From: Gerald Schaefer Date: Mon, 30 Jun 2025 16:47:25 +0000 (+0200) Subject: mm/debug_vm_pgtable: use a swp_entry_t input value for swap tests X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=c26ad45ba538434e87290c7db5a93fe11263f593;p=thirdparty%2Flinux.git mm/debug_vm_pgtable: use a swp_entry_t input value for swap tests The various __pte/pmd_to_swp_entry and __swp_entry_to_pte/pmd helper functions are expected to operate on swap PTE/PMD entries, not on present and mapped entries. Reflect this in the swap tests by using a swp_entry_t as input value, and convert it to a swap PTE/PMD for testing, similar to how it is already done in pte_swap_exclusive_tests(). Move the swap entry creation from there to init_args() and store it in args, so it can also be used in other functions. The pte/pmd_swap_tests() are also changed to compare entries instead of pfn values, again similar to pte_swap_exclusive_tests(). pte/pmd_pfn() helpers are also not expected to operate on swap PTE/PMD entries at all. Also update documentation, to reflect that the helpers operate on swap PTE/PMD entries and not present and mapped entries, and use correct names, i.e. __swp_to_pte/pmd_entry -> __swp_entry_to_pte/pmd. For consistency, also change pte/pmd_swap_soft_dirty_tests() to use args->swp_entry instead of a present and mapped PTE/PMD. Link: https://lore.kernel.org/all/20250623184321.927418-1-gerald.schaefer@linux.ibm.com Link: https://lkml.kernel.org/r/20250630164726.930405-1-gerald.schaefer@linux.ibm.com Signed-off-by: Gerald Schaefer Acked-by: David Hildenbrand Reviewed-by: Anshuman Khandual Cc: Matthew Wilcox (Oracle) Signed-off-by: Andrew Morton --- diff --git a/Documentation/mm/arch_pgtable_helpers.rst b/Documentation/mm/arch_pgtable_helpers.rst index c88c7fa665d67..ba2f658bc241a 100644 --- a/Documentation/mm/arch_pgtable_helpers.rst +++ b/Documentation/mm/arch_pgtable_helpers.rst @@ -236,13 +236,13 @@ SWAP Page Table Helpers ======================== +---------------------------+--------------------------------------------------+ -| __pte_to_swp_entry | Creates a swapped entry (arch) from a mapped PTE | +| __pte_to_swp_entry | Creates a swp_entry_t (arch) from a swap PTE | +---------------------------+--------------------------------------------------+ -| __swp_to_pte_entry | Creates a mapped PTE from a swapped entry (arch) | +| __swp_entry_to_pte | Creates a swap PTE from a swp_entry_t (arch) | +---------------------------+--------------------------------------------------+ -| __pmd_to_swp_entry | Creates a swapped entry (arch) from a mapped PMD | +| __pmd_to_swp_entry | Creates a swp_entry_t (arch) from a swap PMD | +---------------------------+--------------------------------------------------+ -| __swp_to_pmd_entry | Creates a mapped PMD from a swapped entry (arch) | +| __swp_entry_to_pmd | Creates a swap PMD from a swp_entry_t (arch) | +---------------------------+--------------------------------------------------+ | is_migration_entry | Tests a migration (read or write) swapped entry | +-------------------------------+----------------------------------------------+ diff --git a/mm/debug_vm_pgtable.c b/mm/debug_vm_pgtable.c index bd8f9317b0258..d19031f275a3f 100644 --- a/mm/debug_vm_pgtable.c +++ b/mm/debug_vm_pgtable.c @@ -72,6 +72,8 @@ struct pgtable_debug_args { unsigned long fixed_pud_pfn; unsigned long fixed_pmd_pfn; unsigned long fixed_pte_pfn; + + swp_entry_t swp_entry; }; static void __init pte_basic_tests(struct pgtable_debug_args *args, int idx) @@ -698,12 +700,15 @@ static void __init pte_soft_dirty_tests(struct pgtable_debug_args *args) static void __init