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Howlett" , Nico Pache , Ryan Roberts , Dev Jain , Barry Song , Lance Yang , , , Subject: [PATCH V3 3/5] mm/khugepaged: change collapse_pte_mapped_thp() to return void Date: Sun, 18 Jan 2026 19:22:57 +0000 Message-ID: <20260118192253.9263-10-shivankg@amd.com> X-Mailer: git-send-email 2.43.0 In-Reply-To: <20260118192253.9263-4-shivankg@amd.com> References: <20260118192253.9263-4-shivankg@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: satlexmb07.amd.com (10.181.42.216) To satlexmb07.amd.com (10.181.42.216) X-EOPAttributedMessage: 0 X-MS-PublicTrafficType: Email X-MS-TrafficTypeDiagnostic: CY4PEPF0000FCC2:EE_|BY5PR12MB4036:EE_ X-MS-Office365-Filtering-Correlation-Id: 209ec9a7-981c-4959-f59c-08de56c7c2b1 X-MS-Exchange-SenderADCheck: 1 X-MS-Exchange-AntiSpam-Relay: 0 X-Microsoft-Antispam: BCL:0;ARA:13230040|82310400026|7416014|376014|1800799024|36860700013; X-Microsoft-Antispam-Message-Info: =?us-ascii?Q?dMdc3+lKIw3Ru/SlIHGKkJvgGYGzZNp0JX8BW1fZ5PN/Af6q3Q0MvFjcKzlM?= =?us-ascii?Q?5pcD1zgQMZtTw7Iy4K4EkxwFV5AsGFo64K+yOoLRM6RpyMvMZ4eelsQ/CDnB?= =?us-ascii?Q?GOBKQvfx8+osoebJYvdjCgNbu8Y/u7yJBKBaF2N92Gmt/n1UDhU4mG+S8v3C?= =?us-ascii?Q?1xu7QZ5/uA4KDIB790vSv94bHCnmt3oM4GhczfKr8yxv7JA3ii8FnSB4Yv9n?= =?us-ascii?Q?kFZDQwOCzU4TkvbrpNJklhK6YPJ6TYXt0QQ/7SBfvZAy+UBpkrUSp5RDvAf2?= =?us-ascii?Q?W+nnRMy02mAXpksnMuYoGWd8AjYKXgrdPoRbBPc8iMEpjFEhhHZUNABM1JlK?= =?us-ascii?Q?FWoAUxHj/OepWAypy/BfnLL23ZWPEcs7vq1epBoqrGuBbJHR80s1YoWL6BZO?= =?us-ascii?Q?Lew857hhuacUz/dtIFI/95FdE32lez69ZJdgK1pruJVVGvF6EKKvjypLbKuP?= =?us-ascii?Q?0m9EuOuZeob9BulQ/y2ocpPnCw0dKVE/fujXKJan0ZbUYULAC8Co5q6PsMik?= =?us-ascii?Q?x0NZ3zoHzOaffIFwvPDX7TRiNG+8z6G8M6WCDyGzmBC8twB33Y5Tdg7HL3M3?= =?us-ascii?Q?HN24tncHEje8EFSOg8mELhaCGRrACPrP/WfAY7O405v+mnHmzAMdMCfy3pyL?= =?us-ascii?Q?eaMZOdgg8gaODunKmq/MjxnrnZAoYyVHg+lsVNcBYmPd4ogQ6PfR6aUt9k5v?= =?us-ascii?Q?GZ7Q6MCPecJt/AjsO0M3v6gE/y8YTeSbKay/YmBzdAAcywxTKgO2u93DCyPe?= =?us-ascii?Q?eUqxvYhufo47L1cfKHK2TnMR9K8M/13fnBz2wQBzyZg//ce85jNBQYkck1UM?= =?us-ascii?Q?tyQ4RoPTcQ5TEJm5d2tX9i8vsQMefpo+DfA6Vp7v5/E+GzkEvdfCqb/LTYSr?= =?us-ascii?Q?TJNv2rw3YW66/BE+q+8JL5BcAlBHnnwWUbvDZDKIdrAb5X0cKGJD5EAT73Cm?= =?us-ascii?Q?kq3uT/KATDXET20wA1d21fWeyIbh/OTLB0F8cTRZ49E0hBpQNF+PMAQvHPKG?= =?us-ascii?Q?PswcGuWMElySCKVk899LJ8WnM5kyHN7Huvea/CUln0EnfWCPCUQmCP01VMX+?= =?us-ascii?Q?yTIhbz5LBr7qGUJx7BE8DRwAjzR6UUtcrX7l5zQukrQ/n82vkgXnSi+cbWVT?= =?us-ascii?Q?SR7W5ajwJzMRv6/Kq+qEPMTSB3VxUotp+vses7rEFqUpHWvaCqcZgte7PbrD?= =?us-ascii?Q?UtYI+nvZ95Tpx/hTEwbj9BYKnGrsaI5cWZqov8A1VWF0WFwgFRSmALEFHFJX?= =?us-ascii?Q?HYuQYfUReEeeV4FK8Fj0FUb3j3Bye9+aBOv32ojk5n8EhpYyMIoAmT7d9qLx?= =?us-ascii?Q?1ua1c43x1j57GupX5wtsFKfxfNoPR5v8D6H4j/Wof3Zeq2S9+1Z3rN2Yxugg?= =?us-ascii?Q?YGWJVoCUtNFYmY+eSFtDkzHbaazOcLVaxBHyqW2B5knKu8xzC9jJQ2FBEWmO?= =?us-ascii?Q?+p7HaCQasSoYxKyD18zmP9jFyGMUr4WpPmESAHu9tekoyPz7UHbDwzZ1Kn/I?