[PATCH 6/9] mm/memory: split non-tlb flushing part from zap_page_range_single()

SeongJae Park
2025-03-10T17:23:30Z

Some of zap_page_range_single() callers such as [process_]madvise() with
MADV_DONEED[_LOCKED] cannot batch tlb flushes because
zap_page_range_single() does tlb flushing for each invocation. Split
out the body of zap_page_range_single() except mmu_gather object
initialization and gathered tlb entries flushing parts for such batched
tlb flushing usage.

Signed-off-by: SeongJae Park <sj@kernel.org>
---
mm/memory.c | 36 ++++++++++++++++++++++--------------
1 file changed, 22 insertions(+), 14 deletions(-)

diff --git a/mm/memory.c b/mm/memory.c
index 78c7ee62795e..88c478e2ed1a 100644
--- a/mm/memory.c
+++ b/mm/memory.c
@@ -1995,38 +1995,46 @@ void unmap_vmas(struct mmu_gather *tlb, struct ma_state *mas,
mmu_notifier_invalidate_range_end(&range);
}

-/**
- * zap_page_range_single - remove user pages in a given range
- * @vma: vm_area_struct holding the applicable pages
- * @address: starting address of pages to zap
- * @size: number of bytes to zap
- * @details: details of shared cache invalidation
- *
- * The range must fit into one VMA.
- */
-void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
+static void unmap_vma_single(struct mmu_gather *tlb,
+ struct vm_area_struct *vma, unsigned long address,
unsigned long size, struct zap_details *details)
{
const unsigned long end = address + size;
struct mmu_notifier_range range;
- struct mmu_gather tlb;

mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma->vm_mm,
address, end);
hugetlb_zap_begin(vma, &range.start, &range.end);
- tlb_gather_mmu(&tlb, vma->vm_mm);
update_hiwater_rss(vma->vm_mm);
mmu_notifier_invalidate_range_start(&range);
/*
* unmap 'address-end' not 'range.start-range.end' as range
* could have been expanded for hugetlb pmd sharing.
*/
- unmap_single_vma(&tlb, vma, address, end, details, false);
+ unmap_single_vma(tlb, vma, address, end, details, false);
mmu_notifier_invalidate_range_end(&range);
- tlb_finish_mmu(&tlb);
hugetlb_zap_end(vma, details);
}

+/**
+ * zap_page_range_single - remove user pages in a given range
+ * @vma: vm_area_struct holding the applicable pages
+ * @address: starting address of pages to zap
+ * @size: number of bytes to zap
+ * @details: details of shared cache invalidation
+ *
+ * The range must fit into one VMA.
+ */
+void zap_page_range_single(struct vm_area_struct *vma, unsigned long address,
+ unsigned long size, struct zap_details *details)
+{
+ struct mmu_gather tlb;
+
+ tlb_gather_mmu(&tlb, vma->vm_mm);
+ unmap_vma_single(&tlb, vma, address, size, details);
+ tlb_finish_mmu(&tlb);
+}
+
/**
* zap_vma_ptes - remove ptes mapping the vma
* @vma: vm_area_struct holding ptes to be zapped
--
2.39.5