lkml.org 
[lkml]   [2013]   [Oct]   [17]   [last100]   RSS Feed
Views: [wrap][no wrap]   [headers]  [forward] 
 
Messages in this thread
    Patch in this message
    /
    From
    Subject[PATCH 2/3] mm/mlock: prepare params outside critical region
    Date
    All mlock related syscalls prepare lock limits, lengths and
    start parameters with the mmap_sem held. Move this logic
    outside of the critical region. For the case of mlock, continue
    incrementing the amount already locked by mm->locked_vm with
    the rwsem taken.

    Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
    Cc: Michel Lespinasse <walken@google.com>
    Cc: Vlastimil Babka <vbabka@suse.cz>
    ---
    mm/mlock.c | 18 +++++++++++-------
    1 file changed, 11 insertions(+), 7 deletions(-)

    diff --git a/mm/mlock.c b/mm/mlock.c
    index d480cd6..aa7de13 100644
    --- a/mm/mlock.c
    +++ b/mm/mlock.c
    @@ -689,19 +689,21 @@ SYSCALL_DEFINE2(mlock, unsigned long, start, size_t, len)

    lru_add_drain_all(); /* flush pagevec */

    - down_write(&current->mm->mmap_sem);
    len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
    start &= PAGE_MASK;

    - locked = len >> PAGE_SHIFT;
    - locked += current->mm->locked_vm;
    -
    lock_limit = rlimit(RLIMIT_MEMLOCK);
    lock_limit >>= PAGE_SHIFT;
    + locked = len >> PAGE_SHIFT;
    +
    + down_write(&current->mm->mmap_sem);
    +
    + locked += current->mm->locked_vm;

    /* check against resource limits */
    if ((locked <= lock_limit) || capable(CAP_IPC_LOCK))
    error = do_mlock(start, len, 1);
    +
    up_write(&current->mm->mmap_sem);
    if (!error)
    error = __mm_populate(start, len, 0);
    @@ -712,11 +714,13 @@ SYSCALL_DEFINE2(munlock, unsigned long, start, size_t, len)
    {
    int ret;

    - down_write(&current->mm->mmap_sem);
    len = PAGE_ALIGN(len + (start & ~PAGE_MASK));
    start &= PAGE_MASK;
    +
    + down_write(&current->mm->mmap_sem);
    ret = do_mlock(start, len, 0);
    up_write(&current->mm->mmap_sem);
    +
    return ret;
    }

    @@ -761,12 +765,12 @@ SYSCALL_DEFINE1(mlockall, int, flags)
    if (flags & MCL_CURRENT)
    lru_add_drain_all(); /* flush pagevec */

    - down_write(&current->mm->mmap_sem);
    -
    lock_limit = rlimit(RLIMIT_MEMLOCK);
    lock_limit >>= PAGE_SHIFT;

    ret = -ENOMEM;
    + down_write(&current->mm->mmap_sem);
    +
    if (!(flags & MCL_CURRENT) || (current->mm->total_vm <= lock_limit) ||
    capable(CAP_IPC_LOCK))
    ret = do_mlockall(flags);
    --
    1.8.1.4


    \
     
     \ /
      Last update: 2013-10-18 03:21    [W:4.265 / U:0.452 seconds]
    ©2003-2020 Jasper Spaans|hosted at Digital Ocean and TransIP|Read the blog|Advertise on this site