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charset=UTF-8 Date: Sat, 03 Oct 2026 22:11:32 -0400 Message-Id: From: "Zi Yan" Subject: Re: [PATCH RFC v3 15/17] mm/khugepaged: check folio referenced state via LRU refs under MGLRU Cc: "Andrew Morton" , "Johannes Weiner" , "Muchun Song" , "Qi Zheng" , "Ying Huang" , "Chris Li" , "Baoquan He" , "Nico Pache" , "Usama Arif" , "Michal Hocko" , "Roman Gushchin" , "Shakeel Butt" , "David Hildenbrand" , "Lorenzo Stoakes" , "Barry Song" , "Axel Rasmussen" , "Yuanchu Xie" , "Wei Xu" , "Vlastimil Babka" , "Suren Baghdasaryan" , "Kemeng Shi" , "Nhat Pham" , "Youngjun Park" , "Gregory Price" , "Matthew Wilcox (Oracle)" , "Baolin Wang" , "Ryan Roberts" , "Dev Jain" , "Lance Yang" , "Hugh Dickins" , "SeongJae Park" , "David Rientjes" , "Yu Zhao" , "Vernon Yang" , "Zicheng Wang" , "Chen Ridong" , "Tal Zussman" , "Kairui Song" , "Xiang Liu" , "Ehab Ababneh" , "zhaozhengzhuo" , "Lian Wang" , "Kunwu Chan" , , To: , X-Mailer: aerc 0.22.0 References: <20261003-mglru-fg-v3-0-cbd4546a5bd9@tencent.com> <20261003-mglru-fg-v3-15-cbd4546a5bd9@tencent.com> In-Reply-To: <20261003-mglru-fg-v3-15-cbd4546a5bd9@tencent.com> X-ClientProxiedBy: BL1PR13CA0004.namprd13.prod.outlook.com (2603:10b6:208:256::9) To IA0PR12MB8374.namprd12.prod.outlook.com (2603:10b6:208:40e::7) Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: IA0PR12MB8374:EE_|CHAPR12MB999224:EE_ X-MS-Office365-Filtering-Correlation-Id: 6bdcb519-f726-4cd4-be29-08df21bcd042 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|366016|23010399003|1800799024|7416014|376014|10067099003|56012099006|4143699003|11063799006|6133799003|22082099003|18002099003; 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The classical LRU keeps the plain bit test. Why not reuse the smaps helper function? You can rename the helper to check_folio_referenced() for general use. > > Signed-off-by: Kairui Song > --- > mm/khugepaged.c | 4 +++- > 1 file changed, 3 insertions(+), 1 deletion(-) > > diff --git a/mm/khugepaged.c b/mm/khugepaged.c > index 913086eaf17b..be18381c6efd 100644 > --- a/mm/khugepaged.c > +++ b/mm/khugepaged.c > @@ -586,7 +586,9 @@ static bool folio_pte_referenced(struct folio *folio, > 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)) > + if (folio_test_young(folio)) > + return true; > + if (lru_gen_enabled() ? folio_lru_refs(folio) : folio_test_referenced(f= olio)) > return true; > /* ... or the PTE mapping was recently used */ > return pte_young(pteval) || mmu_notifier_test_young(vma->vm_mm, addr); --=20 Best Regards, Yan, Zi