From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from foss.arm.com (foss.arm.com [217.140.110.172]) by smtp.subspace.kernel.org (Postfix) with ESMTP id ED1D73164C5 for ; Wed, 15 Jul 2026 11:19:12 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=217.140.110.172 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784114354; cv=none; b=oI+RXk9x3OSyt6mDTCOTM2vLQG1ei1mcc3G3vl9mxkekQ5rJdCTB8oZSfe4/zQY/vIq2n5lqRzybtbSYJzQ2DjyDJu3adtuqeBcV1Sl4F9M+6t/6oWwfStzM96BXKQMhtWqBr5g3lO2CKkihl8lQ+z38HW3fP5i8VE2Q0hs9R74= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1784114354; c=relaxed/simple; bh=+o9DpSGseXucY8pTcFbS+W9IBHMvf3AT4jdAayQBJ8o=; h=From:To:Cc:Subject:Date:Message-ID:In-Reply-To:References: MIME-Version; b=SwYrWrposq4Um68YDhax3i3bVlOZ1/586hiSyIY3/ohUdY//EUXLBapT8MCm8sxdAIadD9QJ/NJ1gtH7/LxR6fuSsoHyRJb6fVFp+LWbxc5vR04bwA2KVY5k/+3yxy4xLzsJi/gLSCLztxNZTW2EpZJY81lm2fQZNILIeSMTpDA= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com; spf=pass smtp.mailfrom=arm.com; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b=cMFHUiae; arc=none smtp.client-ip=217.140.110.172 Authentication-Results: smtp.subspace.kernel.org; dmarc=pass (p=none dis=none) header.from=arm.com Authentication-Results: smtp.subspace.kernel.org; spf=pass smtp.mailfrom=arm.com Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=arm.com header.i=@arm.com header.b="cMFHUiae" Received: from usa-sjc-imap-foss1.foss.arm.com (unknown [10.121.207.14]) by usa-sjc-mx-foss1.foss.arm.com (Postfix) with ESMTP id B9139153B; Wed, 15 Jul 2026 04:19:07 -0700 (PDT) Received: from cesw-amp-gbt-1s-m12830-01.blr.arm.com (cesw-amp-gbt-1s-m12830-01.blr.arm.com [10.164.195.33]) by usa-sjc-imap-foss1.foss.arm.com (Postfix) with ESMTPA id EBA483F915; Wed, 15 Jul 2026 04:19:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=simple/simple; d=arm.com; s=foss; t=1784114352; bh=+o9DpSGseXucY8pTcFbS+W9IBHMvf3AT4jdAayQBJ8o=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=cMFHUiaeqiLmMlN8BYlKnh6OjgLR9tKyb3ltisY+8hUHTgVbih7101lm/gflcV05s aK+QLl9e+84ArIvxO/iHsUkLoj8mfp9CmE7xTuFSSUpzMRuCkkprSSvhYSYcCuxIMl yoBAn5gFAkv7F+upQWY0lmCysJeHP6wuXfi+kueM= From: Dev Jain To: akpm@linux-foundation.org, david@kernel.org, ljs@kernel.org Cc: Dev Jain , liam@infradead.org, 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, linux-mm@kvack.org, linux-kernel@vger.kernel.org, riel@surriel.com, harry@kernel.org, jannh@google.com, lance.yang@linux.dev, ryan.roberts@arm.com, anshuman.khandual@arm.com Subject: [PATCH 3/3] mm/rmap: batch unmap file folios belonging to uffd-wp VMAs Date: Wed, 15 Jul 2026 11:18:36 +0000 Message-ID: <20260715111839.1667914-4-dev.jain@arm.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260715111839.1667914-1-dev.jain@arm.com> References: <20260715111839.1667914-1-dev.jain@arm.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Commit a67fe41e214f ("mm: rmap: support batched unmapping for file large folios") extended batched unmapping for file folios. That also required making install_uffd_wp_pte_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 cond_install_uffd_wp_ptes, 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, for a 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 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. Note that for the uffd-rwp case, we already do not make a uffd marker in cond_install_uffd_wp_ptes. Signed-off-by: Dev Jain --- Dropped David's ACK due to the uffd-rwp changes. mm/rmap.c | 6 ++---- 1 file changed, 2 insertions(+), 4 deletions(-) diff --git a/mm/rmap.c b/mm/rmap.c index 2f938d0ac6953..ac88673600fa0 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_protected(vma)) - return 1; - /* * If unmap fails, we need to restore the ptes. To avoid accidentally * upgrading write permissions for ptes that were not originally @@ -2345,7 +2342,8 @@ 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. */ - cond_install_uffd_wp_ptes(vma, address, pvmw.pte, pteval, 1); + cond_install_uffd_wp_ptes(vma, address, pvmw.pte, pteval, + nr_pages); /* Update high watermark before we lower rss */ update_hiwater_rss(mm); -- 2.43.0