From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-it1-f197.google.com (mail-it1-f197.google.com [209.85.166.197]) by kanga.kvack.org (Postfix) with ESMTP id C9EB16B0637 for ; Thu, 8 Nov 2018 14:13:46 -0500 (EST) Received: by mail-it1-f197.google.com with SMTP id d1-v6so2741402itj.8 for ; Thu, 08 Nov 2018 11:13:46 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id a139-v6sor7975290ita.32.2018.11.08.11.13.45 for (Google Transport Security); Thu, 08 Nov 2018 11:13:45 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <20181107205433.3875-2-logang@deltatee.com> References: <20181107205433.3875-1-logang@deltatee.com> <20181107205433.3875-2-logang@deltatee.com> From: Ard Biesheuvel Date: Thu, 8 Nov 2018 20:13:44 +0100 Message-ID: Subject: Re: [PATCH v2 1/2] mm: Introduce common STRUCT_PAGE_MAX_SHIFT define Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Logan Gunthorpe Cc: Linux Kernel Mailing List , Linux-MM , linux-arch , linux-riscv@lists.infradead.org, linux-arm-kernel , linux-sh@vger.kernel.org, Andrew Morton , Albert Ou , Arnd Bergmann , Catalin Marinas , Palmer Dabbelt , Stephen Bates , Christoph Hellwig On 7 November 2018 at 21:54, Logan Gunthorpe wrote: > This define is used by arm64 to calculate the size of the vmemmap > region. It is defined as the log2 of the upper bound on the size > of a struct page. > > We move it into mm_types.h so it can be defined properly instead of > set and checked with a build bug. This also allows us to use the same > define for riscv. > > Signed-off-by: Logan Gunthorpe > Acked-by: Will Deacon > Acked-by: Andrew Morton > Cc: Catalin Marinas > Cc: Arnd Bergmann > Cc: Christoph Hellwig Acked-by: Ard Biesheuvel > --- > arch/arm64/include/asm/memory.h | 9 --------- > arch/arm64/mm/init.c | 8 -------- > include/asm-generic/fixmap.h | 1 + > include/linux/mm_types.h | 5 +++++ > 4 files changed, 6 insertions(+), 17 deletions(-) > > diff --git a/arch/arm64/include/asm/memory.h b/arch/arm64/include/asm/memory.h > index b96442960aea..f0a5c9531e8b 100644 > --- a/arch/arm64/include/asm/memory.h > +++ b/arch/arm64/include/asm/memory.h > @@ -34,15 +34,6 @@ > */ > #define PCI_IO_SIZE SZ_16M > > -/* > - * Log2 of the upper bound of the size of a struct page. Used for sizing > - * the vmemmap region only, does not affect actual memory footprint. > - * We don't use sizeof(struct page) directly since taking its size here > - * requires its definition to be available at this point in the inclusion > - * chain, and it may not be a power of 2 in the first place. > - */ > -#define STRUCT_PAGE_MAX_SHIFT 6 > - > /* > * VMEMMAP_SIZE - allows the whole linear region to be covered by > * a struct page array > diff --git a/arch/arm64/mm/init.c b/arch/arm64/mm/init.c > index 9d9582cac6c4..1a3e411a1d08 100644 > --- a/arch/arm64/mm/init.c > +++ b/arch/arm64/mm/init.c > @@ -612,14 +612,6 @@ void __init mem_init(void) > BUILD_BUG_ON(TASK_SIZE_32 > TASK_SIZE_64); > #endif > > -#ifdef CONFIG_SPARSEMEM_VMEMMAP > - /* > - * Make sure we chose the upper bound of sizeof(struct page) > - * correctly when sizing the VMEMMAP array. > - */ > - BUILD_BUG_ON(sizeof(struct page) > (1 << STRUCT_PAGE_MAX_SHIFT)); > -#endif > - > if (PAGE_SIZE >= 16384 && get_num_physpages() <= 128) { > extern int sysctl_overcommit_memory; > /* > diff --git a/include/asm-generic/fixmap.h b/include/asm-generic/fixmap.h > index 827e4d3bbc7a..8cc7b09c1bc7 100644 > --- a/include/asm-generic/fixmap.h > +++ b/include/asm-generic/fixmap.h > @@ -16,6 +16,7 @@ > #define __ASM_GENERIC_FIXMAP_H > > #include > +#include > > #define __fix_to_virt(x) (FIXADDR_TOP - ((x) << PAGE_SHIFT)) > #define __virt_to_fix(x) ((FIXADDR_TOP - ((x)&PAGE_MASK)) >> PAGE_SHIFT) > diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h > index 5ed8f6292a53..2c471a2c43fa 100644 > --- a/include/linux/mm_types.h > +++ b/include/linux/mm_types.h > @@ -206,6 +206,11 @@ struct page { > #endif > } _struct_page_alignment; > > +/* > + * Used for sizing the vmemmap region on some architectures > + */ > +#define STRUCT_PAGE_MAX_SHIFT (order_base_2(sizeof(struct page))) > + > #define PAGE_FRAG_CACHE_MAX_SIZE __ALIGN_MASK(32768, ~PAGE_MASK) > #define PAGE_FRAG_CACHE_MAX_ORDER get_order(PAGE_FRAG_CACHE_MAX_SIZE) > > -- > 2.19.0 > > > _______________________________________________ > linux-arm-kernel mailing list > linux-arm-kernel@lists.infradead.org > http://lists.infradead.org/mailman/listinfo/linux-arm-kernel