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X-IronPort-AV: E=McAfee;i="6600,9927,10847"; a="448618128" X-IronPort-AV: E=Sophos;i="6.03,184,1694761200"; d="scan'208";a="448618128" 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 X-Rspamd-Queue-Id: 816A74001B X-Rspam-User: X-Rspamd-Server: rspam05 X-Stat-Signature: oj4j45nrym6kr8j4u1punkt7n1c7dei8 X-HE-Tag: 1695922680-951554 X-HE-Meta: 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 fzY+pTwp zwq53GMmpZZnY2atnfiH80Feg61lN7l2XL44M1KLZ2xZCgzJCOYFYN6mbo11CaUADHq2M2nm4Y0EzxPgeywvNcZdDiFkIA26bPKL8FcO91h6cvYsggJTU+31IFxuCwy8fgw2ejigpjilanHR4hAL2ULvM92GcNvUlWPSSMkBjR+J/1kl7goF0XCIQGB67n788SnqohdsrcUyDxed4Qz2u599srS2sj/z6tdv4grGh85K5HDJ37OTXb8YedQ== 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 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?