diff options
| author | Matthew Wilcox (Oracle) <willy@infradead.org> | 2023-07-24 20:54:03 +0200 |
|---|---|---|
| committer | Andrew Morton <akpm@linux-foundation.org> | 2023-08-18 19:12:51 +0200 |
| commit | 4ec31152a80d83d74d231d964703a721236244ef (patch) | |
| tree | c038eef92d6b55069f2a1bd34c8129fae68278e4 /mm/memory.c | |
| parent | mm: allow per-VMA locks on file-backed VMAs (diff) | |
| download | linux-4ec31152a80d83d74d231d964703a721236244ef.tar.xz linux-4ec31152a80d83d74d231d964703a721236244ef.zip | |
mm: move FAULT_FLAG_VMA_LOCK check from handle_mm_fault()
Handle a little more of the page fault path outside the mmap sem. The
hugetlb path doesn't need to check whether the VMA is anonymous; the
VM_HUGETLB flag is only set on hugetlbfs VMAs. There should be no
performance change from the previous commit; this is simply a step to ease
bisection of any problems.
Link: https://lkml.kernel.org/r/20230724185410.1124082-4-willy@infradead.org
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Suren Baghdasaryan <surenb@google.com>
Cc: Arjun Roy <arjunroy@google.com>
Cc: Eric Dumazet <edumazet@google.com>
Cc: Punit Agrawal <punit.agrawal@bytedance.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'mm/memory.c')
| -rw-r--r-- | mm/memory.c | 18 |
1 files changed, 9 insertions, 9 deletions
diff --git a/mm/memory.c b/mm/memory.c index b2b17c66f87a..2a5f4883d9a5 100644 --- a/mm/memory.c +++ b/mm/memory.c @@ -4984,10 +4984,10 @@ unlock: } /* - * By the time we get here, we already hold the mm semaphore - * - * The mmap_lock may have been released depending on flags and our - * return value. See filemap_fault() and __folio_lock_or_retry(). + * On entry, we hold either the VMA lock or the mmap_lock + * (FAULT_FLAG_VMA_LOCK tells you which). If VM_FAULT_RETRY is set in + * the result, the mmap_lock is not held on exit. See filemap_fault() + * and __folio_lock_or_retry(). */ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, unsigned long address, unsigned int flags) @@ -5006,6 +5006,11 @@ static vm_fault_t __handle_mm_fault(struct vm_area_struct *vma, p4d_t *p4d; vm_fault_t ret; + if ((flags & FAULT_FLAG_VMA_LOCK) && !vma_is_anonymous(vma)) { + vma_end_read(vma); + return VM_FAULT_RETRY; + } + pgd = pgd_offset(mm, address); p4d = p4d_alloc(mm, pgd, address); if (!p4d) @@ -5222,11 +5227,6 @@ vm_fault_t handle_mm_fault(struct vm_area_struct *vma, unsigned long address, goto out; } - if ((flags & FAULT_FLAG_VMA_LOCK) && !vma_is_anonymous(vma)) { - vma_end_read(vma); - return VM_FAULT_RETRY; - } - /* * Enable the memcg OOM handling for faults triggered in user * space. Kernel faults are handled more gracefully. |