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 C4E35E732FD for ; Thu, 28 Sep 2023 17:38:02 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231945AbjI1RiC (ORCPT ); Thu, 28 Sep 2023 13:38:02 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:37608 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229478AbjI1RiB (ORCPT ); Thu, 28 Sep 2023 13:38:01 -0400 Received: from mgamail.intel.com (mgamail.intel.com [134.134.136.100]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0F16C1A2 for ; Thu, 28 Sep 2023 10:37:58 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1695922679; x=1727458679; h=message-id:date:mime-version:subject:to:cc:references: from:in-reply-to:content-transfer-encoding; bh=vUYvjPlgFPXD0fht4ZgNaZaIp5jz+/28FbQ6ukEjL3g=; b=gBtZaDc2sJaN0BETrgVLHQOX8l3Xr9GaoZkQHNhOBvNrNPZX1E2Q9b1z X/gE/ZTTLW1MLeZ+ipFOUadFDp8iYVaCM1f1MgIDJAUY3vxPOXjsKJgBf rHHHaCQdh+g+IZfEJJ8GLOWHXkl75ilV0EHlunYd88b0qpOC0TAVr6C8O dGz9aAObrxybCfo8zxMtch/GPGeCIoN9u09kasFedT2dQkoBSbIC6p9H1 ra3QaO0usqkLB6WeWMOtwsXhqd2hXsU58MO72V5C2x7XxZwagiTfSW1my MolbXl91p3WPzoJpXd3hr8fmvfjE0XmLXsHO50tm92RTQCnBhyRZzDWdM w==; X-IronPort-AV: E=McAfee;i="6600,9927,10847"; a="448618131" X-IronPort-AV: E=Sophos;i="6.03,184,1694761200"; d="scan'208";a="448618131" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by orsmga105.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Sep 2023 10:37:57 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=McAfee;i="6600,9927,10847"; a="699365408" X-IronPort-AV: E=Sophos;i="6.03,184,1694761200"; d="scan'208";a="699365408" Received: from jveerasa-mobl.amr.corp.intel.com (HELO [10.255.231.134]) ([10.255.231.134]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 28 Sep 2023 10:37:56 -0700 Message-ID: Date: Thu, 28 Sep 2023 10:37:56 -0700 MIME-Version: 1.0 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:102.0) Gecko/20100101 Thunderbird/102.15.1 Subject: Re: [RFC PATCH v2 0/7] Introduce persistent memory pool Content-Language: en-US To: David Hildenbrand , Stanislav Kinsburskii , Baoquan He Cc: tglx@linutronix.de, mingo@redhat.com, bp@alien8.de, dave.hansen@linux.intel.com, x86@kernel.org, hpa@zytor.com, ebiederm@xmission.com, akpm@linux-foundation.org, stanislav.kinsburskii@gmail.com, corbet@lwn.net, linux-kernel@vger.kernel.org, kexec@lists.infradead.org, linux-mm@kvack.org, kys@microsoft.com, jgowans@amazon.com, wei.liu@kernel.org, arnd@arndb.de, gregkh@linuxfoundation.org, graf@amazon.de, pbonzini@redhat.com References: <01828.123092517290700465@us-mta-156.us.mimecast.lan> <20230927161319.GA19976@skinsburskii.> From: Dave Hansen 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 9/28/23 10:35, David Hildenbrand wrote: > On 28.09.23 15:22, Dave Hansen wrote: >> On 9/27/23 09:13, Stanislav Kinsburskii wrote: >>> Once deposited, these pages can't be accessed by Linux anymore and thus >>> must be preserved in "used" state across kexec, as hypervisor state is >>> unware of kexec. >> >> If Linux can't access them, they're not RAM any more.  I'd much rather >> remove them from the memory map and move on with life rather than >> implement a bunch of new ABI that's got to be handed across kernels. > > The motivation of handling kexec (faster?) in a hyper-v domain doesn't > sound particularly compelling got me for such features. If you inflated > memory, just don't allow to kexec. It's been broken for years IIUC. That's a good point. What prevents deflating before kexec?