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| author | Liam R. Howlett <Liam.Howlett@oracle.com> | 2023-05-31 21:54:02 -0400 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-06-19 16:19:28 -0700 |
| commit | 65ac132027a884c411b8f9f96d240ba2dde34dec (patch) | |
| tree | f92d17b52dd61c61ca0678003c3715426f436fd1 /include | |
| parent | 1e3be4856f49d55c60b6cd500297b06acfe216a9 (diff) | |
| download | lwn-65ac132027a884c411b8f9f96d240ba2dde34dec.tar.gz lwn-65ac132027a884c411b8f9f96d240ba2dde34dec.zip | |
userfaultfd: fix regression in userfaultfd_unmap_prep()
Android reported a performance regression in the userfaultfd unmap path.
A closer inspection on the userfaultfd_unmap_prep() change showed that a
second tree walk would be necessary in the reworked code.
Fix the regression by passing each VMA that will be unmapped through to
the userfaultfd_unmap_prep() function as they are added to the unmap list,
instead of re-walking the tree for the VMA.
Link: https://lkml.kernel.org/r/20230601015402.2819343-1-Liam.Howlett@oracle.com
Fixes: 69dbe6daf104 ("userfaultfd: use maple tree iterator to iterate VMAs")
Signed-off-by: Liam R. Howlett <Liam.Howlett@oracle.com>
Reported-by: Suren Baghdasaryan <surenb@google.com>
Suggested-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'include')
| -rw-r--r-- | include/linux/userfaultfd_k.h | 6 |
1 files changed, 3 insertions, 3 deletions
diff --git a/include/linux/userfaultfd_k.h b/include/linux/userfaultfd_k.h index d78b01524349..ac7b0c96d351 100644 --- a/include/linux/userfaultfd_k.h +++ b/include/linux/userfaultfd_k.h @@ -188,8 +188,8 @@ extern bool userfaultfd_remove(struct vm_area_struct *vma, unsigned long start, unsigned long end); -extern int userfaultfd_unmap_prep(struct mm_struct *mm, unsigned long start, - unsigned long end, struct list_head *uf); +extern int userfaultfd_unmap_prep(struct vm_area_struct *vma, + unsigned long start, unsigned long end, struct list_head *uf); extern void userfaultfd_unmap_complete(struct mm_struct *mm, struct list_head *uf); extern bool userfaultfd_wp_unpopulated(struct vm_area_struct *vma); @@ -271,7 +271,7 @@ static inline bool userfaultfd_remove(struct vm_area_struct *vma, return true; } -static inline int userfaultfd_unmap_prep(struct mm_struct *mm, +static inline int userfaultfd_unmap_prep(struct vm_area_struct *vma, unsigned long start, unsigned long end, struct list_head *uf) { |