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 290F4C4707F for ; Thu, 27 May 2021 09:19:52 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id C7E7D6105A for ; Thu, 27 May 2021 09:19:51 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org C7E7D6105A 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 BA6126B0036; Thu, 27 May 2021 05:19:50 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id B49F76B006E; Thu, 27 May 2021 05:19:50 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 7053B6B0070; Thu, 27 May 2021 05:19:50 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0178.hostedemail.com [216.40.44.178]) by kanga.kvack.org (Postfix) with ESMTP id 2CAD16B0036 for ; Thu, 27 May 2021 05:19:50 -0400 (EDT) Received: from smtpin36.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay01.hostedemail.com (Postfix) with ESMTP id A7C6D180ACEF3 for ; Thu, 27 May 2021 09:19:49 +0000 (UTC) X-FDA: 78186463698.36.364354D Received: from casper.infradead.org (casper.infradead.org [90.155.50.34]) by imf30.hostedemail.com (Postfix) with ESMTP id 36051E000806 for ; Thu, 27 May 2021 09:19:43 +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=iRsknJTfFiEDd9n74h43kOIWLR9thmAzm1ZrB74a5Xk=; b=Mt+PC76TyiEwy+b6L48ycifDAR XKE8hldzILOrEh24nLs1DSsELIQas2IMv96tixj0ygC3f1Lv3VEvRBeKiKDdtAWb19AjM5LU/k5h/ x3XDVHdV417fF1H3Ioq5EQ/NwRnCfBr+Fc1RIrEBzMubdx7Ex60adikqLp3aVUdx7YpCkeCFVn2k6 gyVeE5GIlQjhhQX6EMJnfTUpNzx1SHu06QnzDFpnSeKq7kiP0aebbIVgqScJDxi7FexSCpNSXgBHN 1vL261F7MmvNoS69Ac4LUN+xB6UnMqaSfWnV3cPlTxon563qfBxvhw3p6iNh2RBqXL5IZxp9HvQB8 7v4DbJ5Q==; Received: from hch by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lmC9l-005NI5-1e; Thu, 27 May 2021 09:18:41 +0000 Date: Thu, 27 May 2021 10:18:21 +0100 From: Christoph Hellwig To: Mel Gorman Cc: Christoph Hellwig , Andrew Morton , Arnaldo Carvalho de Melo , Andrii Nakryiko , Michal Suchanek , Alexei Starovoitov , Daniel Borkmann , Martin KaFai Lau , Song Liu , Yonghong Song , John Fastabend , KP Singh , open list , 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> <20210527090422.GA30378@techsingularity.net> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210527090422.GA30378@techsingularity.net> X-SRS-Rewrite: SMTP reverse-path rewritten from by casper.infradead.org. See http://www.infradead.org/rpr.html Authentication-Results: imf30.hostedemail.com; dkim=pass header.d=infradead.org header.s=casper.20170209 header.b=Mt+PC76T; spf=none (imf30.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; dmarc=none X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 36051E000806 X-Stat-Signature: pi8x9fhn4zo7a41aoq47a6xym5ysd83i X-HE-Tag: 1622107183-49021 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 Thu, May 27, 2021 at 10:04:22AM +0100, Mel Gorman wrote: > What do you suggest as an alternative? > > I added Arnaldo to the cc as he tagged the last released version of > pahole (1.21) and may be able to tag a 1.22 with Andrii's fix for pahole > included. > > The most obvious alternative fix for this issue is to require pahole > 1.22 to set CONFIG_DEBUG_INFO_BTF but obviously a version 1.22 that works > needs to exist first and right now it does not. I'd be ok with this but > users of DEBUG_INFO_BTF may object given that it'll be impossible to set > the option until there is a release. Yes, disable BTF. Empty structs are a very useful feature that we use in various places in the kernel. We can't just keep piling hacks over hacks to make that work with a recent fringe feature.