= =?us-ascii?Q?1JdLZr9aF3p8HdxwIXAFjzwrRh8SnPzwDMRM4j13r2a5TYDb7Q6JqUpCqN7L?= =?us-ascii?Q?IhA0Dfe1QjKVhccbPyBdapFEcz7WMpU2eGFcLH4kiqVXuZkAX1x/s7wXVrs+?= =?us-ascii?Q?OSp5+iDwyop8tsMfqPFqwgUWX2t2DuwOQYlxDJCz+juv?= X-Forefront-Antispam-Report: CIP:165.204.84.17;CTRY:US;LANG:en;SCL:1;SRV:;IPV:NLI;SFV:NSPM;H:satlexmb07.amd.com;PTR:InfoDomainNonexistent;CAT:NONE;SFS:(13230040)(82310400026)(7416014)(376014)(1800799024)(36860700013);DIR:OUT;SFP:1101; X-OriginatorOrg: amd.com X-MS-Exchange-CrossTenant-OriginalArrivalTime: 18 Jan 2026 19:28:29.7252 (UTC) X-MS-Exchange-CrossTenant-Network-Message-Id: 209ec9a7-981c-4959-f59c-08de56c7c2b1 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: CY4PEPF0000FCC2.namprd03.prod.outlook.com X-MS-Exchange-CrossTenant-AuthAs: Anonymous X-MS-Exchange-CrossTenant-FromEntityHeader: HybridOnPrem X-MS-Exchange-Transport-CrossTenantHeadersStamped: BY5PR12MB4036 Content-Type: text/plain; charset="utf-8" The only external caller of collapse_pte_mapped_thp() is uprobe, which ignores the return value. Change the external API to return void to simplify the interface. Introduce try_collapse_pte_mapped_thp() for internal use that preserves the return value. This prepares for future patch that will convert the return type to use enum scan_result. Suggested-by: David Hildenbrand (Red Hat) Acked-by: Lance Yang Acked-by: David Hildenbrand (Red Hat) Reviewed-by: Zi Yan Signed-off-by: Shivank Garg Reviewed-by: Nico Pache Tested-by: Nico Pache --- include/linux/khugepaged.h | 9 ++++----- mm/khugepaged.c | 40 ++++++++++++++++++++++---------------- 2 files changed, 27 insertions(+), 22 deletions(-) diff --git a/include/linux/khugepaged.h b/include/linux/khugepaged.h index eb1946a70cff..d7a9053ff4fe 100644 --- a/include/linux/khugepaged.h +++ b/include/linux/khugepaged.h @@ -17,8 +17,8 @@ extern void khugepaged_enter_vma(struct vm_area_struct *v= ma, vm_flags_t vm_flags); extern void khugepaged_min_free_kbytes_update(void); extern bool current_is_khugepaged(void); -extern int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long add= r, - bool install_pmd); +void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr, + bool install_pmd); =20 static inline void khugepaged_fork(struct mm_struct *mm, struct mm_struct = *oldmm) { @@ -42,10 +42,9 @@ static inline void khugepaged_enter_vma(struct vm_area_s= truct *vma, vm_flags_t vm_flags) { } -static inline int collapse_pte_mapped_thp(struct mm_struct *mm, - unsigned long addr, bool install_pmd) +static inline void collapse_pte_mapped_thp(struct mm_struct *mm, + unsigned long addr, bool install_pmd) { - return 0; } =20 static inline void khugepaged_min_free_kbytes_update(void) diff --git a/mm/khugepaged.c b/mm/khugepaged.c index 93ce39915f4a..17f3f0043368 100644 --- a/mm/khugepaged.c +++ b/mm/khugepaged.c @@ -1477,20 +1477,8 @@ static int set_huge_pmd(struct vm_area_struct *vma, = unsigned long addr, return SCAN_SUCCEED; } =20 -/** - * collapse_pte_mapped_thp - Try to collapse a pte-mapped THP for mm at - * address haddr. - * - * @mm: process address space where collapse happens - * @addr: THP collapse address - * @install_pmd: If a huge PMD should be installed - * - * This function checks whether all the PTEs in the PMD are pointing to the - * right THP. If so, retract the page table so the THP can refault in with - * as pmd-mapped. Possibly install a huge PMD mapping the THP. - */ -int collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr, - bool install_pmd) +static int try_collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long= addr, + bool install_pmd) { int nr_mapped_ptes =3D 0, result =3D SCAN_FAIL; unsigned int nr_batch_ptes; @@ -1711,6 +1699,24 @@ int collapse_pte_mapped_thp(struct mm_struct *mm, un= signed long addr, return result; } =20 +/** + * collapse_pte_mapped_thp - Try to collapse a pte-mapped THP for mm at + * address haddr. + * + * @mm: process address space where collapse happens + * @addr: THP collapse address + * @install_pmd: If a huge PMD should be installed + * + * This function checks whether all the PTEs in the PMD are pointing to the + * right THP. If so, retract the page table so the THP can refault in with + * as pmd-mapped. Possibly install a huge PMD mapping the THP. + */ +void collapse_pte_mapped_thp(struct mm_struct *mm, unsigned long addr, + bool install_pmd) +{ + try_collapse_pte_mapped_thp(mm, addr, install_pmd); +} + /* Can we retract page tables for this file-backed VMA? */ static bool file_backed_vma_is_retractable(struct vm_area_struct *vma) { @@ -2227,7 +2233,7 @@ static int collapse_file(struct mm_struct *mm, unsign= ed long addr, =20 /* * Remove pte page tables, so we can re-fault the page as huge. - * If MADV_COLLAPSE, adjust result to call collapse_pte_mapped_thp(). + * If MADV_COLLAPSE, adjust result to call try_collapse_pte_mapped_thp(). */ retract_page_tables(mapping, start); if (cc && !cc->is_khugepaged) @@ -2480,7 +2486,7 @@ static unsigned int khugepaged_scan_mm_slot(unsigned = int pages, int *result, mmap_read_lock(mm); if (hpage_collapse_test_exit_or_disable(mm)) goto breakouterloop; - *result =3D collapse_pte_mapped_thp(mm, + *result =3D try_collapse_pte_mapped_thp(mm, khugepaged_scan.address, false); if (*result =3D=3D SCAN_PMD_MAPPED) *result =3D SCAN_SUCCEED; @@ -2845,7 +2851,7 @@ int madvise_collapse(struct vm_area_struct *vma, unsi= gned long start, case SCAN_PTE_MAPPED_HUGEPAGE: BUG_ON(mmap_locked); mmap_read_lock(mm); - result =3D collapse_pte_mapped_thp(mm, addr, true); + result =3D try_collapse_pte_mapped_thp(mm, addr, true); mmap_read_unlock(mm); goto handle_result; /* Whitelisted set of results where continuing OK */ --=20 2.43.0