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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 5FD46C433ED for ; Sat, 17 Apr 2021 21:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 3A29161210 for ; Sat, 17 Apr 2021 21:29:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237137AbhDQV3a (ORCPT ); Sat, 17 Apr 2021 17:29:30 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:52768 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S237090AbhDQV32 (ORCPT ); Sat, 17 Apr 2021 17:29:28 -0400 Received: from casper.infradead.org (casper.infradead.org [IPv6:2001:8b0:10b:1236::1]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id B278FC061574; Sat, 17 Apr 2021 14:29:01 -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=tdMd9G9wD3dHdDB049z0mEp3bwlE87mJ0J7o89xl/iU=; b=kjCBnWRnNfJ4jh1gNX/lQqFZaV PIt6sDdbkDGzgmh71GE65C7gRjevycey4DoCtbejN9tL9oy21OFCEaAalEL1tJX2o90jMIunwvzlT aw6WnoUC4xKa/S6Fo+ZMatucihabyUEWmzgS2fQA3KuKU2AamMDSAvwzszyCc5I4TnWdPWLrwWCKi rVT5becyLy4eWu5C3CPFKJcjpScabeN83QGn+BwxjvQCu6su18nAbnPuTOLaKIYZFme9zSXfjcKXe HVFpVtf65QAh/PF06VB9QUA3eZMEV6/SGt6UIGiIg++xfTnOleyRsiTg4gP470cAho43TKpegokfh QjMDTCHQ==; Received: from willy by casper.infradead.org with local (Exim 4.94 #2 (Red Hat Linux)) id 1lXsUd-00BiOm-RD; Sat, 17 Apr 2021 21:28:45 +0000 Date: Sat, 17 Apr 2021 22:28:43 +0100 From: Matthew Wilcox To: David Laight Cc: "brouer@redhat.com" , "linux-kernel@vger.kernel.org" , "linux-mm@kvack.org" , "netdev@vger.kernel.org" , "linuxppc-dev@lists.ozlabs.org" , "linux-arm-kernel@lists.infradead.org" , "linux-mips@vger.kernel.org" , "ilias.apalodimas@linaro.org" , "mcroce@linux.microsoft.com" , "grygorii.strashko@ti.com" , "arnd@kernel.org" , "hch@lst.de" , "linux-snps-arc@lists.infradead.org" , "mhocko@kernel.org" , "mgorman@suse.de" Subject: Re: [PATCH 2/2] mm: Indicate pfmemalloc pages in compound_head Message-ID: <20210417212843.GT2531743@casper.infradead.org> References: <20210416230724.2519198-1-willy@infradead.org> <20210416230724.2519198-3-willy@infradead.org> <2a531a42f23e4046833e0feb8faef0b5@AcuMS.aculab.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <2a531a42f23e4046833e0feb8faef0b5@AcuMS.aculab.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Sat, Apr 17, 2021 at 09:13:45PM +0000, David Laight wrote: > > struct { /* page_pool used by netstack */ > > - /** > > - * @dma_addr: might require a 64-bit value on > > - * 32-bit architectures. > > - */ > > + unsigned long pp_magic; > > + unsigned long xmi; > > + unsigned long _pp_mapping_pad; > > unsigned long dma_addr[2]; > > }; > > You've deleted the comment. Yes. It no longer added any value. You can see dma_addr now occupies two words. > I also think there should be a comment that dma_addr[0] > must be aliased to ->index. That's not a requirement. Moving the pfmemalloc indicator is a requirement so that we _can_ use index, but there's no requirement about how index is used.