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=-4.0 required=3.0 tests=DKIMWL_WL_HIGH,DKIM_SIGNED, DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 5D8F9C4740C for ; Mon, 9 Sep 2019 18:15:01 +0000 (UTC) Received: from bombadil.infradead.org (bombadil.infradead.org [198.137.202.133]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 3519F218DE for ; Mon, 9 Sep 2019 18:15:01 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=lists.infradead.org header.i=@lists.infradead.org header.b="Aaoqniwc" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 3519F218DE Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed; d=lists.infradead.org; s=bombadil.20170209; h=Sender: Content-Transfer-Encoding:Content-Type:Cc:List-Subscribe:List-Help:List-Post: List-Archive:List-Unsubscribe:List-Id:MIME-Version:References:In-Reply-To: Date:To:From:Subject:Message-ID:Reply-To:Content-ID:Content-Description: Resent-Date:Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID: List-Owner; bh=6UO+umwIobRxkVAyS3o1jZsRj/uNa/O68TYGgMpZpBY=; b=AaoqniwcS9A9sn ym52jpmi0E0gvxPjBTmL8n4LnH6tGQiOmxaM1PiqyZC9tNlkTjKpEFt2fHgS8Ote9QZupCP+pLDKn V3c5WLzjav+S6NL6+INsATIJa5HrPHWca4K8i/hmxTu1qpYpWeWYMeNHMiUR3zB85luOkIx3XUGv+ BEWrVMRTHIRGfC0oNazfvkTLFPFlFvFZhrAE6dz2n7inufMz2AZ+V2M/nQYS7opObMLKPavOJWTgf YfKFk6oZ6QPbJQjJ8b4hqpfNv8/RdIwOinEVFd12NXRyi5NSZW+5xbx9nBwsBXTXKtg9K+2Dewr6s oFmxLD+Zmo7GGPFdCCWw==; Received: from localhost ([127.0.0.1] helo=bombadil.infradead.org) by bombadil.infradead.org with esmtp (Exim 4.92 #3 (Red Hat Linux)) id 1i7OBk-0002Vi-1V; Mon, 09 Sep 2019 18:14:56 +0000 Received: from mga02.intel.com ([134.134.136.20]) by bombadil.infradead.org with esmtps (Exim 4.92 #3 (Red Hat Linux)) id 1i7O9S-0008QG-VI for linux-arm-kernel@lists.infradead.org; Mon, 09 Sep 2019 18:12:36 +0000 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Sep 2019 11:12:34 -0700 X-IronPort-AV: E=Sophos;i="5.64,486,1559545200"; d="scan'208";a="178428271" Received: from ahduyck-desk1.jf.intel.com ([10.7.198.76]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 09 Sep 2019 11:12:33 -0700 Message-ID: <576de40e00083206bdb0c2e9f04fe34dd406e6b3.camel@linux.intel.com> Subject: Re: [PATCH v9 3/8] mm: Move set/get_pcppage_migratetype to mmzone.h From: Alexander Duyck To: "Kirill A. Shutemov" , Alexander Duyck Date: Mon, 09 Sep 2019 11:12:33 -0700 In-Reply-To: References: <20190907172225.10910.34302.stgit@localhost.localdomain> <20190907172528.10910.37051.stgit@localhost.localdomain> <20190909095608.jwachx3womhqmjbl@box> User-Agent: Evolution 3.30.5 (3.30.5-1.fc29) MIME-Version: 1.0 X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20190909_111235_070365_027FDEEC X-CRM114-Status: GOOD ( 22.19 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: yang.zhang.wz@gmail.com, pagupta@redhat.com, kvm@vger.kernel.org, david@redhat.com, catalin.marinas@arm.com, mhocko@kernel.org, linux-mm@kvack.org, will@kernel.org, aarcange@redhat.com, virtio-dev@lists.oasis-open.org, mst@redhat.com, willy@infradead.org, wei.w.wang@intel.com, ying.huang@intel.com, riel@surriel.com, dan.j.williams@intel.com, lcapitulino@redhat.com, linux-arm-kernel@lists.infradead.org, osalvador@suse.de, nitesh@redhat.com, konrad.wilk@oracle.com, dave.hansen@intel.com, linux-kernel@vger.kernel.org, pbonzini@redhat.com, akpm@linux-foundation.org, fengguang.wu@intel.com, kirill.shutemov@linux.intel.com Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+infradead-linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Mon, 2019-09-09 at 11:01 -0700, Alexander Duyck wrote: > On Mon, 2019-09-09 at 12:56 +0300, Kirill A. Shutemov wrote: > > On Sat, Sep 07, 2019 at 10:25:28AM -0700, Alexander Duyck wrote: > > > From: Alexander Duyck > > > > > > In order to support page reporting it will be necessary to store and > > > retrieve the migratetype of a page. To enable that I am moving the set and > > > get operations for pcppage_migratetype into the mm/internal.h header so > > > that they can be used outside of the page_alloc.c file. > > > > > > Reviewed-by: Dan Williams > > > Signed-off-by: Alexander Duyck > > > > I'm not sure that it's great idea to export this functionality beyond > > mm/page_alloc.c without any additional safeguards. How would we avoid to > > messing with ->index when the page is not in the right state of its > > life-cycle. Can we add some VM_BUG_ON()s here? > > I am not sure what we would need to check on though. There are essentially > 2 cases where we are using this. The first is the percpu page lists so the > value is set either as a result of __rmqueue_smallest or > free_unref_page_prepare. The second one which hasn't been added yet is for > the Reported pages case which I add with patch 6. > > When I use it for page reporting I am essentially using the Reported flag > to identify what pages in the buddy list will have this value set versus > those that may not. I didn't explicitly define it that way, but that is > how I am using it so that the value cannot be trusted unless the Reported > flag is set. I guess the alternative would be to just treat the ->index value as the index within the boundary array, and not use the per-cpu list functions. Doing that might make things a bit more clear since all we are really doing is storing the index into the boundary list the page is contained in. I could probably combine the value of order and migratetype and save myself a few cycles in the process by just saving the index into the array directly. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel