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=-7.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 0C30FC433DB for ; Mon, 22 Feb 2021 13:22:58 +0000 (UTC) Received: from kanga.kvack.org (kanga.kvack.org [205.233.56.17]) by mail.kernel.org (Postfix) with ESMTP id 8545664E40 for ; Mon, 22 Feb 2021 13:22:57 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 8545664E40 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=owner-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix) id B5DD96B0087; Mon, 22 Feb 2021 08:22:56 -0500 (EST) Received: by kanga.kvack.org (Postfix, from userid 40) id AE7E36B0088; Mon, 22 Feb 2021 08:22:56 -0500 (EST) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id 9ADCD8D0005; Mon, 22 Feb 2021 08:22:56 -0500 (EST) X-Delivered-To: linux-mm@kvack.org Received: from forelay.hostedemail.com (smtprelay0084.hostedemail.com [216.40.44.84]) by kanga.kvack.org (Postfix) with ESMTP id 830FB6B0087 for ; Mon, 22 Feb 2021 08:22:56 -0500 (EST) Received: from smtpin22.hostedemail.com (10.5.19.251.rfc1918.com [10.5.19.251]) by forelay02.hostedemail.com (Postfix) with ESMTP id 40AF96D92 for ; Mon, 22 Feb 2021 13:22:56 +0000 (UTC) X-FDA: 77845969152.22.5555159 Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [63.128.21.124]) by imf27.hostedemail.com (Postfix) with ESMTP id 8CB8E80192C7 for ; Mon, 22 Feb 2021 13:22:50 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1614000175; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=QRsNQR46kCoWJ5LwqQ/hYDavqNf0sAJPGKLdOJIj1SE=; b=YRecH139FVKHx7OdRTTI0skxMykbm3d2J1eEZHqI9h+OVtJGg667r1EtyHyVkDcMrMaf2Q iPJf1N1Ep03UhqEkpDTk5gvjZvpTxZkeVbZ9kC7E4b0elyhbDJO4AXm/pQn1TVCAKjwGkh ww7KEE39DhGj3KdjBJHWgXvC71FwJ1Q= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-408-3PSoCvXGM7mZVcLSo73BrA-1; Mon, 22 Feb 2021 08:22:51 -0500 X-MC-Unique: 3PSoCvXGM7mZVcLSo73BrA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 00B44835E23; Mon, 22 Feb 2021 13:22:48 +0000 (UTC) Received: from [10.36.115.16] (ovpn-115-16.ams2.redhat.com [10.36.115.16]) by smtp.corp.redhat.com (Postfix) with ESMTP id E80F760C17; Mon, 22 Feb 2021 13:22:38 +0000 (UTC) Subject: Re: [PATCH RFC] mm/madvise: introduce MADV_POPULATE to prefault/prealloc memory To: Michal Hocko Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, Andrew Morton , Arnd Bergmann , Oscar Salvador , Matthew Wilcox , Andrea Arcangeli , Minchan Kim , Jann Horn , Jason Gunthorpe , Dave Hansen , Hugh Dickins , Rik van Riel , "Michael S . Tsirkin" , "Kirill A . Shutemov" , Vlastimil Babka , Richard Henderson , Ivan Kokshaysky , Matt Turner , Thomas Bogendoerfer , "James E.J. Bottomley" , Helge Deller , Chris Zankel , Max Filippov , linux-alpha@vger.kernel.org, linux-mips@vger.kernel.org, linux-parisc@vger.kernel.org, linux-xtensa@linux-xtensa.org, linux-arch@vger.kernel.org References: <20210217154844.12392-1-david@redhat.com> <640738b5-a47e-448b-586d-a1fb80131891@redhat.com> <73f73cf2-1b4e-bfa9-9a4c-3192d7b7a5ec@redhat.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <3b5cd68d-c4ac-c6be-8824-34c541d5377b@redhat.com> Date: Mon, 22 Feb 2021 14:22:37 +0100 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101 Thunderbird/78.7.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 X-Rspamd-Server: rspam04 X-Rspamd-Queue-Id: 8CB8E80192C7 X-Stat-Signature: oizhsfzur4a5in5qhn3csjhs1rn8as5r Received-SPF: none (redhat.com>: No applicable sender policy available) receiver=imf27; identity=mailfrom; envelope-from=""; helo=us-smtp-delivery-124.mimecast.com; client-ip=63.128.21.124 X-HE-DKIM-Result: pass/pass X-HE-Tag: 1614000170-835777 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: >> Exactly. But for hugetlbfs/shmem ("!RAM-backed files") this is not what we >> want. > > OK, then I must have misread your requirements. Maybe I just got lost in > all the combinations you have listed. Another special case could be dax/pmem I think. You might want to fault it in readable/writable but not perform an actual read/write unless really required. QEMU phrases this as "don't cause wear on the storage backing". -- Thanks, David / dhildenb