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h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=iEparMsGcO02O+o0tOuEdJ9CGG67+dAO90ssHctZ5f6vH9drv5WHMtg8RGsfYurCr HYjyTkZI62cLthPoG6x/jpOjNc2ekYXuQ1GS1fcYlTTa6cz84BHBrNAGnI11W/MxQy fDyhOmC5zVX9X81xgpqRslqHvf4Lbz3M27sSp3eo= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, hughd@google.com, chrisl@kernel.org Cc: ljs@kernel.org, Liam.Howlett@oracle.com, vbabka@kernel.org, rppt@kernel.org, surenb@google.com, mhocko@suse.com, kasong@tencent.com, qi.zheng@linux.dev, shakeel.butt@linux.dev, baohua@kernel.org, axelrasmussen@google.com, yuanchu@google.com, weixugc@google.com, riel@surriel.com, harry@kernel.org, jannh@google.com, pfalcato@suse.de, baolin.wang@linux.alibaba.com, shikemeng@huaweicloud.com, nphamcs@gmail.com, bhe@redhat.com, youngjun.park@lge.com, linux-mm@kvack.org, linux-kernel@vger.kernel.org, ryan.roberts@arm.com, anshuman.khandual@arm.com, Dev Jain Subject: [PATCH v2 5/9] mm/rmap: batch unmap folios belonging to uffd-wp VMAs Date: Fri, 10 Apr 2026 16:02:00 +0530 Message-Id: <20260410103204.120409-6-dev.jain@arm.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260410103204.120409-1-dev.jain@arm.com> References: <20260410103204.120409-1-dev.jain@arm.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 33778180010 X-Stat-Signature: ohjcz963iiguk1ga18wx1w73o6su8c4b X-HE-Tag: 1775817185-302678 X-HE-Meta: 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 Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: Commit a67fe41e214f ("mm: rmap: support batched unmapping for file large folios") extended batched unmapping for file folios. That also required making install_uffd_wp_ptes_if_needed() support batching, but that was left out for the time being, and correctness was maintained by stopping batching in case the VMA the folio belongs to is marked uffd-wp. Now that we have a batched version called install_uffd_wp_ptes_if_needed, simply call that. folio_unmap_pte_batch() ensures that the original state of the ptes is either all uffd or all non-uffd, so we maintain correctness. If uffd-wp bit is there, we have the following transitions of ptes after unmapping: 1) anon folio: present -> uffd-wp swap 2) file folio: present -> uffd-wp marker We must ensure that these ptes are not reprocessed by the while loop - if the batch length is less than the number of pages in the folio, then we must skip over this batch. The page_vma_mapped_walk API ensures this - check_pte() will return true only if any of [pvmw->pfn, pvmw->pfn + nr_pages) is mapped by the pte. There is no pfn underlying either a uffd-wp swap pte or a uffd-wp marker pte, so check_pte returns false and we keep skipping until we hit a present entry, which is where we want to batch from next. Signed-off-by: Dev Jain --- mm/rmap.c | 5 +---- 1 file changed, 1 insertion(+), 4 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 20e1fb81c33fc..7a150edd96819 100644 --- a/mm/rmap.c +++ b/mm/rmap.c @@ -1965,9 +1965,6 @@ static inline unsigned int folio_unmap_pte_batch(struct folio *folio, if (pte_unused(pte)) return 1; - if (userfaultfd_wp(vma)) - return 1; - /* * If unmap fails, we need to restore the ptes. To avoid accidentally * upgrading write permissions for ptes that were not originally @@ -2263,7 +2260,7 @@ static bool try_to_unmap_one(struct folio *folio, struct vm_area_struct *vma, * we may want to replace a none pte with a marker pte if * it's file-backed, so we don't lose the tracking info. */ - install_uffd_wp_ptes_if_needed(vma, address, pvmw.pte, pteval, 1); + install_uffd_wp_ptes_if_needed(vma, address, pvmw.pte, pteval, nr_pages); /* Update high watermark before we lower rss */ update_hiwater_rss(mm); -- 2.34.1