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Howlett" , "Nico Pache" , "Ryan Roberts" , "Dev Jain" , "Barry Song" , "Lance Yang" , "Usama Arif" , "Vlastimil Babka" , "Jann Horn" , "Kiryl Shutsemau (Meta)" To: "Kiryl Shutsemau" , "Andrew Morton" , "David Hildenbrand" , "Lorenzo Stoakes" From: "Zi Yan" Subject: Re: [PATCH 04/12] mm/collapse: add collapse.h for the collapse interface X-Mailer: aerc 0.22.0 References: In-Reply-To: X-ClientProxiedBy: BLAPR03CA0178.namprd03.prod.outlook.com (2603:10b6:208:32f::32) 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_|CH3PR12MB8185:EE_ X-MS-Office365-Filtering-Correlation-Id: 7c21f18a-251c-4767-cddb-08df0af68f81 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|23010399003|376014|7416014|1800799024|366016|11063799006|10067099003|4143699003|5023799004|22082099003|18002099003|56012099006; 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The daemon's scan loop, the sysfs tunables, MADV_COLLAPSE's > entry point and the collapse itself all sit in one file and reach into > each other freely. Nothing marks where a user ends and the engine > begins. > > Start drawing that line. > > Add mm/collapse.h for what the two sides have to agree on: > > - enum scan_result - what the engine hands back; > - struct collapse_control - the state a request carries. > > And two constants move with them: > > - KHUGEPAGED_MAX_PTES_LIMIT -> COLLAPSE_MAX_PTES_LIMIT; > - KHUGEPAGED_MIN_MTHP_ORDER -> COLLAPSE_MIN_MTHP_ORDER. > > Neither is a fact about the daemon, so both lose the KHUGEPAGED_ prefix. > > No functional change. > > Assisted-by: Claude-Code:claude-opus-5 > Signed-off-by: Kiryl Shutsemau (Meta) > --- > MAINTAINERS | 1 + > mm/collapse.h | 67 +++++++++++++++++++++++++++++++++++++++++ > mm/khugepaged.c | 79 ++++++++----------------------------------------- > 3 files changed, 81 insertions(+), 66 deletions(-) > create mode 100644 mm/collapse.h > > + > +enum scan_result { > + SCAN_FAIL, > + SCAN_SUCCEED, > + SCAN_NO_PTE_TABLE, > + SCAN_PMD_MAPPED, > + SCAN_EXCEED_NONE_PTE, > + SCAN_EXCEED_SWAP_PTE, > + SCAN_EXCEED_SHARED_PTE, > + SCAN_PTE_NON_PRESENT, > + SCAN_PTE_UFFD, > + SCAN_PTE_MAPPED_HUGEPAGE, > + SCAN_LACK_REFERENCED_PAGE, > + SCAN_PAGE_NULL, > + SCAN_SCAN_ABORT, > + SCAN_PAGE_COUNT, > + SCAN_PAGE_LRU, > + SCAN_PAGE_LOCK, > + SCAN_PAGE_ANON, > + SCAN_PAGE_LAZYFREE, > + SCAN_PAGE_COMPOUND, > + SCAN_ANY_PROCESS, > + SCAN_VMA_NULL, > + SCAN_VMA_CHECK, > + SCAN_ADDRESS_RANGE, > + SCAN_DEL_PAGE_LRU, > + SCAN_ALLOC_HUGE_PAGE_FAIL, > + SCAN_CGROUP_CHARGE_FAIL, > + SCAN_TRUNCATED, > + SCAN_PAGE_HAS_PRIVATE, > + SCAN_STORE_FAILED, > + SCAN_COPY_MC, > + SCAN_PAGE_FILLED, > + SCAN_PAGE_DIRTY_OR_WRITEBACK, > +}; Are you planning to clean up scan_result? SCAN_SCAN_ABORT sounds funny, SCAN_ANY_PROCESS means nothing, SCAN_COPY_MC might better be COLLAPSE_COPY_MC. Anyway, for this patch, Reviewed-by: Zi Yan --=20 Best Regards, Yan, Zi