The patch titled
Subject: hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb
has been added to the -mm tree. Its filename is
hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb.patch
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------------------------------------------------------
From: "Aneesh Kumar K.V" <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Subject: hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb
i_mmap_mutex lock was added in unmap_single_vma by 502717f4e ("hugetlb:
fix linked list corruption in unmap_hugepage_range()") but we don't use
page->lru in unmap_hugepage_range any more. Also the lock was taken
higher up in the stack in some code path. That would result in deadlock.
unmap_mapping_range (i_mmap_mutex)
-> unmap_mapping_range_tree
-> unmap_mapping_range_vma
-> zap_page_range_single
-> unmap_single_vma
-> unmap_hugepage_range (i_mmap_mutex)
For shared pagetable support for huge pages, since pagetable pages are ref
counted we don't need any lock during huge_pmd_unshare. We do take
i_mmap_mutex in huge_pmd_share while walking the vma_prio_tree in mapping.
(39dde65c9940c97f ("shared page table for hugetlb page")).
Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@xxxxxxxxxxxxxxxxxx>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
Cc: Hillf Danton <dhillf@xxxxxxxxx>
Cc: Michal Hocko <mhocko@xxxxxxx>
Cc: Andrea Arcangeli <aarcange@xxxxxxxxxx>
Cc: Johannes Weiner <hannes@xxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
mm/memory.c | 5 +----
1 file changed, 1 insertion(+), 4 deletions(-)
diff -puN mm/memory.c~hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb mm/memory.c
--- a/mm/memory.c~hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb
+++ a/mm/memory.c
@@ -1329,11 +1329,8 @@ static void unmap_single_vma(struct mmu_
* Since no pte has actually been setup, it is
* safe to do nothing in this case.
*/
- if (vma->vm_file) {
- mutex_lock(&vma->vm_file->f_mapping->i_mmap_mutex);
+ if (vma->vm_file)
__unmap_hugepage_range(tlb, vma, start, end, NULL);
- mutex_unlock(&vma->vm_file->f_mapping->i_mmap_mutex);
- }
} else
unmap_page_range(tlb, vma, start, end, details);
}
_
Subject: Subject: hugetlb: avoid taking i_mmap_mutex in unmap_single_vma() for hugetlb
Patches currently in -mm which might be from aneesh.kumar@xxxxxxxxxxxxxxxxxx are
linux-next.patch
hugetlbfs-lockdep-annotate-root-inode-properly.patch
hugetlb-rename-max_hstate-to-hugetlb_max_hstate.patch
hugetlbfs-dont-use-err_ptr-with-vm_fault-values.patch
hugetlbfs-add-an-inline-helper-for-finding-hstate-index.patch
hugetlb-use-mmu_gather-instead-of-a-temporary-linked-list-for-accumulating-pages.patch
hugetlb-avoid-taking-i_mmap_mutex-in-unmap_single_vma-for-hugetlb.patch
hugetlb-simplify-migrate_huge_page.patch
memcg-add-hugetlb-extension.patch
hugetlb-add-charge-uncharge-calls-for-hugetlb-alloc-free.patch
memcg-track-resource-index-in-cftype-private.patch
hugetlbfs-add-memcg-control-files-for-hugetlbfs.patch
hugetlbfs-add-a-list-for-tracking-in-use-hugetlb-pages.patch
memcg-move-hugetlb-resource-count-to-parent-cgroup-on-memcg-removal.patch
hugetlb-migrate-memcg-info-from-oldpage-to-new-page-during-migration.patch
memcg-add-memory-controller-documentation-for-hugetlb-management.patch
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