pte_swap_soft_dirty_tests(struct pgtable_debug_args *args) { - pte_t pte = pfn_pte(args->fixed_pte_pfn, args->page_prot); + pte_t pte; if (!IS_ENABLED(CONFIG_MEM_SOFT_DIRTY)) return; pr_debug("Validating PTE swap soft dirty\n"); + pte = swp_entry_to_pte(args->swp_entry); + WARN_ON(!is_swap_pte(pte)); + WARN_ON(!pte_swp_soft_dirty(pte_swp_mksoft_dirty(pte))); WARN_ON(pte_swp_soft_dirty(pte_swp_clear_soft_dirty(pte))); } @@ -737,7 +742,9 @@ static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args) return; pr_debug("Validating PMD swap soft dirty\n"); - pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot); + pmd = swp_entry_to_pmd(args->swp_entry); + WARN_ON(!is_swap_pmd(pmd)); + WARN_ON(!pmd_swp_soft_dirty(pmd_swp_mksoft_dirty(pmd))); WARN_ON(pmd_swp_soft_dirty(pmd_swp_clear_soft_dirty(pmd))); } @@ -748,17 +755,11 @@ static void __init pmd_swap_soft_dirty_tests(struct pgtable_debug_args *args) { static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args) { - unsigned long max_swap_offset; swp_entry_t entry, entry2; pte_t pte; pr_debug("Validating PTE swap exclusive\n"); - - /* See generic_max_swapfile_size(): probe the maximum offset */ - max_swap_offset = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0, ~0UL)))); - - /* Create a swp entry with all possible bits set */ - entry = swp_entry((1 << MAX_SWAPFILES_SHIFT) - 1, max_swap_offset); + entry = args->swp_entry; pte = swp_entry_to_pte(entry); WARN_ON(pte_swp_exclusive(pte)); @@ -782,30 +783,34 @@ static void __init pte_swap_exclusive_tests(struct pgtable_debug_args *args) static void __init pte_swap_tests(struct pgtable_debug_args *args) { - swp_entry_t swp; - pte_t pte; + swp_entry_t arch_entry; + pte_t pte1, pte2; pr_debug("Validating PTE swap\n"); - pte = pfn_pte(args->fixed_pte_pfn, args->page_prot); - swp = __pte_to_swp_entry(pte); - pte = __swp_entry_to_pte(swp); - WARN_ON(args->fixed_pte_pfn != pte_pfn(pte)); + pte1 = swp_entry_to_pte(args->swp_entry); + WARN_ON(!is_swap_pte(pte1)); + + arch_entry = __pte_to_swp_entry(pte1); + pte2 = __swp_entry_to_pte(arch_entry); + WARN_ON(memcmp(&pte1, &pte2, sizeof(pte1))); } #ifdef CONFIG_ARCH_ENABLE_THP_MIGRATION static void __init pmd_swap_tests(struct pgtable_debug_args *args) { - swp_entry_t swp; - pmd_t pmd; + swp_entry_t arch_entry; + pmd_t pmd1, pmd2; if (!has_transparent_hugepage()) return; pr_debug("Validating PMD swap\n"); - pmd = pfn_pmd(args->fixed_pmd_pfn, args->page_prot); - swp = __pmd_to_swp_entry(pmd); - pmd = __swp_entry_to_pmd(swp); - WARN_ON(args->fixed_pmd_pfn != pmd_pfn(pmd)); + pmd1 = swp_entry_to_pmd(args->swp_entry); + WARN_ON(!is_swap_pmd(pmd1)); + + arch_entry = __pmd_to_swp_entry(pmd1); + pmd2 = __swp_entry_to_pmd(arch_entry); + WARN_ON(memcmp(&pmd1, &pmd2, sizeof(pmd1))); } #else /* !CONFIG_ARCH_ENABLE_THP_MIGRATION */ static void __init pmd_swap_tests(struct pgtable_debug_args *args) { } @@ -1110,6 +1115,7 @@ static void __init init_fixed_pfns(struct pgtable_debug_args *args) static int __init init_args(struct pgtable_debug_args *args) { + unsigned long max_swap_offset; struct page *page = NULL; int ret = 0; @@ -1192,6 +1198,11 @@ static int __init init_args(struct pgtable_debug_args *args) init_fixed_pfns(args); + /* See generic_max_swapfile_size(): probe the maximum offset */ + max_swap_offset = swp_offset(pte_to_swp_entry(swp_entry_to_pte(swp_entry(0, ~0UL)))); + /* Create a swp entry with all possible bits set */ + args->swp_entry = swp_entry((1 << MAX_SWAPFILES_SHIFT) - 1, max_swap_offset); + /* * Allocate (huge) pages because some of the tests need to access * the data in the pages. The corresponding tests will be skipped