lkml.org 
[lkml]   [2022]   [Feb]   [15]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v6 67/71] nommu: Remove uses of VMA linked list
    Date
    From: "Matthew Wilcox (Oracle)" <willy@infradead.org>

    Use the maple tree or VMA iterator instead. This is faster and will
    allow us to shrink the VMA.

    Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
    Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
    Acked-by: Vlastimil Babka <vbabka@suse.cz>
    ---
    mm/nommu.c | 15 +++++++++++----
    1 file changed, 11 insertions(+), 4 deletions(-)

    diff --git a/mm/nommu.c b/mm/nommu.c
    index f500c57a59f3..13028f93dfd9 100644
    --- a/mm/nommu.c
    +++ b/mm/nommu.c
    @@ -1370,6 +1370,7 @@ static int shrink_vma(struct mm_struct *mm,
    */
    int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list_head *uf)
    {
    + MA_STATE(mas, &mm->mm_mt, start, start);
    struct vm_area_struct *vma;
    unsigned long end;
    int ret;
    @@ -1381,7 +1382,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list
    end = start + len;

    /* find the first potentially overlapping VMA */
    - vma = find_vma(mm, start);
    + vma = mas_find(&mas, end - 1);
    if (!vma) {
    static int limit;
    if (limit < 5) {
    @@ -1400,7 +1401,7 @@ int do_munmap(struct mm_struct *mm, unsigned long start, size_t len, struct list
    return -EINVAL;
    if (end == vma->vm_end)
    goto erase_whole_vma;
    - vma = vma->vm_next;
    + vma = mas_next(&mas, end - 1);
    } while (vma);
    return -EINVAL;
    } else {
    @@ -1449,6 +1450,7 @@ SYSCALL_DEFINE2(munmap, unsigned long, addr, size_t, len)
    */
    void exit_mmap(struct mm_struct *mm)
    {
    + VMA_ITERATOR(vmi, mm, 0);
    struct vm_area_struct *vma;

    if (!mm)
    @@ -1456,12 +1458,17 @@ void exit_mmap(struct mm_struct *mm)

    mm->total_vm = 0;

    - while ((vma = mm->mmap)) {
    - mm->mmap = vma->vm_next;
    + /*
    + * Lock the mm to avoid assert complaining even though this is the only
    + * user of the mm
    + */
    + mmap_write_lock(mm);
    + for_each_vma(vmi, vma) {
    delete_vma_from_mm(vma);
    delete_vma(mm, vma);
    cond_resched();
    }
    + mmap_write_unlock(mm);
    __mt_destroy(&mm->mm_mt);
    }

    --
    2.34.1
    \
     
     \ /
      Last update: 2022-02-15 16:10    [W:2.483 / U:0.692 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site