[Top] [All Lists]

Re: [PATCH V2 4/8] MIPS: Add NUMA support for Loongson-3

To: Ralf Baechle <>
Subject: Re: [PATCH V2 4/8] MIPS: Add NUMA support for Loongson-3
From: David Daney <>
Date: Wed, 04 Jun 2014 10:22:17 -0700
Cc: Huacai Chen <>, John Crispin <>, "Steven J. Hill" <>, Aurelien Jarno <>,, Fuxin Zhang <>, Zhangjin Wu <>
Dkim-signature: v=1; a=rsa-sha256; c=relaxed/relaxed;; s=20120113; h=message-id:date:from:user-agent:mime-version:to:cc:subject :references:in-reply-to:content-type:content-transfer-encoding; bh=gwIy/zP3LhbH+XHkPBggKDnb03hCsLlAPZ1gR+Xmqgk=; b=GwDog7aLmGxCvMHgPuivnxFAhqWFhTpdmiXZYh+tm/BKorgnGnQgke1spVbvkUKbM4 VfBqWrXULByaHpOJBg6oJTip3nCoX3aLTCDzvfcag6rA3WoHNV42GxmzmPQJ6DXyfRnW Ngwp8kP5Q6XesqLTeIIfMp7C8bcqGWFzPwVWwBGyIi8GdW+Qz2tHf0uR/ZkKMjxnVA3G SLf9tYxvIBVkEMolwaHv1T8Sf2JWnu3CQ+N9CWOr9rOgNfSg+VbTgi50J3AQG6AIo+aJ XCSYjez/+kJaIEj5N1K1WYs6LSIQopjw/hOHzx24kIxZES+QpUuQQ+GygWVo1JCI3csb DCGQ==
In-reply-to: <>
List-archive: <>
List-help: <>
List-id: linux-mips <>
List-owner: <>
List-post: <>
List-software: Ecartis version 1.0.0
List-subscribe: <>
List-unsubscribe: <>
Original-recipient: rfc822;
References: <> <> <> <> <>
User-agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130625 Thunderbird/17.0.7
On 06/03/2014 11:46 PM, Ralf Baechle wrote:

A more important value which I haven't noticed the Looongson patches to
modify is SECTION_SIZE_BITS in <asm/sparsemem.h>:

# define SECTION_SIZE_BITS      29
# define SECTION_SIZE_BITS      28

Don't ask me why its definition depends on MIPS_HUGE_TLB_SUPPORT and
PAGE_SIZE_64KB - the value describes the larges chunk of contiguous
memory (that is for example memory per node) and that doesn't depend
on these CONFIG_* symbols.

I think I can answer that.  We do the same thing for OCTEON I think.

IIRC, with SPARSEMEM, you cannot allocate high order pages that span multiple sections. Therefore you have to have the sections be at least as large as a huge page. in the case of CONFIG_PAGE_SIZE_64KB, the huge pages are 512MB which doesn't fit in 28 bits.



<Prev in Thread] Current Thread [Next in Thread>