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=-10.8 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 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 3C211C4743E for ; Fri, 4 Jun 2021 19:08:31 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 256F6601FA for ; Fri, 4 Jun 2021 19:08:31 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S230284AbhFDTKQ (ORCPT ); Fri, 4 Jun 2021 15:10:16 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:53020 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229823AbhFDTKL (ORCPT ); Fri, 4 Jun 2021 15:10:11 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 618FEC061766; Fri, 4 Jun 2021 12:08:16 -0700 (PDT) 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=qQJztOodfoxDWJWTnTGER2fqF43sT9h5HGGsfs/kKc0=; b=RUDpKiS57Vx8hvZdyqvbgHmfb7 36Dn56mc7iMBpkAmAAlZRvrv1Zz+hlG8nKJFbgKZVi40T+Ti5TMzurbwhI6sHrcoqECTEJp9CF6Q8 AtJgqlJT577/KqB9ihV8a4o4ez+QVZZ7CgM9WhGQMK+jym2tUweH+SywM7HeXQ1ma75t5yjUx3UPL bkCjtspA1tAAICy9NhLYGco8xJJE66llfOZGS7i+lRYc8pxz/AjiwkSAwxq8m3ofSmomd1MfZHgkA nArM1fkk0p03my+iWdXcy2/iT0Ng3PkPEmQeBr+GCcqf160zngXHXCXy/Ezn/iRKE/sWM8vpFp9z4 jlATDaNQ==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lpFAl-00DVBg-Kk; Fri, 04 Jun 2021 19:08:03 +0000 Date: Fri, 4 Jun 2021 20:07:59 +0100 From: Matthew Wilcox To: Matteo Croce 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 Subject: Re: [PATCH net-next v7 1/5] mm: add a signature in struct page Message-ID: References: <20210604183349.30040-1-mcroce@linux.microsoft.com> <20210604183349.30040-2-mcroce@linux.microsoft.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20210604183349.30040-2-mcroce@linux.microsoft.com> Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On Fri, Jun 04, 2021 at 08:33:45PM +0200, Matteo Croce wrote: > @@ -130,7 +137,10 @@ struct page { > }; > }; > struct { /* Tail pages of compound page */ > - unsigned long compound_head; /* Bit zero is set */ > + /* Bit zero is set > + * Bit one if pfmemalloc page > + */ > + unsigned long compound_head; I would drop this hunk. Bit 1 is not used for this purpose in tail pages; it's used for that purpose in head and base pages. I suppose we could do something like ... static inline void set_page_pfmemalloc(struct page *page) { - page->index = -1UL; + page->lru.next = (void *)2; } if it's causing confusion.