From ee628d9cc8d5b96fdceeb270cf662efc4f85f2b6 Mon Sep 17 00:00:00 2001 From: Kevin Brodsky Date: Mon, 15 Dec 2025 15:03:23 +0000 Subject: [PATCH] mm: add basic tests for lazy_mmu Add basic KUnit tests for the generic aspects of the lazy MMU mode: ensure that it appears active when it should, depending on how enable/disable and pause/resume pairs are nested. [akpm@linux-foundation.org: export ppc64_tlb_batch and __flush_tlb_pending to modules] [ritesh.list@gmail.com: use EXPORT_SYMBOL_IF_KUNIT()] Link: https://lkml.kernel.org/r/87a4zhkt6h.ritesh.list@gmail.com [kevin.brodsky@arm.com: move MODULE_IMPORT_NS(), add comment] Link: https://lkml.kernel.org/r/20251217163812.2633648-2-kevin.brodsky@arm.com Link: https://lkml.kernel.org/r/20251215150323.2218608-15-kevin.brodsky@arm.com Signed-off-by: Kevin Brodsky Reviewed-by: Yeoreum Yun Signed-off-by: Ritesh Harjani (IBM) Acked-by: David Hildenbrand (Red Hat) Cc: Alexander Gordeev Cc: Andreas Larsson Cc: Anshuman Khandual Cc: Borislav Betkov Cc: Boris Ostrovsky Cc: Catalin Marinas Cc: Christophe Leroy Cc: David S. Miller Cc: David Woodhouse Cc: "H. Peter Anvin" Cc: Ingo Molnar Cc: Jann Horn Cc: Juegren Gross Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Madhavan Srinivasan Cc: Michael Ellerman Cc: Michal Hocko Cc: Mike Rapoport Cc: Nicholas Piggin Cc: Peter Zijlstra Cc: Ritesh Harjani (IBM) Cc: Ryan Roberts Cc: Suren Baghdasaryan Cc: Thomas Gleinxer Cc: Venkat Rao Bagalkote Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/powerpc/mm/book3s64/hash_tlb.c | 4 +- mm/Kconfig | 12 +++++ mm/Makefile | 1 + mm/tests/lazy_mmu_mode_kunit.c | 74 +++++++++++++++++++++++++++++ 4 files changed, 90 insertions(+), 1 deletion(-) create mode 100644 mm/tests/lazy_mmu_mode_kunit.c diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c index fbdeb8981ae7..ec2941cec815 100644 --- a/arch/powerpc/mm/book3s64/hash_tlb.c +++ b/arch/powerpc/mm/book3s64/hash_tlb.c @@ -25,11 +25,12 @@ #include #include #include - +#include #include DEFINE_PER_CPU(struct ppc64_tlb_batch, ppc64_tlb_batch); +EXPORT_SYMBOL_IF_KUNIT(ppc64_tlb_batch); /* * A linux PTE was changed and the corresponding hash table entry @@ -154,6 +155,7 @@ void __flush_tlb_pending(struct ppc64_tlb_batch *batch) flush_hash_range(i, local); batch->index = 0; } +EXPORT_SYMBOL_IF_KUNIT(__flush_tlb_pending); void hash__tlb_flush(struct mmu_gather *tlb) { diff --git a/mm/Kconfig b/mm/Kconfig index 7c2520e6a6b3..5f4d6e5b5715 100644 --- a/mm/Kconfig +++ b/mm/Kconfig @@ -1475,6 +1475,18 @@ config ARCH_HAS_LAZY_MMU_MODE MMU-related architectural state to be deferred until the mode is exited. See for details. +config LAZY_MMU_MODE_KUNIT_TEST + tristate "KUnit tests for the lazy MMU mode" if !KUNIT_ALL_TESTS + depends on ARCH_HAS_LAZY_MMU_MODE + depends on KUNIT + default KUNIT_ALL_TESTS + help + Enable this option to check that the lazy MMU mode interface behaves + as expected. Only tests for the generic interface are included (not + architecture-specific behaviours). + + If unsure, say N. + source "mm/damon/Kconfig" endmenu diff --git a/mm/Makefile b/mm/Makefile index 2d0570a16e5b..9175f8cc6565 100644 --- a/mm/Makefile +++ b/mm/Makefile @@ -147,3 +147,4 @@ obj-$(CONFIG_SHRINKER_DEBUG) += shrinker_debug.o obj-$(CONFIG_EXECMEM) += execmem.o obj-$(CONFIG_TMPFS_QUOTA) += shmem_quota.o obj-$(CONFIG_PT_RECLAIM) += pt_reclaim.o +obj-$(CONFIG_LAZY_MMU_MODE_KUNIT_TEST) += tests/lazy_mmu_mode_kunit.o diff --git a/mm/tests/lazy_mmu_mode_kunit.c b/mm/tests/lazy_mmu_mode_kunit.c new file mode 100644 index 000000000000..1c23456b467e --- /dev/null +++ b/mm/tests/lazy_mmu_mode_kunit.c @@ -0,0 +1,74 @@ +// SPDX-License-Identifier: GPL-2.0-only +#include +#include + +/* For some symbols referenced by arch_{enter,leave}_lazy_mmu_mode on powerpc */ +MODULE_IMPORT_NS("EXPORTED_FOR_KUNIT_TESTING"); + +static void expect_not_active(struct kunit *test) +{ + KUNIT_EXPECT_FALSE(test, is_lazy_mmu_mode_active()); +} + +static void expect_active(struct kunit *test) +{ + KUNIT_EXPECT_TRUE(test, is_lazy_mmu_mode_active()); +} + +static void lazy_mmu_mode_active(struct kunit *test) +{ + expect_not_active(test); + + lazy_mmu_mode_enable(); + expect_active(test); + + { + /* Nested section */ + lazy_mmu_mode_enable(); + expect_active(test); + + lazy_mmu_mode_disable(); + expect_active(test); + } + + { + /* Paused section */ + lazy_mmu_mode_pause(); + expect_not_active(test); + + { + /* No effect (paused) */ + lazy_mmu_mode_enable(); + expect_not_active(test); + + lazy_mmu_mode_disable(); + expect_not_active(test); + + lazy_mmu_mode_pause(); + expect_not_active(test); + + lazy_mmu_mode_resume(); + expect_not_active(test); + } + + lazy_mmu_mode_resume(); + expect_active(test); + } + + lazy_mmu_mode_disable(); + expect_not_active(test); +} + +static struct kunit_case lazy_mmu_mode_test_cases[] = { + KUNIT_CASE(lazy_mmu_mode_active), + {} +}; + +static struct kunit_suite lazy_mmu_mode_test_suite = { + .name = "lazy_mmu_mode", + .test_cases = lazy_mmu_mode_test_cases, +}; +kunit_test_suite(lazy_mmu_mode_test_suite); + +MODULE_DESCRIPTION("Tests for the lazy MMU mode"); +MODULE_LICENSE("GPL"); -- 2.47.3