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=-16.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER, INCLUDES_PATCH,MAILING_LIST_MULTI,NICE_REPLY_A,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 E2B0DC433DB for ; Fri, 26 Feb 2021 20:37:21 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 4C19364EFA for ; Fri, 26 Feb 2021 20:37:20 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4C19364EFA Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=linux-foundation.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id BA0CD8D0002; Fri, 26 Feb 2021 15:37:19 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id B51CB6B0083; Fri, 26 Feb 2021 15:37:19 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id A917C8D0002; Fri, 26 Feb 2021 15:37:19 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0237.hostedemail.com [216.40.44.237]) by kanga.kvack.org (Postfix) with ESMTP id 927826B0082 for ; Fri, 26 Feb 2021 15:37:19 -0500 (EST) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay05.hostedemail.com (Postfix) with ESMTP id 4EDD4181AF5CC for ; Fri, 26 Feb 2021 20:37:19 +0000 (UTC) X-FDA: 77861578998.13.8B032CD Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by imf19.hostedemail.com (Postfix) with ESMTP id 61B9290009EB for ; Fri, 26 Feb 2021 20:37:14 +0000 (UTC) Received: by mail.kernel.org (Postfix) with ESMTPSA id 5521E64F03; Fri, 26 Feb 2021 20:37:17 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1614371837; bh=Ly0f27B7LvWPQIY/noxzHUfAiBR7+fZJjZHCqygyerw=; h=Date:From:To:Cc:Subject:In-Reply-To:References:From; b=zJhisgXnLiT9g94dR6TY00koT/Ql+rflRrpcB41mBSqMhYtj/D6Yx166tD0LQTGmp qlINLn7lfkO6b+9EncYHBQ+FTqGI6/MOMpYyC76WwLDirIBX32wST/4Dz+JkrSKAHo WmM/b4uUHPf7DrEkKbDAoqnnT6lrzQZEjJ7aCOPI= Date: Fri, 26 Feb 2021 12:37:16 -0800 From: Andrew Morton To: Palmer Dabbelt Cc: atishp@atishpatra.org, peterz@infradead.org, srikar@linux.vnet.ibm.com, valentin.schneider@arm.com, vbabka@suse.cz, mpe@ellerman.id.au, Palmer Dabbelt , linux-kernel@vger.kernel.org, linux-mm@kvack.org, kernel-team@android.com, "Kirill A. Shutemov" Subject: Re: [PATCH 1/2] mm: Guard a use of node_reclaim_distance with CONFIFG_NUMA Message-Id: <20210226123716.6bc2a463e0ee9d1770c7966b@linux-foundation.org> In-Reply-To: <20210226201721.510177-1-palmer@dabbelt.com> References: <20210226201721.510177-1-palmer@dabbelt.com> X-Mailer: Sylpheed 3.5.1 (GTK+ 2.24.31; x86_64-pc-linux-gnu) Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Stat-Signature: s6ftoa98ia78y37a6nock61eewxycnwz X-Rspamd-Server: rspam02 X-Rspamd-Queue-Id: 61B9290009EB Received-SPF: none (linux-foundation.org>: No applicable sender policy available) receiver=imf19; identity=mailfrom; envelope-from=""; helo=mail.kernel.org; client-ip=198.145.29.99 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614371834-155967 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: On Fri, 26 Feb 2021 12:17:20 -0800 Palmer Dabbelt wrote: > From: Palmer Dabbelt > > This is only useful under CONFIG_NUMA. IIUC skipping the check is the > right thing to do here, as without CONFIG_NUMA there will never be any > large node distances on non-NUMA systems. > > I expected this to manifest as a link failure under (!CONFIG_NUMA && > CONFIG_TRANSPARENT_HUGE_PAGES), but I'm not actually seeing that. I > think the reference is just getting pruned before it's checked, but I > didn't get that from reading the code so I'm worried I'm missing > something. > > Either way, this is necessary to guard the definition of > node_reclaim_distance with CONFIG_NUMA. > > Signed-off-by: Palmer Dabbelt > --- > mm/khugepaged.c | 2 ++ > 1 file changed, 2 insertions(+) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index a7d6cb912b05..b1bf191c3a54 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -819,8 +819,10 @@ static bool khugepaged_scan_abort(int nid) > for (i = 0; i < MAX_NUMNODES; i++) { > if (!khugepaged_node_load[i]) > continue; > +#ifdef CONFIG_NUMA > if (node_distance(nid, i) > node_reclaim_distance) > return true; > +#endif > } > return false; > } This makes the entire loop a no-op. Perhaps Kirill can help take a look at removing unnecessary code in khugepaged.c when CONFIG_NUMA=n?