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DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=linux.dev; s=key1; t=1785871527; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=dVme6Lrk8eLALEVFcm4lB1EGIT/woVs12FA3T5p62Gk=; b=rCWUb/f0kE/YDFFqxsBddT28dRPKcKcZqwxdVfULUqxAts5R4l83/1wdpxno73X/EOlDRK oSfjTrBWMELU/htvG4Y4VYUGu0G2B2GxotUs5qW9VbSlXmdCwyG1OA2Z2oc7HsIBlGnszN EBN+yVvT6QPBVYbjB3l3TP4f6wYEZhA= From: "Nico Pache (Red Hat)" Date: Tue, 04 Aug 2026 13:25:00 -0600 Subject: [PATCH v3 2/7] mm/khugepaged: extract young page check into pte_is_referenced() helper MIME-Version: 1.0 Content-Type: text/plain; charset="utf-8" Content-Transfer-Encoding: 7bit Message-Id: <20260804-khugepaged_pte_refactor-v3-2-0364cad642a0@linux.dev> References: <20260804-khugepaged_pte_refactor-v3-0-0364cad642a0@linux.dev> In-Reply-To: <20260804-khugepaged_pte_refactor-v3-0-0364cad642a0@linux.dev> To: linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-doc@vger.kernel.org Cc: Andrew Morton , David Hildenbrand , Lorenzo Stoakes , Zi Yan , Baolin Wang , "Liam R. Howlett" , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan , "Nico Pache (Red Hat)" X-Migadu-Flow: FLOW_OUT X-Rspam-User: X-Rspamd-Server: rspam11 X-Rspamd-Queue-Id: 40767180008 X-Stat-Signature: wrn3gp7bgf44kefsxw6koxmbj5qmm4s8 X-HE-Tag: 1785871529-831551 X-HE-Meta: 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 lWKIJEFN D1rT4ImjZXBdxOd1cAstLuh32q9l68I6TWcxgS+Q1+rbXlyir/cC17JljsLgzSOow/GqTL0gRtCM6Ctzo8YqcKXVw7LyjmdldUg7HBA/e53B8sCEjJTPpwjcI+MLlaVySfEVc2J6YSBqhrQvuIgG8VIthY/a6z33rx6kKJ+OIBtkCC8PeSTMu/eJxstHvEntzrX2s+oSJm012MIVVeeYyALcqu9uD7hihGoG7kvu0hXbVSV5s/hqZpSrqA1V5bar4jL7B Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: This change deduplicates the "is this PTE/folio referenced enough to be considered for a collapse" condition that was repeated in both __collapse_huge_page_isolate() and collapse_scan_pmd(), extracting it into a single inline helper function. Also move the comment and use it as the function header. While we are at it, updated the comment to clarify that a young pte is a recently accessed one. Acked-by: Usama Arif Signed-off-by: Nico Pache (Red Hat) --- mm/khugepaged.c | 35 +++++++++++++++++++---------------- 1 file changed, 19 insertions(+), 16 deletions(-) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 1e26ea97381a..9b15c1740943 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -672,6 +672,23 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte, } } +/* + * pte_is_referenced() - Check for enough referenced PTEs to justify collapsing + * + * If collapse was initiated by khugepaged, check that the page has been + * recently accessed (young pte) to justify collapsing the page. + * + * Return: true if the page has been recently accessed. + */ +static inline bool pte_is_referenced(struct collapse_control *cc, pte_t pteval, + struct folio *folio, struct vm_area_struct *vma, unsigned long addr) +{ + return cc->is_khugepaged && + (pte_young(pteval) || folio_test_young(folio) || + folio_test_referenced(folio) || + mmu_notifier_test_young(vma->vm_mm, addr)); +} + static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma, unsigned long start_addr, pte_t *pte, struct collapse_control *cc, unsigned int order, struct list_head *compound_pagelist) @@ -810,14 +827,7 @@ static enum scan_result __collapse_huge_page_isolate(struct vm_area_struct *vma, if (folio_test_large(folio)) list_add_tail(&folio->lru, compound_pagelist); next: - /* - * If collapse was initiated by khugepaged, check that there is - * enough young pte to justify collapsing the page - */ - if (cc->is_khugepaged && - (pte_young(pteval) || folio_test_young(folio) || - folio_test_referenced(folio) || - mmu_notifier_test_young(vma->vm_mm, addr))) + if (pte_is_referenced(cc, pteval, folio, vma, addr)) referenced++; } @@ -1766,14 +1776,7 @@ static enum scan_result collapse_scan_pmd(struct mm_struct *mm, goto out_unmap; } - /* - * If collapse was initiated by khugepaged, check that there is - * enough young pte to justify collapsing the page - */ - if (cc->is_khugepaged && - (pte_young(pteval) || folio_test_young(folio) || - folio_test_referenced(folio) || - mmu_notifier_test_young(vma->vm_mm, addr))) + if (pte_is_referenced(cc, pteval, folio, vma, addr)) referenced++; } if (cc->is_khugepaged && -- 2.55.0