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From: akpm@linux-foundation.org (Andrew Morton)
To: linux-riscv@lists.infradead.org
Subject: [PATCH 1/2] mm: Introduce common STRUCT_PAGE_MAX_SHIFT define
Date: Wed, 7 Nov 2018 12:11:59 -0800
Message-ID: <20181107121159.b8c9add7c61fb97f48ddd7de@linux-foundation.org> (raw)
In-Reply-To: <20181107173859.24096-2-logang@deltatee.com>

On Wed,  7 Nov 2018 10:38:58 -0700 Logan Gunthorpe <logang@deltatee.com> 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.
> 
> --- 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

Well that was lame.

> --- 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)))

Much better.

Acked-by: Andrew Morton <akpm@linux-foundation.org>

From: Andrew Morton <akpm@linux-foundation.org>
To: Logan Gunthorpe <logang@deltatee.com>
Cc: linux-arch@vger.kernel.org, Albert Ou <aou@eecs.berkeley.edu>,
	Arnd Bergmann <arnd@arndb.de>,
	linux-sh@vger.kernel.org,
	Catalin Marinas <catalin.marinas@arm.com>,
	Palmer Dabbelt <palmer@sifive.com>,
	linux-kernel@vger.kernel.org, Stephen Bates <sbates@raithlin.com>,
	linux-mm@kvack.org, linux-riscv@lists.infradead.org,
	Christoph Hellwig <hch@lst.de>,
	linux-arm-kernel@lists.infradead.org
Subject: Re: [PATCH 1/2] mm: Introduce common STRUCT_PAGE_MAX_SHIFT define
Date: Wed, 7 Nov 2018 12:11:59 -0800
Message-ID: <20181107121159.b8c9add7c61fb97f48ddd7de@linux-foundation.org> (raw)
Message-ID: <20181107201159.8zohJz96Hp3B-ocMHxX3-coLXR3yvdf4fsCgAApHWCs@z> (raw)
In-Reply-To: <20181107173859.24096-2-logang@deltatee.com>

On Wed,  7 Nov 2018 10:38:58 -0700 Logan Gunthorpe <logang@deltatee.com> 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.
> 
> --- 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

Well that was lame.

> --- 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)))

Much better.

Acked-by: Andrew Morton <akpm@linux-foundation.org>

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  parent reply index

Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-11-07 17:38 [PATCH 0/2] Introduce common code for risc-v sparsemem support logang
2018-11-07 17:38 ` Logan Gunthorpe
2018-11-07 17:38 ` [PATCH 1/2] mm: Introduce common STRUCT_PAGE_MAX_SHIFT define logang
2018-11-07 17:38   ` Logan Gunthorpe
2018-11-07 20:11   ` akpm [this message]
2018-11-07 20:11     ` Andrew Morton
2018-11-07 17:38 ` [PATCH 2/2] mm/sparse: add common helper to mark all memblocks present logang
2018-11-07 17:38   ` Logan Gunthorpe
2018-11-07 20:12   ` akpm
2018-11-07 20:12     ` Andrew Morton
2018-11-07 20:19     ` logang
2018-11-07 20:19       ` Logan Gunthorpe
2018-11-07 20:26       ` tglx
2018-11-07 20:26         ` Thomas Gleixner
2018-11-07 20:36         ` logang
2018-11-07 20:36           ` Logan Gunthorpe
2018-11-07 20:38           ` akpm
2018-11-07 20:38             ` Andrew Morton
2018-11-07 20:56             ` tglx
2018-11-07 20:56               ` Thomas Gleixner
2018-12-06 17:40     ` Logan Gunthorpe
2018-12-07 19:56       ` Andrew Morton

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