[PATCH v6 10/14] arm64: mm: replace TIF_LAZY_MMU with is_lazy_mmu_mode_active()

Kevin Brodsky
2025-12-15T15:04:34Z

The generic lazy_mmu layer now tracks whether a task is in lazy MMU
mode. As a result we no longer need a TIF flag for that purpose -
let's use the new is_lazy_mmu_mode_active() helper instead.

The explicit check for in_interrupt() is no longer necessary either
as is_lazy_mmu_mode_active() always returns false in interrupt
context.

Acked-by: David Hildenbrand (Red Hat) <david@kernel.org>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
arch/arm64/include/asm/pgtable.h | 19 +++----------------
arch/arm64/include/asm/thread_info.h | 3 +--
2 files changed, 4 insertions(+), 18 deletions(-)

diff --git a/arch/arm64/include/asm/pgtable.h b/arch/arm64/include/asm/pgtable.h
index 7f528c36d53c..445e18e92221 100644
--- a/arch/arm64/include/asm/pgtable.h
+++ b/arch/arm64/include/asm/pgtable.h
@@ -62,28 +62,16 @@ static inline void emit_pte_barriers(void)

static inline void queue_pte_barriers(void)
{
- unsigned long flags;
-
- if (in_interrupt()) {
- emit_pte_barriers();
- return;
- }
-
- flags = read_thread_flags();
-
- if (flags & BIT(TIF_LAZY_MMU)) {
+ if (is_lazy_mmu_mode_active()) {
/* Avoid the atomic op if already set. */
- if (!(flags & BIT(TIF_LAZY_MMU_PENDING)))
+ if (!test_thread_flag(TIF_LAZY_MMU_PENDING))
set_thread_flag(TIF_LAZY_MMU_PENDING);
} else {
emit_pte_barriers();
}
}

-static inline void arch_enter_lazy_mmu_mode(void)
-{
- set_thread_flag(TIF_LAZY_MMU);
-}
+static inline void arch_enter_lazy_mmu_mode(void) {}

static inline void arch_flush_lazy_mmu_mode(void)
{
@@ -94,7 +82,6 @@ static inline void arch_flush_lazy_mmu_mode(void)
static inline void arch_leave_lazy_mmu_mode(void)
{
arch_flush_lazy_mmu_mode();
- clear_thread_flag(TIF_LAZY_MMU);
}

#ifdef CONFIG_TRANSPARENT_HUGEPAGE
diff --git a/arch/arm64/include/asm/thread_info.h b/arch/arm64/include/asm/thread_info.h
index a803b887b0b4..e7cd017b07c8 100644
--- a/arch/arm64/include/asm/thread_info.h
+++ b/arch/arm64/include/asm/thread_info.h
@@ -84,8 +84,7 @@ void arch_setup_new_exec(void);
#define TIF_SME_VL_INHERIT 28 /* Inherit SME vl_onexec across exec */
#define TIF_KERNEL_FPSTATE 29 /* Task is in a kernel mode FPSIMD section */
#define TIF_TSC_SIGSEGV 30 /* SIGSEGV on counter-timer access */
-#define TIF_LAZY_MMU 31 /* Task in lazy mmu mode */
-#define TIF_LAZY_MMU_PENDING 32 /* Ops pending for lazy mmu mode exit */
+#define TIF_LAZY_MMU_PENDING 31 /* Ops pending for lazy mmu mode exit */

#define _TIF_SIGPENDING (1 << TIF_SIGPENDING)
#define _TIF_NEED_RESCHED (1 << TIF_NEED_RESCHED)
--
2.51.2