The generic lazy_mmu layer now tracks whether a task is in lazy MMU
mode. As a result we no longer need to track whether the per-CPU TLB
batch struct is active - we know it is if in_lazy_mmu_mode() returns
true.

Signed-off-by: Kevin Brodsky <kevin.brodsky@arm.com>
---
 arch/powerpc/include/asm/book3s/64/tlbflush-hash.h | 9 ---------
 arch/powerpc/mm/book3s64/hash_tlb.c                | 2 +-
 2 files changed, 1 insertion(+), 10 deletions(-)

diff --git a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
index 623a8a8b2d0e..bbc54690d374 100644
--- a/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
+++ b/arch/powerpc/include/asm/book3s/64/tlbflush-hash.h
@@ -12,7 +12,6 @@
 #define PPC64_TLB_BATCH_NR 192
 
 struct ppc64_tlb_batch {
-	int			active;
 	unsigned long		index;
 	struct mm_struct	*mm;
 	real_pte_t		pte[PPC64_TLB_BATCH_NR];
@@ -26,8 +25,6 @@ extern void __flush_tlb_pending(struct ppc64_tlb_batch *batch);
 
 static inline void arch_enter_lazy_mmu_mode(void)
 {
-	struct ppc64_tlb_batch *batch;
-
 	if (radix_enabled())
 		return;
 	/*
@@ -35,8 +32,6 @@ static inline void arch_enter_lazy_mmu_mode(void)
 	 * operating on kernel page tables.
 	 */
 	preempt_disable();
-	batch = this_cpu_ptr(&ppc64_tlb_batch);
-	batch->active = 1;
 }
 
 static inline void arch_flush_lazy_mmu_mode(void)
@@ -51,14 +46,10 @@ static inline void arch_flush_lazy_mmu_mode(void)
 
 static inline void arch_leave_lazy_mmu_mode(void)
 {
-	struct ppc64_tlb_batch *batch;
-
 	if (radix_enabled())
 		return;
-	batch = this_cpu_ptr(&ppc64_tlb_batch);
 
 	arch_flush_lazy_mmu_mode();
-	batch->active = 0;
 	preempt_enable();
 }
 
diff --git a/arch/powerpc/mm/book3s64/hash_tlb.c b/arch/powerpc/mm/book3s64/hash_tlb.c
index 787f7a0e27f0..72b83f582b6d 100644
--- a/arch/powerpc/mm/book3s64/hash_tlb.c
+++ b/arch/powerpc/mm/book3s64/hash_tlb.c
@@ -100,7 +100,7 @@ void hpte_need_flush(struct mm_struct *mm, unsigned long addr,
 	 * Check if we have an active batch on this CPU. If not, just
 	 * flush now and return.
 	 */
-	if (!batch->active) {
+	if (!in_lazy_mmu_mode()) {
 		flush_hash_page(vpn, rpte, psize, ssize, mm_is_thread_local(mm));
 		put_cpu_var(ppc64_tlb_batch);
 		return;
-- 
2.47.0

On 15.10.25 10:27, Kevin Brodsky wrote:
> The generic lazy_mmu layer now tracks whether a task is in lazy MMU
> mode. As a result we no longer need to track whether the per-CPU TLB
> batch struct is active - we know it is if in_lazy_mmu_mode() returns
> true.

It's worth adding that disabling preemption while enabled makes sure 
that we cannot reschedule while in lazy MMU mode, so when the per-CPU 
TLB batch structure is active.


-- 
Cheers

David / dhildenb

On 23/10/2025 22:02, David Hildenbrand wrote:
> On 15.10.25 10:27, Kevin Brodsky wrote:
>> The generic lazy_mmu layer now tracks whether a task is in lazy MMU
>> mode. As a result we no longer need to track whether the per-CPU TLB
>> batch struct is active - we know it is if in_lazy_mmu_mode() returns
>> true.
>
> It's worth adding that disabling preemption while enabled makes sure
> that we cannot reschedule while in lazy MMU mode, so when the per-CPU
> TLB batch structure is active.

Yes good point, otherwise this change doesn't make sense. I'll add that.

- Kevin