From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f198.google.com (mail-pf0-f198.google.com [209.85.192.198]) by kanga.kvack.org (Postfix) with ESMTP id 466CB6B0005 for ; Thu, 11 Aug 2016 06:07:37 -0400 (EDT) Received: by mail-pf0-f198.google.com with SMTP id 63so128361017pfx.0 for ; Thu, 11 Aug 2016 03:07:37 -0700 (PDT) Received: from foss.arm.com (foss.arm.com. [217.140.101.70]) by mx.google.com with ESMTP id zy8si2555169pab.68.2016.08.11.03.07.36 for ; Thu, 11 Aug 2016 03:07:36 -0700 (PDT) Date: Thu, 11 Aug 2016 11:07:32 +0100 From: Catalin Marinas Subject: Re: arm64: why set SECTION_SIZE_BITS to 1G size? Message-ID: <20160811100732.GA18366@e104818-lin.cambridge.arm.com> References: <57AC490E.4080204@huawei.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <57AC490E.4080204@huawei.com> Sender: owner-linux-mm@kvack.org List-ID: To: Xishi Qiu Cc: Will Deacon , Linux MM , LKML , chenjie6@huawei.com On Thu, Aug 11, 2016 at 05:44:46PM +0800, Xishi Qiu wrote: > arm64: > SECTION_SIZE_BITS 30 -----1G > > The memory hotplug(add_memory -->check_hotplug_memory_range) > must be aligned with section.So I can not add mem with 64M ... > Can I modify the SECTION_SIZE_BITS to 26? There was a patch to reduce this to 27: http://lkml.kernel.org/g/1465821119-3384-1-git-send-email-jszhang@marvell.com Also some discussions in this thread on a different patch: http://lkml.iu.edu/hypermail/linux/kernel/1604.1/03036.html Does your system really have such small alignment memory blocks? -- Catalin -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org