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=-18.3 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_IN_DEF_DKIM_WL autolearn=unavailable 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 57D3DC4743F for ; Mon, 7 Jun 2021 13:59:03 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id BD5BD61185 for ; Mon, 7 Jun 2021 13:59:02 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org BD5BD61185 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.microsoft.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 4B2A56B006C; Mon, 7 Jun 2021 09:59:02 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id 462C46B006E; Mon, 7 Jun 2021 09:59:02 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 2B61F6B0070; Mon, 7 Jun 2021 09:59:02 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0173.hostedemail.com [216.40.44.173]) by kanga.kvack.org (Postfix) with ESMTP id EDC7B6B006C for ; Mon, 7 Jun 2021 09:59:01 -0400 (EDT) Received: from smtpin31.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 8AD2EBF03 for ; Mon, 7 Jun 2021 13:59:01 +0000 (UTC) X-FDA: 78227084082.31.62AD3EB Received: from linux.microsoft.com (linux.microsoft.com [13.77.154.182]) by imf06.hostedemail.com (Postfix) with ESMTP id CE914C00CBE4 for ; Mon, 7 Jun 2021 13:58:58 +0000 (UTC) Received: from mail-pg1-f173.google.com (mail-pg1-f173.google.com [209.85.215.173]) by linux.microsoft.com (Postfix) with ESMTPSA id 1AC0020B8768 for ; Mon, 7 Jun 2021 06:59:00 -0700 (PDT) DKIM-Filter: OpenDKIM Filter v2.11.0 linux.microsoft.com 1AC0020B8768 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.microsoft.com; s=default; t=1623074340; bh=RJbR6n7tHj/RCUL2D5DbLcr8QLAchc6CH5JQTYC4VdU=; h=References:In-Reply-To:From:Date:Subject:To:Cc:From; b=oQU/hnEuNYU38+smF6MWg1KNkHCYkUHjtBkKSJD5GNOnbxCRhgBqAPRIVlSqjH3oR 0uBJdxzGbU5YfXyOK2NWS2yVSVG4XQt/uZNy8E5W7mvZJQI0DS8YGu1Ls/+xETunZv i4IzU+ETAnolFaL7WEIfXbDma9VbRfj4wcXsF2QE= Received: by mail-pg1-f173.google.com with SMTP id r1so13858484pgk.8 for ; Mon, 07 Jun 2021 06:59:00 -0700 (PDT) X-Gm-Message-State: AOAM5309OBnx5WrBUNx6mmPH5lfL38ma3gMQyKpdB3YhCYCBugQkGkgY pFxUYha+Z+mcfAPva6jUs75M1JCnz6XU//iN90s= X-Google-Smtp-Source: ABdhPJzrHLqPChd08nP1N0FnCsUSWppo+7N/IfO51VOEQxz8ChUp/9waJhKWDPkGBpNi/mUbAds+1gb+BPlL1TqNxko= X-Received: by 2002:aa7:900f:0:b029:2ec:82d2:d23 with SMTP id m15-20020aa7900f0000b02902ec82d20d23mr15780817pfo.16.1623074339484; Mon, 07 Jun 2021 06:58:59 -0700 (PDT) MIME-Version: 1.0 References: <20210604183349.30040-1-mcroce@linux.microsoft.com> <20210604183349.30040-2-mcroce@linux.microsoft.com> In-Reply-To: From: Matteo Croce Date: Mon, 7 Jun 2021 15:58:23 +0200 X-Gmail-Original-Message-ID: Message-ID: Subject: Re: [PATCH net-next v7 1/5] mm: add a signature in struct page To: Matthew Wilcox Cc: netdev@vger.kernel.org, linux-mm@kvack.org, Ayush Sawal , Vinay Kumar Yadav , Rohit Maheshwari , "David S. Miller" , Jakub Kicinski , Thomas Petazzoni , Marcin Wojtas , Russell King , Mirko Lindner , Stephen Hemminger , Tariq Toukan , Jesper Dangaard Brouer , Ilias Apalodimas , Alexei Starovoitov , Daniel Borkmann , John Fastabend , Boris Pismenny , Arnd Bergmann , Andrew Morton , "Peter Zijlstra (Intel)" , Vlastimil Babka , Yu Zhao , Will Deacon , Fenghua Yu , Roman Gushchin , Hugh Dickins , Peter Xu , Jason Gunthorpe , Jonathan Lemon , Alexander Lobakin , Cong Wang , wenxu , Kevin Hao , Jakub Sitnicki , Marco Elver , Willem de Bruijn , Miaohe Lin , Yunsheng Lin , Guillaume Nault , linux-kernel@vger.kernel.org, linux-rdma@vger.kernel.org, bpf@vger.kernel.org, Eric Dumazet , David Ahern , Lorenzo Bianconi , Saeed Mahameed , Andrew Lunn , Paolo Abeni , Sven Auhagen Content-Type: text/plain; charset="UTF-8" Authentication-Results: imf06.hostedemail.com; dkim=pass header.d=linux.microsoft.com header.s=default header.b="oQU/hnEu"; spf=pass (imf06.hostedemail.com: domain of mcroce@linux.microsoft.com designates 13.77.154.182 as permitted sender) smtp.mailfrom=mcroce@linux.microsoft.com; dmarc=pass (policy=none) header.from=linux.microsoft.com X-Stat-Signature: cphd9b4t1w3ds79kcnsu9gn9pqqyyeoz X-Rspamd-Queue-Id: CE914C00CBE4 X-Rspamd-Server: rspam06 X-HE-Tag: 1623074338-975428 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 Mon, Jun 7, 2021 at 3:53 PM Matthew Wilcox wrote: > > On Sun, Jun 06, 2021 at 03:50:54AM +0200, Matteo Croce wrote: > > And change all the *_pfmemalloc functions to use page->lru.next like this? > > > > @@ -1668,10 +1668,12 @@ struct address_space *page_mapping(struct page *page); > > static inline bool page_is_pfmemalloc(const struct page *page) > > { > > /* > > - * Page index cannot be this large so this must be > > - * a pfmemalloc page. > > + * This is not a tail page; compound_head of a head page is unused > > + * at return from the page allocator, and will be overwritten > > + * by callers who do not care whether the page came from the > > + * reserves. > > */ > > The comment doesn't make a lot of sense if we're switching to use > lru.next. How about: > > /* > * lru.next has bit 1 set if the page is allocated from the > * pfmemalloc reserves. Callers may simply overwrite it if > * they do not need to preserve that information. > */ Sounds good! -- per aspera ad upstream