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 Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 3AD5EC433F5 for ; Fri, 3 Dec 2021 18:20:57 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1382558AbhLCSYR (ORCPT ); Fri, 3 Dec 2021 13:24:17 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]:50888 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1382554AbhLCSYN (ORCPT ); Fri, 3 Dec 2021 13:24:13 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1638555649; 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=qgsO3oHAmFJzKq+dVmJv06T3M/ORmohx5le6ux9ty9c=; b=bhHBJvxiCWUR7VbhYghOxUAsBMzqMUHmBzvarYUAVK4RFNESORb5UiThllxjfUWSJFOYsP xrfHMd963etXqtitrFa+4VSDhMgOUh8rDxwzcoC/HRM4lLzhWjAs3QXenA3Z1vKTIbPKM7 yM0qYmKX0uscRwoQMCbW4ecRNNleJYQ= Received: from mail-wm1-f70.google.com (mail-wm1-f70.google.com [209.85.128.70]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-429-gdKGskOcMl65EJmEf3iUFA-1; Fri, 03 Dec 2021 13:20:48 -0500 X-MC-Unique: gdKGskOcMl65EJmEf3iUFA-1 Received: by mail-wm1-f70.google.com with SMTP id g80-20020a1c2053000000b003331a764709so3818722wmg.2 for ; Fri, 03 Dec 2021 10:20:47 -0800 (PST) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=x-gm-message-state:message-id:date:mime-version:user-agent:subject :content-language:to:cc:references:from:organization:in-reply-to :content-transfer-encoding; bh=qgsO3oHAmFJzKq+dVmJv06T3M/ORmohx5le6ux9ty9c=; b=ItdfjF9zDesYrsnDxceXUkatfr4wG5M/dflJHQjlP26ZzwloS6vrs8c6MhAo28Ufjs NmN+NMa20PXyTKPNMw2R50otEjwmeo0hWzRn+0ttithcu2LLc6OEILQVj64fR6XWMzyd KhLrh40nDhlSe//dFd+s6Y+hYbHr5t7cFgR74RcRDFnoJFC6n9WaRVr59WLjH056RO+V 4Bcu+9MqG/bi3zQckGyyDoqfx0n6YuX0jPhnFoTIy21nNC0bLhiyDxBxfTMmu+c+RepT rSKfk5mMTgdWDmX1GGH2rC94ObcsDgFDGlp4PB+bs5jSsJURmbjpGt2xZ5m3UyfhHSGy RHzg== X-Gm-Message-State: AOAM530AeaWDISxvVRTAoAK8S1Q48wT+nk0a1pc5/pxZd5JyvEGQIdE9 us0Q9Q2bbzwjQpmcb+W+D/O/tpCLf/QSthku0RZY5m3k9q1IbygoYl4J4LK0kamr4SmA1nPI+km vWKdBZ/Ua3yv8SjJllT9srvkH X-Received: by 2002:a05:6000:2c7:: with SMTP id o7mr24017457wry.62.1638555647057; Fri, 03 Dec 2021 10:20:47 -0800 (PST) X-Google-Smtp-Source: ABdhPJy8CavJ4evptW+LbrLlZf/myYwiY1F8lIjOYR0WgVLxsVzfjSUUsdpB9qGAHvDNHYUc5Gd9IQ== X-Received: by 2002:a05:6000:2c7:: with SMTP id o7mr24017435wry.62.1638555646881; Fri, 03 Dec 2021 10:20:46 -0800 (PST) Received: from ?IPV6:2003:d8:2f44:9200:3344:447e:353c:bf0b? (p200300d82f4492003344447e353cbf0b.dip0.t-ipconnect.de. [2003:d8:2f44:9200:3344:447e:353c:bf0b]) by smtp.gmail.com with ESMTPSA id l22sm3203749wmp.34.2021.12.03.10.20.46 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 03 Dec 2021 10:20:46 -0800 (PST) Message-ID: <1e0ce8f6-332b-399f-5ac7-5a56639172b3@redhat.com> Date: Fri, 3 Dec 2021 19:20:45 +0100 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:91.0) Gecko/20100101 Thunderbird/91.2.0 Subject: Re: [RFD] clear virtual machine memory when virtual machine is turned off Content-Language: en-US To: Mike Kravetz , fei luo , akpm@linux-foundation.org, arnd@arndb.de, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arch@vger.kernel.org Cc: Joao Martins References: <673c5628-da97-83d3-028f-46219f203caf@redhat.com> From: David Hildenbrand Organization: Red Hat In-Reply-To: Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 02.12.21 18:27, Mike Kravetz wrote: > On 12/2/21 04:47, David Hildenbrand wrote: >> On 02.12.21 11:19, fei luo wrote: >>> >>> When reusing the page that has been cleared, there is no need to clear it >>> >>> again, which also speeds up the memory allocation of user-mode programs. >>> >>> >>> Is this feature feasible? >> >> "init_on_free=1" for the system as a whole, which might sounds like what >> might tackle part of your use case. >> > > Certainly init_on_free will not make much difference if VMs are backed by > hugetlb pages. We (Joao and myself) have thought about clearing hugetlb > pages from user space in an attempt speed up launching of VMs backed by > hugetlb pages. > I remember that discussion. And I also recall a discussion regarding extending init_on_free semantics to hugetlbfs. -- Thanks, David / dhildenb