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[2003:cb:c718:f00:b37d:4253:cd0d:d213]) by smtp.gmail.com with ESMTPSA id x5-20020a05600c21c500b0040644e699a0sm4315192wmj.45.2023.09.28.10.35.32 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Thu, 28 Sep 2023 10:35:33 -0700 (PDT) Message-ID: Date: Thu, 28 Sep 2023 19:35:32 +0200 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 To: Dave Hansen , 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: David Hildenbrand Organization: Red Hat In-Reply-To: X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Language: en-US Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Queue-Id: 1CE564001A X-Rspam-User: X-Stat-Signature: k9n55j54azkkfwdtwh8fbwwimybsqa71 X-Rspamd-Server: rspam01 X-HE-Tag: 1695922537-293932 X-HE-Meta: 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 F19K3MuC BEvEgE11gQuAcuB2FJzBP+IjlCg1aywzytfW/FmJaBz1mnECtVFrHvu6N7w8na6i3tHPYbAfJ1Yh75MqDkMGZ/DfrchoDGpWgbBimHUnkrPLUP4w8onuAiIKxQlqsBlrnH3UCI9l6+VQSsCUTxIR5qguTGDbguYDZVOib3WVZ/qrPgZfnVBXcF51V5YFW5tdw0uwwINRu0JjYNF70wcL0lEYNcLrTT9eukHmZUPYez5N9mx65LTgpYNtgcFxRtAs59vMBdb9jnQVYG7NJ9W1FRUSFCP4kFkHpYWc0kYLEquVZWq1OiACYISjqAPlPStVIyTC8FlZXof61qErkIUga6ENxBHL0kHGI89AJWHJhiiZx271VGYoATZ7tlIhCVGQ6L/D51lRzt1TC08Qet0pKkHB32dKM+ZBg1LH1SVuIsXNiEdBHdssxRA9IIdsrB0+7Ebvoiy7gJXCDqec= 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 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. Maybe the other use cases are more "relevant". -- Cheers, David / dhildenb