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client-ip=165.204.84.17; helo=satlexmb07.amd.com; pr=C Received: from satlexmb07.amd.com (165.204.84.17) by MWH0EPF000971E3.mail.protection.outlook.com (10.167.243.70) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.20.9564.3 via Frontend Transport; Thu, 29 Jan 2026 14:42:11 +0000 Received: from BLR-L-BHARARAO.amd.com (10.180.168.240) by satlexmb07.amd.com (10.181.42.216) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id 15.2.2562.17; Thu, 29 Jan 2026 08:42:00 -0600 From: Bharata B Rao To: , CC: , , , , , , , , , , , , , , , , , , , , , , , , , , , Bharata B Rao Subject: [RFC PATCH v5 02/10] migrate: Add migrate_misplaced_folios_batch() Date: Thu, 29 Jan 2026 20:10:35 +0530 Message-ID: <20260129144043.231636-3-bharata@amd.com> X-Mailer: git-send-email 2.34.1 In-Reply-To: <20260129144043.231636-1-bharata@amd.com> References: <20260129144043.231636-1-bharata@amd.com> Precedence: bulk X-Mailing-List: linux-kernel@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: MIME-Version: 1.0 Content-Transfer-Encoding: quoted-printable X-ClientProxiedBy: satlexmb08.amd.com (10.181.42.217) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: MWH0EPF000971E3:EE_|MN2PR12MB4488:EE_ X-MS-Office365-Filtering-Correlation-Id: 7458435f-10da-47c1-c673-08de5f449648 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|376014|7416014|36860700013|82310400026|1800799024; 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X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 29 Jan 2026 14:42:11.5615 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 7458435f-10da-47c1-c673-08de5f449648 X-MS-Exchange-CrossTenant-Id: 3dd8961f-e488-4e60-8e11-a82d994e183d X-MS-Exchange-CrossTenant-OriginalAttributedTenantConnectingIp: TenantId=3dd8961f-e488-4e60-8e11-a82d994e183d;Ip=[165.204.84.17];Helo=[satlexmb07.amd.com] X-MS-Exchange-CrossTenant-AuthSource: MWH0EPF000971E3.namprd02.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: MN2PR12MB4488 Content-Type: text/plain; charset="utf-8" From: Gregory Price Tiered memory systems often require migrating multiple folios at once. Currently, migrate_misplaced_folio() handles only one folio per call, which is inefficient for batch operations. This patch introduces migrate_misplaced_folios_batch(), a batch variant that leverages migrate_pages() internally for improved performance. The caller must isolate folios beforehand using migrate_misplaced_folio_prepare(). On return, the folio list will be empty regardless of success or failure. This function will be used by pghot kmigrated thread. Signed-off-by: Gregory Price [Rewrote commit description] Signed-off-by: Bharata B Rao --- include/linux/migrate.h | 6 ++++++ mm/migrate.c | 36 ++++++++++++++++++++++++++++++++++++ 2 files changed, 42 insertions(+) diff --git a/include/linux/migrate.h b/include/linux/migrate.h index 26ca00c325d9..f28326b88592 100644 --- a/include/linux/migrate.h +++ b/include/linux/migrate.h @@ -103,6 +103,7 @@ static inline int set_movable_ops(const struct movable_= operations *ops, enum pag int migrate_misplaced_folio_prepare(struct folio *folio, struct vm_area_struct *vma, int node); int migrate_misplaced_folio(struct folio *folio, int node); +int migrate_misplaced_folios_batch(struct list_head *folio_list, int node); #else static inline int migrate_misplaced_folio_prepare(struct folio *folio, struct vm_area_struct *vma, int node) @@ -113,6 +114,11 @@ static inline int migrate_misplaced_folio(struct folio= *folio, int node) { return -EAGAIN; /* can't migrate now */ } +static inline int migrate_misplaced_folios_batch(struct list_head *folio_l= ist, + int node) +{ + return -EAGAIN; /* can't migrate now */ +} #endif /* CONFIG_NUMA_BALANCING */ =20 #ifdef CONFIG_MIGRATION diff --git a/mm/migrate.c b/mm/migrate.c index 70f8f3ad4fd8..4a3a9a4ff435 100644 --- a/mm/migrate.c +++ b/mm/migrate.c @@ -2747,5 +2747,41 @@ int migrate_misplaced_folio(struct folio *folio, int= node) BUG_ON(!list_empty(&migratepages)); return nr_remaining ? -EAGAIN : 0; } + +/** + * migrate_misplaced_folios_batch() - Batch variant of migrate_misplaced_f= olio. + * Attempts to migrate a folio list to the specified destination. + * @folio_list: Isolated list of folios to be batch-migrated. + * @node: The NUMA node ID to where the folios should be migrated. + * + * Caller is expected to have isolated the folios by calling + * migrate_misplaced_folio_prepare(), which will result in an + * elevated reference count on the folio. + * + * This function will un-isolate the folios, drop the elevated reference + * and remove them from the list before returning. + * + * Return: 0 on success and -EAGAIN on failure or partial migration. + * On return, @folio_list will be empty regardless of success/fail= ure. + */ +int migrate_misplaced_folios_batch(struct list_head *folio_list, int node) +{ + pg_data_t *pgdat =3D NODE_DATA(node); + unsigned int nr_succeeded =3D 0; + int nr_remaining; + + nr_remaining =3D migrate_pages(folio_list, alloc_misplaced_dst_folio, + NULL, node, MIGRATE_ASYNC, + MR_NUMA_MISPLACED, &nr_succeeded); + if (nr_remaining) + putback_movable_pages(folio_list); + + if (nr_succeeded) { + count_vm_numa_events(NUMA_PAGE_MIGRATE, nr_succeeded); + mod_node_page_state(pgdat, PGPROMOTE_SUCCESS, nr_succeeded); + } + WARN_ON(!list_empty(folio_list)); + return nr_remaining ? -EAGAIN : 0; +} #endif /* CONFIG_NUMA_BALANCING */ #endif /* CONFIG_NUMA */ --=20 2.34.1