lkml.org 
[lkml]   [2021]   [Jan]   [12]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH v2 11/70] kernel/fork: Convert dup_mmap to use maple tree
    Date
    Use the maple tree iterator to duplicate the mm_struct trees.

    Signed-off-by: Liam R. Howlett <Liam.Howlett@Oracle.com>
    ---
    include/linux/sched/mm.h | 3 +++
    kernel/fork.c | 22 +++++++++++++++++-----
    2 files changed, 20 insertions(+), 5 deletions(-)

    diff --git a/include/linux/sched/mm.h b/include/linux/sched/mm.h
    index d5ece7a9a403f..919e2e44b764e 100644
    --- a/include/linux/sched/mm.h
    +++ b/include/linux/sched/mm.h
    @@ -8,6 +8,7 @@
    #include <linux/mm_types.h>
    #include <linux/gfp.h>
    #include <linux/sync_core.h>
    +#include <linux/maple_tree.h>

    /*
    * Routines for handling mm_structs
    @@ -67,11 +68,13 @@ static inline void mmdrop(struct mm_struct *mm)
    */
    static inline void mmget(struct mm_struct *mm)
    {
    + mt_set_in_rcu(&mm->mm_mt);
    atomic_inc(&mm->mm_users);
    }

    static inline bool mmget_not_zero(struct mm_struct *mm)
    {
    + mt_set_in_rcu(&mm->mm_mt);
    return atomic_inc_not_zero(&mm->mm_users);
    }

    diff --git a/kernel/fork.c b/kernel/fork.c
    index 8c7273b0d4b77..8fcbd970666c3 100644
    --- a/kernel/fork.c
    +++ b/kernel/fork.c
    @@ -472,7 +472,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
    struct vm_area_struct *mpnt, *tmp, *prev, **pprev;
    struct rb_node **rb_link, *rb_parent;
    int retval;
    - unsigned long charge;
    + unsigned long charge = 0;
    + MA_STATE(old_mas, &oldmm->mm_mt, 0, 0);
    + MA_STATE(mas, &mm->mm_mt, 0, 0);
    LIST_HEAD(uf);

    uprobe_start_dup_mmap();
    @@ -506,7 +508,12 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
    goto out;

    prev = NULL;
    - for (mpnt = oldmm->mmap; mpnt; mpnt = mpnt->vm_next) {
    +
    + retval = mas_entry_count(&mas, oldmm->map_count);
    + if (retval)
    + goto fail_nomem;
    +
    + mas_for_each(&old_mas, mpnt, ULONG_MAX) {
    struct file *file;

    if (mpnt->vm_flags & VM_DONTCOPY) {
    @@ -520,7 +527,7 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
    */
    if (fatal_signal_pending(current)) {
    retval = -EINTR;
    - goto out;
    + goto loop_out;
    }
    if (mpnt->vm_flags & VM_ACCOUNT) {
    unsigned long len = vma_pages(mpnt);
    @@ -589,7 +596,9 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
    rb_parent = &tmp->vm_rb;

    /* Link the vma into the MT */
    - vma_store(mm, tmp);
    + mas.index = tmp->vm_start;
    + mas.last = tmp->vm_end - 1;
    + mas_store(&mas, tmp);

    mm->map_count++;
    if (!(tmp->vm_flags & VM_WIPEONFORK))
    @@ -599,14 +608,16 @@ static __latent_entropy int dup_mmap(struct mm_struct *mm,
    tmp->vm_ops->open(tmp);

    if (retval)
    - goto out;
    + goto loop_out;
    }
    /* a new mm has just been created */
    retval = arch_dup_mmap(oldmm, mm);
    +loop_out:
    out:
    mmap_write_unlock(mm);
    flush_tlb_mm(oldmm);
    mmap_write_unlock(oldmm);
    + mas_destroy(&mas);
    dup_userfaultfd_complete(&uf);
    fail_uprobe_end:
    uprobe_end_dup_mmap();
    @@ -1076,6 +1087,7 @@ static inline void __mmput(struct mm_struct *mm)
    {
    VM_BUG_ON(atomic_read(&mm->mm_users));

    + mt_clear_in_rcu(&mm->mm_mt);
    uprobe_clear_state(mm);
    exit_aio(mm);
    ksm_exit(mm);
    --
    2.28.0
    \
     
     \ /
      Last update: 2021-01-12 17:15    [W:4.970 / U:0.008 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site