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 B8978C433E0 for ; Tue, 5 Jan 2021 07:50:33 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 360AC21973 for ; Tue, 5 Jan 2021 07:50:33 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 360AC21973 Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id 77BBC8D0063; Tue, 5 Jan 2021 02:50:32 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id 72B9E8D0036; Tue, 5 Jan 2021 02:50:32 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 6414B8D0063; Tue, 5 Jan 2021 02:50:32 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0101.hostedemail.com [216.40.44.101]) by kanga.kvack.org (Postfix) with ESMTP id 73DCA8D0036 for ; Tue, 5 Jan 2021 02:50:31 -0500 (EST) Received: from smtpin28.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay04.hostedemail.com (Postfix) with ESMTP id 3E79D1EE6 for ; Tue, 5 Jan 2021 07:50:31 +0000 (UTC) X-FDA: 77670949062.28.map56_590966e274d7 Received: from filter.hostedemail.com (10.5.16.251.rfc1918.com [10.5.16.251]) by smtpin28.hostedemail.com (Postfix) with ESMTP id 235ED6C11 for ; Tue, 5 Jan 2021 07:50:31 +0000 (UTC) X-HE-Tag: map56_590966e274d7 X-Filterd-Recvd-Size: 2582 Received: from mx2.suse.de (mx2.suse.de [195.135.220.15]) by imf33.hostedemail.com (Postfix) with ESMTP for ; Tue, 5 Jan 2021 07:50:30 +0000 (UTC) X-Virus-Scanned: by amavisd-new at test-mx.suse.de DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1; t=1609833029; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc: mime-version:mime-version:content-type:content-type: in-reply-to:in-reply-to:references:references; bh=zN1ZQptkDr2Sx20lZHpIUYbZZweZ0jHrozA2d7eEC+c=; b=EPW3hX0CHvyETxVQ+oZKb2FjUUWU1c6cS30QrikW+VmFz1wBFlbSlKVUeXjGw2U+864x01 jpK6IoTPuN1gR5ftY4QdElRbV2wI/xy4Lxupa69QEUDRWtVTmxGEsJzk3tn3A+/Ibyeagu Sioj6pFN6/sJP4frdYjP14ZOKNjwChk= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id 72744ACAF; Tue, 5 Jan 2021 07:50:29 +0000 (UTC) Date: Tue, 5 Jan 2021 08:50:28 +0100 From: Michal Hocko To: Dan Williams Cc: David Hildenbrand , Linux MM , LKML Subject: Re: uninitialized pmem struct pages Message-ID: <20210105075028.GS13207@dhcp22.suse.cz> References: <20210104100323.GC13207@dhcp22.suse.cz> <033e1cd6-9762-5de6-3e88-47d3038fda7f@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: 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 04-01-21 21:17:43, Dan Williams wrote: > On Mon, Jan 4, 2021 at 2:45 AM David Hildenbrand wrote: [...] > > I believe Dan mentioned somewhere that he wants to see a real instance > > of this producing a BUG before actually moving forward with a fix. I > > might be wrong. > > I think I'm missing an argument for the user-visible effects of the > "Bad." statements above. I think soft_offline_page() is a candidate > for a local fix because mm/memory-failure.c already has a significant > amount of page-type specific knowledge. So teaching it "yes" for > MEMORY_DEVICE_PRIVATE-ZONE_DEVICE and "no" for other ZONE_DEVICE seems > ok to me. I believe we do not want to teach _every_ pfn walker about zone device pages. This would be quite error prone. Especially when a missig check could lead to a silently broken data or BUG_ON with debugging enabled (which is not the case for many production users). Or are we talking about different bugs here? -- Michal Hocko SUSE Labs