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[2003:cb:c721:a000:7426:f6b4:82a3:c6ab]) by smtp.gmail.com with ESMTPSA id k24-20020a5d5258000000b00332c0aace23sm3722896wrc.105.2023.11.24.00.53.02 (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128); Fri, 24 Nov 2023 00:53:02 -0800 (PST) Message-ID: <1fb403e1-58f0-414c-be36-4872bc0ac0ae@redhat.com> Date: Fri, 24 Nov 2023 09:53:01 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v2 01/14] mm: Batch-copy PTE ranges during fork() To: Ryan Roberts , Catalin Marinas , Will Deacon , Ard Biesheuvel , Marc Zyngier , Oliver Upton , James Morse , Suzuki K Poulose , Zenghui Yu , Andrey Ryabinin , Alexander Potapenko , Andrey Konovalov , Dmitry Vyukov , Vincenzo Frascino , Andrew Morton , Anshuman Khandual , Matthew Wilcox , Yu Zhao , Mark Rutland , Kefeng Wang , John Hubbard , Zi Yan Cc: linux-arm-kernel@lists.infradead.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org References: <20231115163018.1303287-1-ryan.roberts@arm.com> <20231115163018.1303287-2-ryan.roberts@arm.com> <89a9fe07-a5c5-4a99-b588-e6145053c58f@redhat.com> <1459f78b-e80c-4f21-bc65-f0ab259d348a@arm.com> <08ef2c36-2b9c-4b96-9d1d-68cca0f68ba5@redhat.com> <2d027a8d-adfb-481d-89ea-c99139e669aa@arm.com> <2618b024-6a95-4bfc-a08d-59d86e9931e5@redhat.com> <118eb2d3-d504-49f0-b7f2-f29b64a8f404@arm.com> <15e2c6cb-e86d-417b-b83d-7c7459d5be8f@redhat.com> <42f9e03f-86ad-418e-a337-7aef202e6a5b@arm.com> From: David Hildenbrand Autocrypt: addr=david@redhat.com; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Stat-Signature: frt5gpid97hqyzn55e1qw4w1mgng36bj X-Rspamd-Server: rspam07 X-Rspamd-Queue-Id: 755462001E X-HE-Tag: 1700815987-411660 X-HE-Meta: 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 K9yyui9+ 0wOfrzIr7OAIOW5x9tft8FeOAazb5f3RYxeWWC8kAwOQUTs6gcaKT2/uBhVDP1ve8sJrkQYbelBGNuTmK3jXBiAOaCV61o6pQCv4vc3PvDqAXW7OnIhkDDgJ8UjxKz2cRWLnp7dVgn55TkEG9SwMXnd+CRkJMVnXzR51goavR2c3WHDcCgPmxqELFJA7/Z9lFTL07oFrb1gpsKZsmGHXJe8B/ntXeVFphePZSvKubmS4VfWRc6vi8xfYrdoplfpCcnZhezeCAWOQQNXwfQ2MZaZm0x0hmND4QPWcrroF4P1WBDcU2RDTpvJz57DyMoCK0uz3eGc6yXc30R6qEaqcGJ0/JsWT6gmkMsmz5g3b1qvABaDoQxKjnLzvLMa1AkkcZD/vio3rlvz0kmWbp2dk7pK6TW7DVHm12KelvYE/erqxiG7ev5xBw9Aq0QDEafC4bo4kxxedYkvPpAE7YRJFrHgbUagPjOMFairp+l1UgdzeiyNE= 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: List-Subscribe: List-Unsubscribe: >> One could simply skip batching for now on pte_protnone() and focus on the >> "writable" vs. "not-writable". > > I'm not sure we can simply "skip" batching on pte_protnone() since we will need > to terminate the batch if we spot it. But if we have to look for it anyway, we > might as well just terminate the batch when the value of pte_protnone() > *changes*. I'm also proposing to take this approach for pte_uffd_wp() which also > needs to be carefully preserved per-pte. Yes, that's what I meant. -- Cheers, David / dhildenb