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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 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 8301AC47087 for ; Fri, 28 May 2021 09:04:26 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 3250D6127A for ; Fri, 28 May 2021 09:04:26 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3250D6127A Authentication-Results: mail.kernel.org; dmarc=none (p=none dis=none) header.from=techsingularity.net Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id C2AF06B006C; Fri, 28 May 2021 05:04:25 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C01666B006E; Fri, 28 May 2021 05:04:25 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id AA1B86B0071; Fri, 28 May 2021 05:04:25 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0062.hostedemail.com [216.40.44.62]) by kanga.kvack.org (Postfix) with ESMTP id 79BAC6B006C for ; Fri, 28 May 2021 05:04:25 -0400 (EDT) Received: from smtpin12.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 2805A81DC for ; Fri, 28 May 2021 09:04:25 +0000 (UTC) X-FDA: 78190053690.12.4B1A4A6 Received: from outbound-smtp62.blacknight.com (outbound-smtp62.blacknight.com [46.22.136.251]) by imf13.hostedemail.com (Postfix) with ESMTP id 0C656E000255 for ; Fri, 28 May 2021 09:04:15 +0000 (UTC) Received: from mail.blacknight.com (pemlinmail03.blacknight.ie [81.17.254.16]) by outbound-smtp62.blacknight.com (Postfix) with ESMTPS id 0F55FFA780 for ; Fri, 28 May 2021 10:04:23 +0100 (IST) Received: (qmail 29895 invoked from network); 28 May 2021 09:04:22 -0000 Received: from unknown (HELO techsingularity.net) (mgorman@techsingularity.net@[84.203.23.168]) by 81.17.254.9 with ESMTPSA (AES256-SHA encrypted, authenticated); 28 May 2021 09:04:22 -0000 Date: Fri, 28 May 2021 10:04:21 +0100 From: Mel Gorman To: David Laight Cc: 'Andrii Nakryiko' , Christoph Hellwig , Andrew Morton , Arnaldo Carvalho de Melo , 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: <20210528090421.GK30378@techsingularity.net> References: <20210526080741.GW30378@techsingularity.net> <20210527090422.GA30378@techsingularity.net> <8fe547e9e87f40aebce82021d76a2d08@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-15 Content-Disposition: inline In-Reply-To: <8fe547e9e87f40aebce82021d76a2d08@AcuMS.aculab.com> User-Agent: Mutt/1.10.1 (2018-07-13) Authentication-Results: imf13.hostedemail.com; dkim=none; dmarc=none; spf=pass (imf13.hostedemail.com: domain of mgorman@techsingularity.net designates 46.22.136.251 as permitted sender) smtp.mailfrom=mgorman@techsingularity.net X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: 0C656E000255 X-Stat-Signature: 11e4setbnndju1416jsmfn1w98ziyjon X-HE-Tag: 1622192655-838630 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, May 28, 2021 at 08:09:39AM +0000, David Laight wrote: > From: Andrii Nakryiko > > Sent: 27 May 2021 15:42 > ... > > I agree that empty structs are useful, but here we are talking about > > per-CPU variables only, which is the first use case so far, as far as > > I can see. If we had pahole 1.22 released and widely packaged it could > > have been a viable option to force it on everyone. > ... > > Would it be feasible to put the sources for pahole into the > kernel repository and build it at the same time as objtool? > We don't store other build dependencies like compilers, binutils etc in the kernel repository even though minimum versions are mandated. Obviously tools/ exists but for the most part, they are tools that do not exist in other repositories and are kernel-specific. I don't know if pahole would be accepted and it introduces the possibility that upstream pahole and the kernel fork of it would diverge. -- Mel Gorman SUSE Labs