• Christoph Lameter's avatar
    slab allocators: Remove SLAB_DEBUG_INITIAL flag · 50953fe9
    Christoph Lameter authored
    
    
    I have never seen a use of SLAB_DEBUG_INITIAL.  It is only supported by
    SLAB.
    
    I think its purpose was to have a callback after an object has been freed
    to verify that the state is the constructor state again?  The callback is
    performed before each freeing of an object.
    
    I would think that it is much easier to check the object state manually
    before the free.  That also places the check near the code object
    manipulation of the object.
    
    Also the SLAB_DEBUG_INITIAL callback is only performed if the kernel was
    compiled with SLAB debugging on.  If there would be code in a constructor
    handling SLAB_DEBUG_INITIAL then it would have to be conditional on
    SLAB_DEBUG otherwise it would just be dead code.  But there is no such code
    in the kernel.  I think SLUB_DEBUG_INITIAL is too problematic to make real
    use of, difficult to understand and there are easier ways to accomplish the
    same effect (i.e.  add debug code before kfree).
    
    There is a related flag SLAB_CTOR_VERIFY that is frequently checked to be
    clear in fs inode caches.  Remove the pointless checks (they would even be
    pointless without removeal of SLAB_DEBUG_INITIAL) from the fs constructors.
    
    This is the last slab flag that SLUB did not support.  Remove the check for
    unimplemented flags from SLUB.
    Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
    Signed-off-by: default avatarAndrew Morton <akpm@linux-foundation.org>
    Signed-off-by: default avatarLinus Torvalds <torvalds@linux-foundation.org>
    50953fe9
super.c 102 KB