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b=LpWR43F9hquCPkE/fuRAr/7u3FSeCqf2wjV+XkSXXm6oeymE5Fj9Wup2x1RkIlqdd EiVRIyKO/uSb5Nj3jcZr0X/wLJsC88vY5zBKaXIn7dD8YA2PDRqXrOMl/VH4OigS4h 5S0o03LKKfqJUHW8yMmG8lIppu4thk95FB5aLTYW7JKJmCkNE/tn+OCmy2dvEEV3MV WY2SYXcG7D1CWXVh81g2uicXW/8DYS2b/Odd7UtpKegga+28jO+BQCd74+Zn3QpghJ rCVtXMm/MLDK6bKRVhU4WpzmDi3rfVwgbK6wkO1FZp2sCLsXtmREfdxkaDgLbpf7ka BEH81+FmWjrlA== Message-ID: Date: Thu, 12 Feb 2026 21:13:28 +0100 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH mm-unstable v1 1/5] mm: consolidate anonymous folio PTE mapping into helpers To: Zi Yan , Nico Pache Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org, aarcange@redhat.com, akpm@linux-foundation.org, anshuman.khandual@arm.com, apopple@nvidia.com, baohua@kernel.org, baolin.wang@linux.alibaba.com, byungchul@sk.com, catalin.marinas@arm.com, cl@gentwo.org, corbet@lwn.net, dave.hansen@linux.intel.com, dev.jain@arm.com, gourry@gourry.net, hannes@cmpxchg.org, hughd@google.com, jackmanb@google.com, jack@suse.cz, jannh@google.com, jglisse@google.com, joshua.hahnjy@gmail.com, kas@kernel.org, lance.yang@linux.dev, Liam.Howlett@oracle.com, lorenzo.stoakes@oracle.com, mathieu.desnoyers@efficios.com, matthew.brost@intel.com, mhiramat@kernel.org, mhocko@suse.com, peterx@redhat.com, pfalcato@suse.de, rakie.kim@sk.com, raquini@redhat.com, rdunlap@infradead.org, richard.weiyang@gmail.com, rientjes@google.com, rostedt@goodmis.org, rppt@kernel.org, ryan.roberts@arm.com, shivankg@amd.com, sunnanyong@huawei.com, surenb@google.com, thomas.hellstrom@linux.intel.com, tiwai@suse.de, usamaarif642@gmail.com, vbabka@suse.cz, vishal.moola@gmail.com, wangkefeng.wang@huawei.com, will@kernel.org, willy@infradead.org, yang@os.amperecomputing.com, ying.huang@linux.alibaba.com, zokeefe@google.com References: <20260212021835.17755-1-npache@redhat.com> <20260212021835.17755-2-npache@redhat.com> <048C7077-3E54-4DFE-A25D-05D3CCB132D6@nvidia.com> <079A6B19-00E6-4895-AFF7-3F7CEED4170B@nvidia.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; 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charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspamd-Server: rspam09 X-Rspamd-Queue-Id: AF2B6140007 X-Stat-Signature: pgnem93jsa8hhcqjy41t1sytucejs1nb X-Rspam-User: X-HE-Tag: 1770927224-53498 X-HE-Meta: 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 S8d4GSRN RX8mcRkw/7X6+uICWb09ND46ETAgRFz8eW3bSX7DU0tn9HwHQgpZXv8W60U5B5u7cALjIb7Gwe9NWE8/kBu/KooHU7d4p0KdWQw55DniAHMbAiuJK9YeZJJITvYER103JiDByph4c5YYb/A/dA1i3dfBmqI88Y4czsElAuRewkoYOLW3DaWzNLbVL44tY6g7tqf1hQ6gxVZlXks3HNjkUYhe66NkbFoxRFj9Hif7gqqI67OcOAETLBnJnZSejAcc/7C3b31pMJeN8JQrrHJ+vSHFvrDPKO3MmKnraCTK2MDEeAxzkqYvZoXkoq3VkuOav58a42AAMlwmQkQs= 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: On 2/12/26 21:06, Zi Yan wrote: > > >>> >>> >>> OK, this becomes maybe_mkwrite(pte_mkdirty(entry), vma). >> >> Yes, upon further investigation this does seem to slightly change the behavior. > > I did not notice it when I was reviewing it. ;) > >> >> pte_mkdirty() is now being called unconditionally from the VM_WRITE >> flag. I noticed other callers in the kernel doing this too. >> >> Is it ok to leave the pte_mkdirty() or should I go back to using >> pte_mkwrite with the conditional guarding both mkwrite and mkdirty? > > > IMHO, it is better to use the conditional guarding way. > We reach here when userspace reads an address (VM_WRITE is not set) > and no zero page is used. Using maybe_mkwrite(pte_mkdirty(entry), vma) > means we will get a dirty PTE pointing to the allocated page but user > only reads from it. In general, it's best to not perform any such changes as part of a bigger patch. :) -- Cheers, David