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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT 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 8B188C433DB for ; Mon, 1 Mar 2021 11:26:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5AEFB64DF2 for ; Mon, 1 Mar 2021 11:26:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S233196AbhCAL0z (ORCPT ); Mon, 1 Mar 2021 06:26:55 -0500 Received: from foss.arm.com ([217.140.110.172]:55054 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233029AbhCALZh (ORCPT ); Mon, 1 Mar 2021 06:25:37 -0500 Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id BB6701FB; Mon, 1 Mar 2021 03:24:47 -0800 (PST) Received: from p8cg001049571a15.arm.com (unknown [10.163.67.14]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id E0FF23F73C; Mon, 1 Mar 2021 03:24:45 -0800 (PST) From: Anshuman Khandual To: linux-arm-kernel@lists.infradead.org Cc: Anshuman Khandual , Catalin Marinas , Will Deacon , linux-kernel@vger.kernel.org Subject: [PATCH] arm64/mm: Drop THP conditionality from FORCE_MAX_ZONEORDER Date: Mon, 1 Mar 2021 16:55:14 +0530 Message-Id: <1614597914-28565-1-git-send-email-anshuman.khandual@arm.com> X-Mailer: git-send-email 2.7.4 Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently without THP being enabled, MAX_ORDER via FORCE_MAX_ZONEORDER gets reduced to 11, which falls below HUGETLB_PAGE_ORDER for certain 16K and 64K page size configurations. This is problematic which throws up the following warning during boot as pageblock_order via HUGETLB_PAGE_ORDER order exceeds MAX_ORDER. WARNING: CPU: 7 PID: 127 at mm/vmstat.c:1092 __fragmentation_index+0x58/0x70 Modules linked in: CPU: 7 PID: 127 Comm: kswapd0 Not tainted 5.12.0-rc1-00005-g0221e3101a1 #237 Hardware name: linux,dummy-virt (DT) pstate: 20400005 (nzCv daif +PAN -UAO -TCO BTYPE=--) pc : __fragmentation_index+0x58/0x70 lr : fragmentation_index+0x88/0xa8 sp : ffff800016ccfc00 x29: ffff800016ccfc00 x28: 0000000000000000 x27: ffff800011fd4000 x26: 0000000000000002 x25: ffff800016ccfda0 x24: 0000000000000002 x23: 0000000000000640 x22: ffff0005ffcb5b18 x21: 0000000000000002 x20: 000000000000000d x19: ffff0005ffcb3980 x18: 0000000000000004 x17: 0000000000000001 x16: 0000000000000019 x15: ffff800011ca7fb8 x14: 00000000000002b3 x13: 0000000000000000 x12: 00000000000005e0 x11: 0000000000000003 x10: 0000000000000080 x9 : ffff800011c93948 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 0000000000007000 x5 : 0000000000007944 x4 : 0000000000000032 x3 : 000000000000001c x2 : 000000000000000b x1 : ffff800016ccfc10 x0 : 000000000000000d Call trace: __fragmentation_index+0x58/0x70 compaction_suitable+0x58/0x78 wakeup_kcompactd+0x8c/0xd8 balance_pgdat+0x570/0x5d0 kswapd+0x1e0/0x388 kthread+0x154/0x158 ret_from_fork+0x10/0x30 This solves the problem via keeping FORCE_MAX_ZONEORDER unchanged with or without THP on 16K and 64K page size configurations, making sure that the HUGETLB_PAGE_ORDER (and pageblock_order) would never exceed MAX_ORDER. Cc: Catalin Marinas Cc: Will Deacon Cc: linux-arm-kernel@lists.infradead.org Cc: linux-kernel@vger.kernel.org Signed-off-by: Anshuman Khandual --- This applies on v5.12-rc1 and does not seem to have any obvious problem on 16K and 64K page size configurations. This is a simpler alternate to a previous series [1] which tried to solve the very same problem but in a different way. https://patchwork.kernel.org/project/linux-mm/list/?series=431973 arch/arm64/Kconfig | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig index 9cd33c7be429..d4690326274a 100644 --- a/arch/arm64/Kconfig +++ b/arch/arm64/Kconfig @@ -1156,8 +1156,8 @@ config XEN config FORCE_MAX_ZONEORDER int - default "14" if (ARM64_64K_PAGES && TRANSPARENT_HUGEPAGE) - default "12" if (ARM64_16K_PAGES && TRANSPARENT_HUGEPAGE) + default "14" if ARM64_64K_PAGES + default "12" if ARM64_16K_PAGES default "11" help The kernel memory allocator divides physically contiguous memory -- 2.20.1