcount; /* 36 4 */ /* size: 40, cachelines: 1, members: 4 */ /* sum members: 36, holes: 1, sum holes: 4 */ /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-3.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI, SPF_HELO_NONE,SPF_PASS autolearn=no autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 262BBC433ED for ; Wed, 14 Apr 2021 19:15:49 +0000 (UTC) Received: from desiato.infradead.org (desiato.infradead.org [90.155.92.199]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 87FF061220 for ; 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Wed, 14 Apr 2021 19:13:30 +0000 (UTC) Received: from carbon (unknown [10.36.110.19]) by smtp.corp.redhat.com (Postfix) with ESMTP id 666961000324; Wed, 14 Apr 2021 19:13:23 +0000 (UTC) Date: Wed, 14 Apr 2021 21:13:22 +0200 From: Jesper Dangaard Brouer To: Matthew Wilcox Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, netdev@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, linux-arm-kernel@lists.infradead.org, linux-mips@vger.kernel.org, Ilias Apalodimas , Matteo Croce , Grygorii Strashko , Arnd Bergmann , Christoph Hellwig , brouer@redhat.com Subject: Re: [PATCH 1/1] mm: Fix struct page layout on 32-bit systems Message-ID: <20210414211322.3799afd4@carbon> In-Reply-To: <20210414115052.GS2531743@casper.infradead.org> References: <20210410205246.507048-1-willy@infradead.org> <20210410205246.507048-2-willy@infradead.org> <20210411114307.5087f958@carbon> <20210411103318.GC2531743@casper.infradead.org> <20210412011532.GG2531743@casper.infradead.org> <20210414101044.19da09df@carbon> <20210414115052.GS2531743@casper.infradead.org> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210414_121337_264239_22A53E55 X-CRM114-Status: GOOD ( 18.35 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Wed, 14 Apr 2021 12:50:52 +0100 Matthew Wilcox wrote: > > That said, I think we need to have a quicker fix for the immediate > > issue with 64-bit bit dma_addr on 32-bit arch and the misalignment hole > > it leaves[3] in struct page. In[3] you mention ppc32, does it only > > happens on certain 32-bit archs? > > AFAICT it happens on mips32, ppc32, arm32 and arc. It doesn't happen > on x86-32 because dma_addr_t is 32-bit aligned. (If others want to reproduce). First I could not reproduce on ARM32. Then I found out that enabling CONFIG_XEN on ARCH=arm was needed to cause the issue by enabling CONFIG_ARCH_DMA_ADDR_T_64BIT. Details below signature. -- Best regards, Jesper Dangaard Brouer MSc.CS, Principal Kernel Engineer at Red Hat LinkedIn: http://www.linkedin.com/in/brouer >From file: arch/arm/Kconfig config XEN bool "Xen guest support on ARM" depends on ARM && AEABI && OF depends on CPU_V7 && !CPU_V6 depends on !GENERIC_ATOMIC64 depends on MMU select ARCH_DMA_ADDR_T_64BIT select ARM_PSCI select SWIOTLB select SWIOTLB_XEN select PARAVIRT help Say Y if you want to run Linux in a Virtual Machine on Xen on ARM. My make compile command: export VERSION=gcc-arm-10.2-2020.11-x86_64-arm-none-linux-gnueabihf/ export CROSS_COMPILE="/home/${USER}/cross-compilers/${VERSION}/bin/arm-none-linux-gnueabihf-" make -j8 ARCH=arm CROSS_COMPILE=$CROSS_COMPILE Pahole output: $ pahole -C page mm/page_alloc.o struct page { long unsigned int flags; /* 0 4 */ /* XXX 4 bytes hole, try to pack */ union { struct { struct list_head lru; /* 8 8 */ struct address_space * mapping; /* 16 4 */ long unsigned int index; /* 20 4 */ long unsigned int private; /* 24 4 */ }; /* 8 20 */ struct { dma_addr_t dma_addr; /* 8 8 */ }; /* 8 8 */ struct { union { struct list_head slab_list; /* 8 8 */ struct { struct page * next; /* 8 4 */ short int pages; /* 12 2 */ short int pobjects; /* 14 2 */ }; /* 8 8 */ }; /* 8 8 */ struct kmem_cache * slab_cache; /* 16 4 */ void * freelist; /* 20 4 */ union { void * s_mem; /* 24 4 */ long unsigned int counters; /* 24 4 */ struct { unsigned int inuse:16; /* 24: 0 4 */ unsigned int objects:15; /* 24:16 4 */ unsigned int frozen:1; /* 24:31 4 */ }; /* 24 4 */ }; /* 24 4 */ }; /* 8 20 */ struct { long unsigned int compound_head; /* 8 4 */ unsigned char compound_dtor; /* 12 1 */ unsigned char compound_order; /* 13 1 */ /* XXX 2 bytes hole, try to pack */ atomic_t compound_mapcount; /* 16 4 */ unsigned int compound_nr; /* 20 4 */ }; /* 8 16 */ struct { long unsigned int _compound_pad_1; /* 8 4 */ atomic_t hpage_pinned_refcount; /* 12 4 */ struct list_head deferred_list; /* 16 8 */ }; /* 8 16 */ struct { long unsigned int _pt_pad_1; /* 8 4 */ pgtable_t pmd_huge_pte; /* 12 4 */ long unsigned int _pt_pad_2; /* 16 4 */ union { struct mm_struct * pt_mm; /* 20 4 */ atomic_t pt_frag_refcount; /* 20 4 */ }; /* 20 4 */ spinlock_t ptl; /* 24 4 */ }; /* 8 20 */ struct { struct dev_pagemap * pgmap; /* 8 4 */ void * zone_device_data; /* 12 4 */ }; /* 8 8 */ struct callback_head callback_head __attribute__((__aligned__(4))); /* 8 8 */ } __attribute__((__aligned__(8))); /* 8 24 */ union { atomic_t _mapcount; /* 32 4 */ unsigned int page_type; /* 32 4 */ unsigned int active; /* 32 4 */ int units; /* 32 4 */ }; /* 32 4 */ atomic_t _refcount; /* 36 4 */ /* size: 40, cachelines: 1, members: 4 */ /* sum members: 36, holes: 1, sum holes: 4 */ /* forced alignments: 1, forced holes: 1, sum forced holes: 4 */ /* last cacheline: 40 bytes */ } __attribute__((__aligned__(8))); _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel