diff options
| -rw-r--r-- | mm/madvise.c | 27 |
1 files changed, 16 insertions, 11 deletions
diff --git a/mm/madvise.c b/mm/madvise.c index 944b5e52d81..75b81ad1f98 100644 --- a/mm/madvise.c +++ b/mm/madvise.c @@ -19,6 +19,21 @@ static long madvise_behavior(struct vm_area_struct * vma, unsigned long start, { struct mm_struct * mm = vma->vm_mm; int error = 0; + int new_flags = vma->vm_flags & ~VM_READHINTMASK; + + switch (behavior) { + case MADV_SEQUENTIAL: + new_flags |= VM_SEQ_READ; + break; + case MADV_RANDOM: + new_flags |= VM_RAND_READ; + break; + default: + break; + } + + if (new_flags == vma->vm_flags) + goto out; if (start != vma->vm_start) { error = split_vma(mm, vma, start, 1); @@ -36,17 +51,7 @@ static long madvise_behavior(struct vm_area_struct * vma, unsigned long start, * vm_flags is protected by the mmap_sem held in write mode. */ VM_ClearReadHint(vma); - - switch (behavior) { - case MADV_SEQUENTIAL: - vma->vm_flags |= VM_SEQ_READ; - break; - case MADV_RANDOM: - vma->vm_flags |= VM_RAND_READ; - break; - default: - break; - } + vma->vm_flags = new_flags; out: if (error == -ENOMEM) |