The patch titled
Subject: hugetlb: remove duplicate mmu notifications
has been added to the -mm mm-unstable branch. Its filename is
hugetlb-remove-duplicate-mmu-notifications.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/hugetlb-remove-duplicate-mmu-notifications.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Subject: hugetlb: remove duplicate mmu notifications
Date: Mon, 14 Nov 2022 15:55:07 -0800
The common hugetlb unmap routine __unmap_hugepage_range performs mmu
notification calls. However, in the case where __unmap_hugepage_range is
called via __unmap_hugepage_range_final, mmu notification calls are
performed earlier in other calling routines.
Remove mmu notification calls from __unmap_hugepage_range. Add
notification calls to the only other caller: unmap_hugepage_range.
unmap_hugepage_range is called for truncation and hole punch, so change
notification type from UNMAP to CLEAR as this is more appropriate.
Link: https://lkml.kernel.org/r/20221114235507.294320-4-mike.kravetz@xxxxxxxxxx
Signed-off-by: Mike Kravetz <mike.kravetz@xxxxxxxxxx>
Suggested-by: Peter Xu <peterx@xxxxxxxxxx>
Cc: Wei Chen <harperchen1110@xxxxxxxxx>
Cc: Axel Rasmussen <axelrasmussen@xxxxxxxxxx>
Cc: David Hildenbrand <david@xxxxxxxxxx>
Cc: Matthew Wilcox <willy@xxxxxxxxxxxxx>
Cc: Mina Almasry <almasrymina@xxxxxxxxxx>
Cc: Nadav Amit <nadav.amit@xxxxxxxxx>
Cc: Naoya Horiguchi <naoya.horiguchi@xxxxxxxxx>
Cc: Rik van Riel <riel@xxxxxxxxxxx>
Cc: Vlastimil Babka <vbabka@xxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/hugetlb.c | 18 +++++++++---------
1 file changed, 9 insertions(+), 9 deletions(-)
--- a/mm/hugetlb.c~hugetlb-remove-duplicate-mmu-notifications
+++ a/mm/hugetlb.c
@@ -5074,7 +5074,6 @@ static void __unmap_hugepage_range(struc
struct page *page;
struct hstate *h = hstate_vma(vma);
unsigned long sz = huge_page_size(h);
- struct mmu_notifier_range range;
unsigned long last_addr_mask;
bool force_flush = false;
@@ -5089,13 +5088,6 @@ static void __unmap_hugepage_range(struc
tlb_change_page_size(tlb, sz);
tlb_start_vma(tlb, vma);
- /*
- * If sharing possible, alert mmu notifiers of worst case.
- */
- mmu_notifier_range_init(&range, MMU_NOTIFY_UNMAP, 0, vma, mm, start,
- end);
- adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
- mmu_notifier_invalidate_range_start(&range);
last_addr_mask = hugetlb_mask_last_page(h);
address = start;
for (; address < end; address += sz) {
@@ -5180,7 +5172,6 @@ static void __unmap_hugepage_range(struc
if (ref_page)
break;
}
- mmu_notifier_invalidate_range_end(&range);
tlb_end_vma(tlb, vma);
/*
@@ -5208,6 +5199,7 @@ void __unmap_hugepage_range_final(struct
hugetlb_vma_lock_write(vma);
i_mmap_lock_write(vma->vm_file->f_mapping);
+ /* mmu notification performed in caller */
__unmap_hugepage_range(tlb, vma, start, end, ref_page, zap_flags);
if (zap_flags & ZAP_FLAG_UNMAP) { /* final unmap */
@@ -5232,10 +5224,18 @@ void unmap_hugepage_range(struct vm_area
unsigned long end, struct page *ref_page,
zap_flags_t zap_flags)
{
+ struct mmu_notifier_range range;
struct mmu_gather tlb;
+ mmu_notifier_range_init(&range, MMU_NOTIFY_CLEAR, 0, vma, vma->vm_mm,
+ start, end);
+ adjust_range_if_pmd_sharing_possible(vma, &range.start, &range.end);
+ mmu_notifier_invalidate_range_start(&range);
tlb_gather_mmu(&tlb, vma->vm_mm);
+
__unmap_hugepage_range(&tlb, vma, start, end, ref_page, zap_flags);
+
+ mmu_notifier_invalidate_range_end(&range);
tlb_finish_mmu(&tlb);
}
_
Patches currently in -mm which might be from mike.kravetz@xxxxxxxxxx are
ipc-shm-call-underlying-open-close-vm_ops.patch
madvise-use-zap_page_range_single-for-madvise-dontneed.patch
hugetlb-dont-delete-vma_lock-in-hugetlb-madv_dontneed-processing.patch
selftests-vm-update-hugetlb-madvise.patch
hugetlb-remove-duplicate-mmu-notifications.patch
