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=-13.8 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=unavailable 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 7B5E4C433FE for ; Mon, 7 Dec 2020 01:42:19 +0000 (UTC) Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134]) (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 2DDC8229C4 for ; Mon, 7 Dec 2020 01:42:19 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 2DDC8229C4 Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=hisilicon.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding: Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive: List-Unsubscribe:List-Id:MIME-Version:In-Reply-To:References:Message-ID:Date: Subject:To:From:Reply-To:Content-ID:Content-Description:Resent-Date: Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner; bh=M8OMM0tCPiNrdSk0oS6Zs3umE8P4jR4eqwCGHQyGaaY=; b=3fA5EAnceIlX6LYBstGsd3bIN MY3XYeXVNvyAnOSU9AZeML3RRpc32fKuFovYk/snnT2QvF8MOSM52WfJpZjwkp+fIuXftZPokLpl9 vrZWIxWr/bbkjOpT3STJB5GvA+Kyo1McbEoGk/e7FGdLThGFq+ykMKOFYqGzBuQPxK8Ev197eoSsE D30DFtKmNbxU6uMvuC1LAXJUSf9JgFq5Jr/BiTPA6/IbeIJaqsjk6cWimM0lsVWZsuv0oRRFSEeEB d+014AEAlTi5mCTLdQ1FFI4BNty7vTYC4jOFHpShNZlQrYNSSEfZ9iTc162fHVIMluDD0MaQQpB9U atkTWCwpQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1km5WK-00008o-2v; Mon, 07 Dec 2020 01:40:56 +0000 Received: from szxga01-in.huawei.com ([45.249.212.187]) by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux)) id 1km5WF-0008PS-MT for linux-arm-kernel@lists.infradead.org; Mon, 07 Dec 2020 01:40:53 +0000 Received: from DGGEMM402-HUB.china.huawei.com (unknown [172.30.72.55]) by szxga01-in.huawei.com (SkyGuard) with ESMTP id 4Cq5b44yPYzVgTc; Mon, 7 Dec 2020 09:39:44 +0800 (CST) Received: from dggemm753-chm.china.huawei.com (10.1.198.59) by DGGEMM402-HUB.china.huawei.com (10.3.20.210) with Microsoft SMTP Server (TLS) id 14.3.487.0; Mon, 7 Dec 2020 09:40:35 +0800 Received: from dggemi761-chm.china.huawei.com (10.1.198.147) by dggemm753-chm.china.huawei.com (10.1.198.59) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256) id 15.1.1913.5; Mon, 7 Dec 2020 09:40:35 +0800 Received: from dggemi761-chm.china.huawei.com ([10.9.49.202]) by dggemi761-chm.china.huawei.com ([10.9.49.202]) with mapi id 15.01.1913.007; Mon, 7 Dec 2020 09:40:35 +0800 From: "Song Bao Hua (Barry Song)" To: Mike Rapoport , Will Deacon Subject: RE: [PATCH] arm64: mm: decrease the section size to reduce the memory reserved for the page map Thread-Topic: [PATCH] arm64: mm: decrease the section size to reduce the memory reserved for the page map Thread-Index: AQHWyd8Pm9rJc08RmUuZbQcVlySHKKnmQzeAgAAIcQCABJBfwA== Date: Mon, 7 Dec 2020 01:40:35 +0000 Message-ID: <60cb36d5dfcb4f9c904a83b520ecfe84@hisilicon.com> References: <20201204014443.43329-1-liwei213@huawei.com> <20201204111347.GA844@willie-the-truck> <20201204114400.GT123287@linux.ibm.com> In-Reply-To: <20201204114400.GT123287@linux.ibm.com> Accept-Language: en-GB, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.126.201.26] MIME-Version: 1.0 X-CFilter-Loop: Reflected X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20201206_204052_292073_CFFEB718 X-CRM114-Status: GOOD ( 23.20 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: "steve.capper@arm.com" , "catalin.marinas@arm.com" , "linux-kernel@vger.kernel.org" , "nsaenzjulienne@suse.de" , "liwei \(CM\)" , butao , "linux-arm-kernel@lists.infradead.org" , fengbaopeng 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 > -----Original Message----- > From: Mike Rapoport [mailto:rppt@linux.ibm.com] > Sent: Saturday, December 5, 2020 12:44 AM > To: Will Deacon > Cc: liwei (CM) ; catalin.marinas@arm.com; fengbaopeng > ; nsaenzjulienne@suse.de; steve.capper@arm.com; > Song Bao Hua (Barry Song) ; > linux-arm-kernel@lists.infradead.org; linux-kernel@vger.kernel.org; butao > > Subject: Re: [PATCH] arm64: mm: decrease the section size to reduce the memory > reserved for the page map > > On Fri, Dec 04, 2020 at 11:13:47AM +0000, Will Deacon wrote: > > On Fri, Dec 04, 2020 at 09:44:43AM +0800, Wei Li wrote: > > > For the memory hole, sparse memory model that define SPARSEMEM_VMEMMAP > > > do not free the reserved memory for the page map, decrease the section > > > size can reduce the waste of reserved memory. > > > > > > Signed-off-by: Wei Li > > > Signed-off-by: Baopeng Feng > > > Signed-off-by: Xia Qing > > > --- > > > arch/arm64/include/asm/sparsemem.h | 2 +- > > > 1 file changed, 1 insertion(+), 1 deletion(-) > > > > > > diff --git a/arch/arm64/include/asm/sparsemem.h > b/arch/arm64/include/asm/sparsemem.h > > > index 1f43fcc79738..8963bd3def28 100644 > > > --- a/arch/arm64/include/asm/sparsemem.h > > > +++ b/arch/arm64/include/asm/sparsemem.h > > > @@ -7,7 +7,7 @@ > > > > > > #ifdef CONFIG_SPARSEMEM > > > #define MAX_PHYSMEM_BITS CONFIG_ARM64_PA_BITS > > > -#define SECTION_SIZE_BITS 30 > > > +#define SECTION_SIZE_BITS 27 > > > > We chose '30' to avoid running out of bits in the page flags. What changed? > > I think that for 64-bit there are still plenty of free bits. I didn't > check now, but when I played with SPARSEMEM on m68k there were 8 bits > for section out of 32. > > > With this patch, I can trigger: > > > > ./include/linux/mmzone.h:1170:2: error: Allocator MAX_ORDER exceeds > SECTION_SIZE > > #error Allocator MAX_ORDER exceeds SECTION_SIZE > > > > if I bump up NR_CPUS and NODES_SHIFT. > > I don't think it's related to NR_CPUS and NODES_SHIFT. > This seems rather 64K pages that cause this. > > Not that is shouldn't be addressed. Right now, only 4K PAGES will define ARM64_SWAPPER_USES_SECTION_MAPS. Other cases will use vmemmap_populate_basepages(). The original patch should be only addressing the issue in 4K pages: https://lore.kernel.org/lkml/20200812010655.96339-1-liwei213@huawei.com/ would we do something like the below? #ifdef CONFIG_ARM64_4K_PAGE #define SECTION_SIZE_BITS 27 #else #define SECTION_SIZE_BITS 30 #endif > > > Will > > -- > Sincerely yours, > Mike. Thanks Barry _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel