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=-9.7 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 758EAC4363A for ; Tue, 20 Oct 2020 18:09:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0CDC42098B for ; Tue, 20 Oct 2020 18:09:43 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2437306AbgJTSJn convert rfc822-to-8bit (ORCPT ); Tue, 20 Oct 2020 14:09:43 -0400 Received: from foss.arm.com ([217.140.110.172]:54862 "EHLO foss.arm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2388059AbgJTSJm (ORCPT ); Tue, 20 Oct 2020 14:09:42 -0400 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 E179231B; Tue, 20 Oct 2020 11:09:41 -0700 (PDT) Received: from e113632-lin (e113632-lin.cambridge.arm.com [10.1.194.46]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPSA id 1FE8F3F719; Tue, 20 Oct 2020 11:09:41 -0700 (PDT) References: <20201020173409.1266576-1-vanshikonda@os.amperecomputing.com> User-agent: mu4e 0.9.17; emacs 26.3 From: Valentin Schneider To: Vanshidhar Konda Cc: linux-arm-kernel@lists.infradead.org, patches@amperecomputing.com, linux-kernel@vger.kernel.org, Anshuman.Khandual@arm.com Subject: Re: [PATCH] arm64: NUMA: Kconfig: Increase max number of nodes In-reply-to: <20201020173409.1266576-1-vanshikonda@os.amperecomputing.com> Date: Tue, 20 Oct 2020 19:09:36 +0100 Message-ID: MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: 8BIT Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Nit on the subject: this only increases the default, the max is still 2¹⁰. On 20/10/20 18:34, Vanshidhar Konda wrote: > The current arm64 max NUMA nodes default to 4. Today's arm64 systems can > reach or exceed 16. Increase the number to 64 (matching x86_64). > > Signed-off-by: Vanshidhar Konda > --- > arch/arm64/Kconfig | 2 +- > 1 file changed, 1 insertion(+), 1 deletion(-) > > diff --git a/arch/arm64/Kconfig b/arch/arm64/Kconfig > index 893130ce1626..3e69d3c981be 100644 > --- a/arch/arm64/Kconfig > +++ b/arch/arm64/Kconfig > @@ -980,7 +980,7 @@ config NUMA > config NODES_SHIFT > int "Maximum NUMA Nodes (as a power of 2)" > range 1 10 > - default "2" > + default "6" This leads to more statically allocated memory for things like node to CPU maps (see uses of MAX_NUMNODES), but that shouldn't be too much of an issue. AIUI this also directly correlates to how many more page->flags bits are required: are we sure the max 10 works on any aarch64 platform? I'm genuinely asking here, given that I'm mostly a stranger to the mm world. The default should be something we're somewhat confident works everywhere. > depends on NEED_MULTIPLE_NODES > help > Specify the maximum number of NUMA Nodes available on the target