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From: Muchun Song In-Reply-To: Date: Tue, 24 Sep 2024 15:39:21 +0800 Cc: david@redhat.com, hughd@google.com, willy@infradead.org, vbabka@kernel.org, akpm@linux-foundation.org, rppt@kernel.org, vishal.moola@gmail.com, peterx@redhat.com, ryan.roberts@arm.com, christophe.leroy2@cs-soprasteria.com, linux-kernel@vger.kernel.org, linux-mm@kvack.org, linux-arm-kernel@lists.infradead.org, linuxppc-dev@lists.ozlabs.org Content-Transfer-Encoding: 7bit Message-Id: References: To: Qi Zheng X-Migadu-Flow: FLOW_OUT X-Stat-Signature: shrzhmn7xz74das3ijc7t5z3em1fz476 X-Rspamd-Queue-Id: E6A6040016 X-Rspam-User: X-Rspamd-Server: rspam10 X-HE-Tag: 1727163608-420897 X-HE-Meta: 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 0+PbDDLk ACw6uk6U3ZQylf82SSab2LcHmOmPhPdU6jievHwvnY43ShpKJeG0tYzS7fM7rKFi6HYBNlmDc173IdtDN7+qG9KEpQWeBDI+ns7G7kbKwcTUC2qn2ncc8GQ2js1JUMshzsL5gYacDmAQ8yCx2EwM0xeq7wqVFSGZFqXnvS8SQHNaFo6HcxGsgnMNTS81dbL2rMKZRTEg9k38mzOH23jv6aWXrVOFoxRN+/O0k9ZXGj5PXZXeGM4e8NshIKjuR2QvZ+ECRZ15DZcgc0HcZVSKC7kQQkuRpKYDcKBDCCeEEW8+ATysRvhDHhFHCDK45P30S3jjxvrXV4lWTyeI2/MlD0vXaLg== 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 Sep 24, 2024, at 14:10, Qi Zheng wrote: > > In move_ptes(), we may modify the new_pte after acquiring the new_ptl, so > convert it to using pte_offset_map_rw_nolock(). Now new_pte is none, so > hpage_collapse_scan_file() path can not find this by traversing > file->f_mapping, so there is no concurrency with retract_page_tables(). In > addition, we already hold the exclusive mmap_lock, so this new_pte page is > stable, so there is no need to get pmdval and do pmd_same() check. > > Signed-off-by: Qi Zheng Reviewed-by: Muchun Song