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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Shuah Khan , linux-btrfs@vger.kernel.org, linux-kernel@vger.kernel.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kselftest@vger.kernel.org References: <20260424024915.28758-1-ziy@nvidia.com> <20260424024915.28758-3-ziy@nvidia.com> From: Baolin Wang In-Reply-To: <20260424024915.28758-3-ziy@nvidia.com> Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Queue-Id: 4ACAF80003 X-Rspamd-Server: rspam04 X-Stat-Signature: r5ftoqu9bnz4e1p8k8kq9g5entrzyseq X-HE-Tag: 1777183297-473315 X-HE-Meta: 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 yAG31o45 fFrW4FoWkE77cOWrFILUbgQvRar3Lt/TBxIMyNBL3bKDKy1kyUXaOhL8WT50JiKrFM7iGm8VUHmdI/FLhkMmBJPz10cRNcs6UeHS4nTRGPGoPxrNCXOyg0lbHTdVAccTefhDNTh0iZWCbHT/pDEVoTeldTQFvtUI0BR0vIaTU2knKTVziN9NJkvuDco3PvqWqM0YVPkOJXHYfLwSuTUADxt9iImHDRSKZy3Ec2fnYnKGktXZTbdleqrlPzUBBX7ckO2WwFwtwOn3hcyjs2hTUlKc279usfcNnVLceJ5IQkrZzobzq3HbPGzz2IqJUiJG6MTNo+HAN4ON4pcamCAdHb+nWGKTBRlbp8+WAqmbHohnz3UBLkzjsJYYL2g== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 4/24/26 10:49 AM, Zi Yan wrote: > This check ensures the correctness of collapse read-only THPs for FSes > after READ_ONLY_THP_FOR_FS is enabled by default for all FSes supporting > PMD THP pagecache. > > READ_ONLY_THP_FOR_FS only supports read-only fd and uses mapping->nr_thps > and inode->i_writecount to prevent any write to read-only to-be-collapsed > folios. In upcoming commits, READ_ONLY_THP_FOR_FS will be removed and the > aforementioned mechanism will go away too. To ensure khugepaged functions > as expected after the changes, skip if any folio is dirty after > try_to_unmap(), since a dirty folio means this read-only folio > got some writes via mmap can happen between try_to_unmap() and > try_to_unmap_flush() via cached TLB entries and khugepaged does not support > writable pagecache folio collapse yet. > > Signed-off-by: Zi Yan > --- LGTM (Thanks to Lance for pointing out the xas lock issue in the previous version). Feel free to add: Reviewed-by: Baolin Wang