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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE, SPF_PASS 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 41296C47089 for ; Thu, 27 May 2021 08:05:17 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BAC17613BE for ; Thu, 27 May 2021 08:05:16 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BAC17613BE Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=infradead.org Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 1AA6F6B0036; Thu, 27 May 2021 04:05:16 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 15B476B006E; Thu, 27 May 2021 04:05:16 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id F3DAC8D0001; Thu, 27 May 2021 04:05:15 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0031.hostedemail.com [216.40.44.31]) by kanga.kvack.org (Postfix) with ESMTP id B87AC6B0036 for ; Thu, 27 May 2021 04:05:15 -0400 (EDT) Received: from smtpin13.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay03.hostedemail.com (Postfix) with ESMTP id 4ADB98249980 for ; Thu, 27 May 2021 08:05:15 +0000 (UTC) X-FDA: 78186275790.13.2D762C3 Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf16.hostedemail.com (Postfix) with ESMTP id A989B8019124 for ; Thu, 27 May 2021 08:05:07 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=infradead.org; s=casper.20170209; h=In-Reply-To:Content-Type:MIME-Version: References:Message-ID:Subject:Cc:To:From:Date:Sender:Reply-To: Content-Transfer-Encoding:Content-ID:Content-Description; bh=HZTJtPak0qESqpxtknOeWjbW9dY9rji7MIUgVM4VTb0=; b=mhlRpKNsUp7fwJVYOWwOqzxNZe wX3ay94qV385dgr6it9qVXZErZFu+PTxCzihyL9Y0RsXOt7W+TwzeC+XHMxGZswJjheaTlCxf1pfB ofWnnBj1FsjpHp99A2GTRg6t+f1POAMoUMqhYJrNkYGSgcTHJTwgrWP/ClzVQX1H5FsETL2NZWeZq yJZd1xRRMJyWLSLpY+2q2x+i+3J28B/8PxX+7TMrItNzB9Uvm1d1dz7PukjGMqCppxZ4u021764xH NKtgUbU1RwcIrwbBQUJM+6vZhDryX/edNK342WMHb5OV9lG7R5II65p7XXBl5pVCCeVw7hKBXSaN2 /MtDG6Og==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lmB0C-005JUT-22; Thu, 27 May 2021 08:04:28 +0000 Date: Thu, 27 May 2021 09:04:24 +0100 From: Christoph Hellwig To: Mel Gorman Cc: Andrew Morton , Andrii Nakryiko , Michal Suchanek , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , open list , Arnaldo Carvalho de Melo , Jiri Olsa , Hritik Vijay , bpf , Linux-Net , Linux-MM Subject: Re: [PATCH] mm/page_alloc: Work around a pahole limitation with zero-sized struct pagesets Message-ID: References: <20210526080741.GW30378@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210526080741.GW30378@techsingularity.net> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Authentication-Results: imf16.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=mhlRpKNs; dmarc=none; spf=none (imf16.hostedemail.com: domain of BATV@casper.srs.infradead.org has no SPF policy when checking 90.155.50.34) smtp.mailfrom=BATV@casper.srs.infradead.org X-Stat-Signature: wuegfpbj9wyanpdr4od3kwe6mk1yad4i X-Rspamd-Queue-Id: A989B8019124 X-Rspamd-Server: rspam02 X-HE-Tag: 1622102707-362291 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 Wed, May 26, 2021 at 09:07:41AM +0100, Mel Gorman wrote: > + !defined(CONFIG_DEBUG_LOCK_ALLOC) && \ > + !defined(CONFIG_PAHOLE_HAS_ZEROSIZE_PERCPU_SUPPORT) > + /* > + * pahole 1.21 and earlier gets confused by zero-sized per-CPU > + * variables and produces invalid BTF. Ensure that > + * sizeof(struct pagesets) != 0 for older versions of pahole. > + */ > + char __pahole_hack; > + #warning "pahole too old to support zero-sized struct pagesets" > +#endif Err, hell no. We should not mess up the kernel for broken tools that are not relevant to the kernel build itself ever.