Commit a9e056de authored Jun 09, 2025 by Ryan Roberts Committed by Andrew Morton Jul 24, 2025

mm: remove arch_flush_tlb_batched_pending() arch helper

Since commit 4b634918 ("arm64/mm: Close theoretical race where stale
TLB entry remains valid"), all arches that use tlbbatch for reclaim
(arm64, riscv, x86) implement arch_flush_tlb_batched_pending() with a
flush_tlb_mm().

So let's simplify by removing the unnecessary abstraction and doing the
flush_tlb_mm() directly in flush_tlb_batched_pending().  This effectively
reverts commit db6c1f6f ("mm/tlbbatch: introduce
arch_flush_tlb_batched_pending()").

Link: https://lkml.kernel.org/r/20250609103132.447370-1-ryan.roberts@arm.com


Signed-off-by: Ryan Roberts <ryan.roberts@arm.com>
Suggested-by: Will Deacon <will@kernel.org>
Reviewed-by: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Acked-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Anshuman Khandual <anshuman.khandual@arm.com>
Acked-by: Will Deacon <will@kernel.org>
Cc: Albert Ou <aou@eecs.berkeley.edu>
Cc: Alexandre Ghiti <alex@ghiti.fr>
Cc: Borislav Betkov <bp@alien8.de>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "H. Peter Anvin" <hpa@zytor.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Liam Howlett <liam.howlett@oracle.com>
Cc: Lorenzo Stoakes <lorenzo.stoakes@oracle.com>
Cc: Palmer Dabbelt <palmer@dabbelt.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Rik van Riel <riel@surriel.com>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Thomas Gleinxer <tglx@linutronix.de>
Cc: Vlastimil Babka <vbabka@suse.cz>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

parent 441413d2

arch/arm64/include/asm/tlbflush.h

+0 −11

Original line number	Diff line number	Diff line
		@@ -322,17 +322,6 @@ static inline bool arch_tlbbatch_should_defer(struct mm_struct *mm)
		return true;
		}

		/*
		* If mprotect/munmap/etc occurs during TLB batched flushing, we need to ensure
		* all the previously issued TLBIs targeting mm have completed. But since we
		* can be executing on a remote CPU, a DSB cannot guarantee this like it can
		* for arch_tlbbatch_flush(). Our only option is to flush the entire mm.
		*/
		static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm)
		{
		flush_tlb_mm(mm);
		}

		/*
		* To support TLB batched flush for multiple pages unmapping, we only send
		* the TLBI for each page in arch_tlbbatch_add_pending() and wait for the

arch/riscv/include/asm/tlbflush.h

+0 −1

Original line number	Diff line number	Diff line
		@@ -63,7 +63,6 @@ void flush_pud_tlb_range(struct vm_area_struct *vma, unsigned long start,
		bool arch_tlbbatch_should_defer(struct mm_struct *mm);
		void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
		struct mm_struct *mm, unsigned long start, unsigned long end);
		void arch_flush_tlb_batched_pending(struct mm_struct *mm);
		void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);

		extern unsigned long tlb_flush_all_threshold;

arch/riscv/mm/tlbflush.c

+0 −5

Original line number	Diff line number	Diff line
		@@ -234,11 +234,6 @@ void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *batch,
		mmu_notifier_arch_invalidate_secondary_tlbs(mm, start, end);
		}

		void arch_flush_tlb_batched_pending(struct mm_struct *mm)
		{
		flush_tlb_mm(mm);
		}

		void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch)
		{
		__flush_tlb_range(NULL, &batch->cpumask,

arch/x86/include/asm/tlbflush.h

+0 −5

Original line number	Diff line number	Diff line
		@@ -356,11 +356,6 @@ static inline void arch_tlbbatch_add_pending(struct arch_tlbflush_unmap_batch *b
		mmu_notifier_arch_invalidate_secondary_tlbs(mm, 0, -1UL);
		}

		static inline void arch_flush_tlb_batched_pending(struct mm_struct *mm)
		{
		flush_tlb_mm(mm);
		}

		extern void arch_tlbbatch_flush(struct arch_tlbflush_unmap_batch *batch);

		static inline bool pte_flags_need_flush(unsigned long oldflags,

mm/rmap.c

+1 −1

Original line number	Diff line number	Diff line
		@@ -746,7 +746,7 @@ void flush_tlb_batched_pending(struct mm_struct *mm)
		int flushed = batch >> TLB_FLUSH_BATCH_FLUSHED_SHIFT;

		if (pending != flushed) {
		arch_flush_tlb_batched_pending(mm);
		flush_tlb_mm(mm);
		/*
		* If the new TLB flushing is pending during flushing, leave
		* mm->tlb_flush_batched as is, to avoid losing flushing.