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=-15.3 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_SANE_1 autolearn=ham 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 BD6E0C433E9 for ; Mon, 1 Mar 2021 15:18:59 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 96C2564E42 for ; Mon, 1 Mar 2021 15:18:59 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237121AbhCAPSk (ORCPT ); Mon, 1 Mar 2021 10:18:40 -0500 Received: from mail.kernel.org ([198.145.29.99]:40900 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237030AbhCAPST (ORCPT ); Mon, 1 Mar 2021 10:18:19 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id E672D600CC; Mon, 1 Mar 2021 15:18:02 +0000 (UTC) Date: Mon, 1 Mar 2021 15:18:00 +0000 From: Catalin Marinas To: Anshuman Khandual Cc: linux-arm-kernel@lists.infradead.org, Will Deacon , linux-kernel@vger.kernel.org, Steve Capper Subject: Re: [PATCH] arm64/mm: Drop THP conditionality from FORCE_MAX_ZONEORDER Message-ID: <20210301151759.GC3250@arm.com> References: <1614597914-28565-1-git-send-email-anshuman.khandual@arm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <1614597914-28565-1-git-send-email-anshuman.khandual@arm.com> User-Agent: Mutt/1.10.1 (2018-07-13) Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Mar 01, 2021 at 04:55:14PM +0530, Anshuman Khandual wrote: > 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 I think this makes sense. The original "14" was added by Steve C in commit d03bb1455f3a ("ARM64: mm: Raise MAX_ORDER for 64KB pages and THP.") back in 3.11. It looks like hugetlbfs (and the HUGETLB_PAGE_ORDER definition) was added in the same kernel but we somehow missed the !TRANSPARENT_HUGEPAGE case and smaller page order. The warning in __fragmentation_index() was added much later in 4.14. Anyway, the patch looks fine to me, we could apply it to some past stable kernels: Acked-by: Catalin Marinas An alternative would have be to add a dependency on both TRANSPARENT_HUGEPAGE and HUGETLB_PAGE but I'm not sure it's worth it. -- Catalin