• Joe Korty's avatar
    slab: NUMA slab allocator migration bugfix · 6d2144d3
    Joe Korty authored
    NUMA slab allocator cpu migration bugfix
    
    The NUMA slab allocator (specifically, cache_alloc_refill)
    is not refreshing its local copies of what cpu and what
    numa node it is on, when it drops and reacquires the irq
    block that it inherited from its caller.  As a result
    those values become invalid if an attempt to migrate the
    process to another numa node occured while the irq block
    had been dropped.
    
    The solution is to make cache_alloc_refill reload these
    variables whenever it drops and reacquires the irq block.
    
    The error is very difficult to hit.  When it does occur,
    one gets the following oops + stack traceback bits in
    check_spinlock_acquired:
    
    	kernel BUG at mm/slab.c:2417
    	cache_alloc_refill+0xe6
    	kmem_cache_alloc+0xd0
    	...
    
    This patch was developed against 2.6.23, ported to and
    compiled-tested only against 2.6.25-rc4.
    Signed-off-by: default avatarJoe Korty <joe.korty@ccur.com>
    Signed-off-by: default avatarChristoph Lameter <clameter@sgi.com>
    6d2144d3
slab.c 115 KB