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=-2.7 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED 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 A0523C47089 for ; Thu, 27 May 2021 14:37:37 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 46FBB613D8 for ; Thu, 27 May 2021 14:37:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 46FBB613D8 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=gmail.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 668FB6B006E; Thu, 27 May 2021 10:37:36 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 612616B0070; Thu, 27 May 2021 10:37:36 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 1AA1E6B0071; Thu, 27 May 2021 10:37:36 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0116.hostedemail.com [216.40.44.116]) by kanga.kvack.org (Postfix) with ESMTP id CB05B6B006E for ; Thu, 27 May 2021 10:37:35 -0400 (EDT) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 6468E4857 for ; Thu, 27 May 2021 14:37:35 +0000 (UTC) X-FDA: 78187264470.28.6D40883 Received: from mail-yb1-f175.google.com (mail-yb1-f175.google.com [209.85.219.175]) by imf29.hostedemail.com (Postfix) with ESMTP id BA5272D4 for ; Thu, 27 May 2021 14:37:24 +0000 (UTC) Received: by mail-yb1-f175.google.com with SMTP id z38so987189ybh.5 for ; Thu, 27 May 2021 07:37:34 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=mime-version:references:in-reply-to:from:date:message-id:subject:to :cc; bh=HRnF4kAS3qhXpOKU/S5e/EyDvZ8VJSiLJYQXCB3/Htw=; b=XNffNLozWKxhduxFmbqbzLGjdrxdvvI+Ap0UkIe1KEJ1/tPLDUz6/Wxpl+VYiE82hB tBGq37HnDzHIZg2XNJ/FR+uKaCshHcyXU40xQSjEe9oRgpNbjxU0zhq3pmqrYR2qveWL 4soK6Y+FoW9KQqFaMWZIND95qM+akKPWekrJgoozuDlWRRkGiYdxECS7FaDzKRI2ytax /2V8LbuQ+/c0GLNu8DcIkxnAc3iQuU71vlniIAwY2ly87GF0GN8jFxN/mlaygnZkOF56 e0fEmvY7MQ0gz+b6VEsMPGynntb0Yzo73CZ/l9PLP4357JiApwS91S5fF1K7FYG8EHtY oYAg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:mime-version:references:in-reply-to:from:date :message-id:subject:to:cc; bh=HRnF4kAS3qhXpOKU/S5e/EyDvZ8VJSiLJYQXCB3/Htw=; b=RpmQVsSzyqfh9biIbNtELmK6r2hTspSJ7YIMWHnD9OCPbTWZC14ET4TLy+r8T/lG84 KHwEi6VZW+lewUROrWSmoQLTRD/iaUOg9ksePsFMeYnGPMiwyuToWazEGc13JCm7S3Ci f3mQjEah7wVHA96OJVTQ4TXWqdV+Sf/65vczS+UpvJpmAFzZITH8dWSoJBIyQdXODnS8 yfO7VJoTcxYw+mGQtjSQdLzIZ3qmJGu4+CXduG/GKw85I8f0K4N6zBCM0FGPB5zuRgOE VKAgSzgdrMUq2zId8mDxvWo2W5ywwN8C8M+KNUPJRSVpQNO/YwbNVzXS7mRRwpJ9A9Ej XYeA== X-Gm-Message-State: AOAM5327XHYekYufqMWt9JU6EOjldzNrvgYCrSaYufxD2a3EtLB5/xd8 173tvEDyRBFHFm99rNs+xrHotfJ6Z3dZJpHqbww= X-Google-Smtp-Source: ABdhPJxmgH1A3+I50+c5X37BMXbr/rnqwS7h/1bj7Un87/hBdSe+jucE/s3XZuuOjc5PO2/sW6LnyzzFmyePJDDgkYk= X-Received: by 2002:a5b:f05:: with SMTP id x5mr5170003ybr.425.1622126254450; Thu, 27 May 2021 07:37:34 -0700 (PDT) MIME-Version: 1.0 References: <20210526080741.GW30378@techsingularity.net> <20210527090422.GA30378@techsingularity.net> In-Reply-To: From: Andrii Nakryiko Date: Thu, 27 May 2021 07:37:23 -0700 Message-ID: Subject: Re: [PATCH] mm/page_alloc: Work around a pahole limitation with zero-sized struct pagesets To: Christoph Hellwig Cc: Mel Gorman , 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 Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf29.hostedemail.com; dkim=pass header.d=gmail.com header.s=20161025 header.b=XNffNLoz; spf=pass (imf29.hostedemail.com: domain of andriinakryiko@gmail.com designates 209.85.219.175 as permitted sender) smtp.mailfrom=andriinakryiko@gmail.com; dmarc=pass (policy=none) header.from=gmail.com X-Rspamd-Server: rspam01 X-Rspamd-Queue-Id: BA5272D4 X-Stat-Signature: xefkfu1w1ymckznphbp4bug8dw6mcm76 X-HE-Tag: 1622126244-340854 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 2:19 AM Christoph Hellwig wrote: > > 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.