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=-6.4 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MSGID_FROM_MTA_HEADER,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED autolearn=no 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 C2DECC4338F for ; Fri, 6 Aug 2021 15:23:50 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3048061163 for ; Fri, 6 Aug 2021 15:23:49 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org 3048061163 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=nvidia.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=kvack.org Received: by kanga.kvack.org (Postfix) id 5E66A8D0001; Fri, 6 Aug 2021 11:23:49 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 5962B6B0071; Fri, 6 Aug 2021 11:23:49 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 40FF88D0001; Fri, 6 Aug 2021 11:23:49 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0057.hostedemail.com [216.40.44.57]) by kanga.kvack.org (Postfix) with ESMTP id 232CC6B006C for ; Fri, 6 Aug 2021 11:23:49 -0400 (EDT) Received: from smtpin33.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id B566C1E09D for ; Fri, 6 Aug 2021 15:23:48 +0000 (UTC) X-FDA: 78445025736.33.4D334BE Received: from NAM10-MW2-obe.outbound.protection.outlook.com (mail-mw2nam10on2043.outbound.protection.outlook.com [40.107.94.43]) by imf05.hostedemail.com (Postfix) with ESMTP id E8E5B5022E12 for ; Fri, 6 Aug 2021 15:23:47 +0000 (UTC) ARC-Seal: i=1; a=rsa-sha256; s=arcselector9901; d=microsoft.com; cv=none; b=Ls2ISwAjsc3w7WMpmTal1EY8XGWWy6dpxOJxS+o3etiMdTYPeeZCBM7FvoUG9TmiXrQdTQikeD9nc5lqTJ8XEQmo48SSmeGs4XhGwsN11y9ghxen9iV/ZTLC0Mn6m1dK699pElR61lYP5P6QEXs3LD2QQ0eM9TCiVr6qPPdYihWF3TS4c5NC0Mj6x/g3j05IyoJMYlLJs0wh/jYjp0/nj4qyktocpi3mwKBYQXc90wDeqjv318OXMsCUCiehdVROKVgU4QKFwWJO1G1UJUw7cks6evvsB/EaRXQJ/oQFicUZvEAwGgz9js4Bq0wrVLzpgrqfrwT6RmuzgliMRLa4CQ== ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=microsoft.com; s=arcselector9901; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=FbQD1nQ/J2DLSnDc0q16Qd03KhjscbrD+uTNrSKm0LQ=; b=Qutb24a8Fc1OKFoiGztVcAiEJtP81naLw5yyXgmZL/cmBjji5GJ6LXcdlj2O/Qc9i0nF8kUzohaTqimzdQKBbNfjLFk5QNa01Yiwm+HmeEaDNHXnx2xQ2dOYerh1G2C30QwYo7TJ6Z3XAoVbnTfJYhsaE+eTKgKtML00OzNfPnGWmTp0GHgMglaGPSbH4mPZ9FZtaVMxSTnvSVvkvutG8k6vKTiOtxhBcOUoyep2WQCRCjcsCgGAmefjgkvil4Wy5Frtt99wCmnP+D8Iz0VrNg1XQWnFcknNtYW+EkOkA0gjnmCpu3uEksWlD7AsNvhjAgz+H3i444GKvK6aSX2GOA== ARC-Authentication-Results: i=1; mx.microsoft.com 1; spf=pass smtp.mailfrom=nvidia.com; dmarc=pass action=none header.from=nvidia.com; dkim=pass header.d=nvidia.com; arc=none DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=Nvidia.com; s=selector2; h=From:Date:Subject:Message-ID:Content-Type:MIME-Version:X-MS-Exchange-SenderADCheck; bh=FbQD1nQ/J2DLSnDc0q16Qd03KhjscbrD+uTNrSKm0LQ=; b=lDj3dMXK5E+Mxha4LZ8UW82AFQxNH+bvhP4QV0HsA4v+ieWoJ0vXpnP1XtDCSLoCtPSWiUOkYNdfRxkli4957V17zfumwFJRQEo7yYDVMQX3K1xClFdZhQ28mqymDulkkRF6umNdYHnkW4Zzql9navIgRb0d+82fkUa/UIE/FNgR7eqlzMXBFPULadzRil/4lqSSNuZ9Y8/GieF1+jKw//H+QS1XZptziGzd8pyA4oFOTSxiAUN6m1msegoyEiLdMIqjvLTBppFxoDr8u5FUeCA3jA2IoffXri83qfL5F8bFG+X7A04tlXObtDXSLEpZOsKl6sBV51MiXREIlKwRNA== Received: from MN2PR12MB3823.namprd12.prod.outlook.com (2603:10b6:208:168::26) by MN2PR12MB4029.namprd12.prod.outlook.com (2603:10b6:208:167::27) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.4394.17; Fri, 6 Aug 2021 15:23:45 +0000 Received: from MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::dcee:535c:30e:95f4]) by MN2PR12MB3823.namprd12.prod.outlook.com ([fe80::dcee:535c:30e:95f4%6]) with mapi id 15.20.4394.017; Fri, 6 Aug 2021 15:23:45 +0000 From: Zi Yan To: Vlastimil Babka Cc: David Hildenbrand , linux-mm@kvack.org, Matthew Wilcox , "Kirill A . Shutemov" , Mike Kravetz , Michal Hocko , John Hubbard , linux-kernel@vger.kernel.org, Kees Cook , Peter Zijlstra , Nicholas Piggin , Thomas Gleixner Subject: Re: [RFC PATCH 12/15] mm: Make MAX_ORDER of buddy allocator configurable via Kconfig SET_MAX_ORDER. 