+ hugetlb-remove-duplicate-mmu-notifications.patch added to mm-hotfixes-unstable branch - Linux-stable-mirror

11 Nov 2022

The patch titled
     Subject: hugetlb: remove duplicate mmu notifications
has been added to the -mm mm-hotfixes-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...
This patch will later appear in the mm-hotfixes-unstable branch at
    git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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*** Remember to use Documentation/process/submit-checklist.rst when testing your code ***
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branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Mike Kravetz mike.kravetz@oracle.com
Subject: hugetlb: remove duplicate mmu notifications
Date: Fri, 11 Nov 2022 15:26:27 -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/20221111232628.290160-3-mike.kravetz@oracle.com
Fixes: 90e7e7f5ef3f ("mm: enable MADV_DONTNEED for hugetlb mappings")
Signed-off-by: Mike Kravetz mike.kravetz@oracle.com
Reported-by: Wei Chen harperchen1110@gmail.com
Cc: stable@vger.kernel.org
Cc: Axel Rasmussen axelrasmussen@google.com
Cc: David Hildenbrand david@redhat.com
Cc: Matthew Wilcox willy@infradead.org
Cc: Mina Almasry almasrymina@google.com
Cc: Nadav Amit nadav.amit@gmail.com
Cc: Naoya Horiguchi naoya.horiguchi@linux.dev
Cc: Peter Xu peterx@redhat.com
Cc: Rik van Riel riel@surriel.com
Cc: Vlastimil Babka vbabka@suse.cz
Signed-off-by: Andrew Morton akpm@linux-foundation.org
---
mm/hugetlb.c |   18 +++++++++---------
 1 file changed, 9 insertions(+), 9 deletions(-)

--- a/mm/hugetlb.c~hugetlb-remove-duplicate-mmu-notifications
+++ a/mm/hugetlb.c
@@ -5064,7 +5064,6 @@ 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;
@@ -5079,13 +5078,6 @@ 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) {
@@ -5174,7 +5166,6 @@ static void __unmap_hugepage_range(struc
    	if (ref_page)
    		break;
    }
-	mmu_notifier_invalidate_range_end(&range);
    tlb_end_vma(tlb, vma);
/*
@@ -5202,6 +5193,7 @@ 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);
/*
@@ -5221,10 +5213,18 @@ 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@oracle.com are
ipc-shm-call-underlying-open-close-vm_ops.patch
madvise-use-zap_page_range_single-for-madvise-dontneed.patch
hugetlb-remove-duplicate-mmu-notifications.patch
hugetlb-dont-delete-vma_lock-in-hugetlb-madv_dontneed-processing.patch
selftests-vm-update-hugetlb-madvise.patch

    