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Howlett" , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , Usama Arif , Vlastimil Babka , Mike Rapoport , Suren Baghdasaryan , Michal Hocko , Jonathan Corbet , Shuah Khan Subject: Re: [PATCH v4 2/7] mm/khugepaged: extract reference check into folio_pte_referenced() helper Message-ID: References: <20260811-khugepaged_pte_refactor-v4-0-ddac39d61c4a@linux.dev> <20260811-khugepaged_pte_refactor-v4-2-ddac39d61c4a@linux.dev> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20260811-khugepaged_pte_refactor-v4-2-ddac39d61c4a@linux.dev> X-Rspamd-Queue-Id: D730240004 X-Rspam-User: X-Stat-Signature: x7k9ioheij8x4s3rzbk39k5wy5cr6onz X-Rspamd-Server: rspam06 X-HE-Tag: 1786966398-813486 X-HE-Meta: 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 EcPF5kRE 5M2URxsF2uTghv8Ep08S8ZFRt+7ej7lguFgDSvWJ67TgHB7PtC6fz5yz5dJDfUhrS1LprHAhq0mCVI8uGHJpYgFl3b2/fAbguIqsAOorW/solHiiSzBYqCbMpQXvHN3PghC6DK6QC/GaV2VX29KL4myb9iSt0mUolyUv5rLXqvvy3VPFza7oooU1h3E3c8Nn9kN5ojnafKcYQ/zfZ8/kj8r6p8YOFvAcI7RoKPKhzyYOJsH9wWXSxJlMxrlhElsiag9cI1M8sxcU7Cs0ze+uWjmEy/+25d7V49wqkrXphggQJcKWZfcF93HbmV91XO/0IfX7/ Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On Tue, Aug 11, 2026 at 06:48:34AM -0600, Nico Pache (Red Hat) wrote: > 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) With below addressed nice cleanup so: Reviewed-by: Lorenzo Stoakes (ARM) > --- > mm/khugepaged.c | 32 ++++++++++++++++++-------------- > 1 file changed, 18 insertions(+), 14 deletions(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 1e26ea97381a..8babd4c97db6 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -672,6 +672,22 @@ static void release_pte_pages(pte_t *pte, pte_t *_pte, > } > } > > +/* > + * folio_pte_referenced() - Check if a folio or its PTE mapping was recently used > + * > + * Return: true if recent access was observed through either the folio state > + * or the current PTE mapping. > + */ As discussed please drop :) > +static inline bool folio_pte_referenced(struct folio *folio, Please remove inline, for any sane compiler (i.e. any we reasonably support) this makes no difference for a static function within a compilation unit. > + struct vm_area_struct *vma, unsigned long addr, pte_t pteval) > +{ > + /* The folio was referenced previously ... */ > + if (folio_test_young(folio) || folio_test_referenced(folio)) > + return true; > + /* ... or the PTE mapping was recently used */ > + return pte_young(pteval) || 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 +826,8 @@ 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))) > + folio_pte_referenced(folio, vma, addr, pteval)) > referenced++; > } > > @@ -1766,14 +1776,8 @@ 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))) > + folio_pte_referenced(folio, vma, addr, pteval)) > referenced++; > } > if (cc->is_khugepaged && > > -- > 2.55.0 > -- Cheers, Lorenzo