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dkim=pass header.d=Nvidia.com header.s=selector2 header.b=lDj3dMXK; dmarc=pass (policy=quarantine) header.from=nvidia.com; spf=none (imf05.hostedemail.com: domain of ziy@nvidia.com has no SPF policy when checking 40.107.94.43) smtp.mailfrom=ziy@nvidia.com X-Stat-Signature: uoa3jkproyie5g9y79to1gy6fasr3jdt X-Rspamd-Queue-Id: E8E5B5022E12 X-Rspamd-Server: rspam01 X-HE-Tag: 1628263427-582118 X-Bogosity: Ham, tests=bogofilter, spamicity=0.000000, version=1.2.4 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: --=_MailMate_FCE8FC84-793E-4C3F-ACC8-A4481287DCF4_= Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable On 6 Aug 2021, at 11:16, Vlastimil Babka wrote: > On 8/5/21 9:02 PM, Zi Yan wrote: >> From: Zi Yan >> +config SET_MAX_ORDER >> + int "Set maximum order of buddy allocator" >> + depends on SPARSEMEM_VMEMMAP && (ARCH_FORCE_MAX_ORDER =3D 0) >> + range 11 255 >> + default "11" >> + help >> + The kernel memory allocator divides physically contiguous memory >> + blocks into "zones", where each zone is a power of two number of >> + pages. This option selects the largest power of two that the kern= el >> + keeps in the memory allocator. If you need to allocate very large= >> + blocks of physically contiguous memory, then you may need to >> + increase this value. >> + >> + This config option is actually maximum order plus one. For example= , >> + a value of 11 means that the largest free memory block is 2^10 pag= es. > > It's enough that it's confusing for the devs, we could spare the users = and add > +1 to the value they specify :) Sure. I will change the existing ARCH_FORCE_MAX_ORDER too, otherwise peop= le might get confused by two different MAX_ORDERs. Since this Kconfig only appears= when ARCH_FORCE_MAX_ORDER is not specified. =E2=80=94 Best Regards, Yan, Zi --=_MailMate_FCE8FC84-793E-4C3F-ACC8-A4481287DCF4_= Content-Description: OpenPGP digital signature Content-Disposition: attachment; filename="signature.asc" Content-Type: application/pgp-signature; name="signature.asc" -----BEGIN PGP SIGNATURE----- iQJDBAEBCgAtFiEEh7yFAW3gwjwQ4C9anbJR82th+ooFAmENU/wPHHppeUBudmlk aWEuY29tAAoJEJ2yUfNrYfqKsvwQALYfaYlLHQxPltzWBSjHmEZXSHiiDwEso1Za tXQ2qT85VKLgOGeZa4vFei9AYjk628OqUDjZFaF4iz9cGsnLMT/kEkQ/2+h6nJ4C O/mmHkEvCkgKwST54A82d4I19WUl9XvliFbtUre/DCVNlug60temutQi4TLYyFxy jipDaRaTngXRdxWs5U9EebdGYxzWjTLEv2qRKqT3Ut+U3TE//n5otUQCZUiCV0NI 5KCmkqfGawGDsl6J8O2ZKRP0J6mh5oEPxot3Qh+Spi0EmDLOPWJ83PugZulMz3Ni KZXnAlrsiBAZ79af3KsBDHyqSiAfJ9Xc7Wvf23HRzWn6cscuBgQTJ8Wq/JY38Jsl RHn/zxONFo37Qm6XwEnaSFvuvIEBgPqjtinixr/6pla4UIwb9G60cF4OBlpaMcnT +2bf0tsLPRnyChlQqPTVYG1Pu+hYTAZtRp9xH1idsm5ixdFrRIy5Rk85xq7ZmPjj yIg+gz9C/Lmz0plSoRfsZ5eRNC/FxctZhAKv6RxVuZXoHxXLYpIlyQw1PDEZH6ca G3iuJiBfVnl+7GyCF84zFo5TAWL/HzjXOYY1NWtH7xEn3RE3PvhP/hBlRIKBNZrZ cpzuUfEhLdwcT9ZEUsCm8vYTQAg9BkepCp4aN7MYB/BPPSvj1FuFNyOZS/I6CkS/ Nr6/mH4j =qbJx -----END PGP SIGNATURE----- --=_MailMate_FCE8FC84-793E-4C3F-ACC8-A4481287DCF4_=--