• Marcin Slusarz's avatar
    slub: reduce overhead of slub_debug · c4089f98
    Marcin Slusarz authored
    
    
    slub checks for poison one byte by one, which is highly inefficient
    and shows up frequently as a highest cpu-eater in perf top.
    
    Joining reads gives nice speedup:
    
    (Compiling some project with different options)
                                     make -j12    make clean
    slub_debug disabled:             1m 27s       1.2 s
    slub_debug enabled:              1m 46s       7.6 s
    slub_debug enabled + this patch: 1m 33s       3.2 s
    
    check_bytes still shows up high, but not always at the top.
    
    Signed-off-by: default avatarMarcin Slusarz <marcin.slusarz@gmail.com>
    Cc: Christoph Lameter <cl@linux-foundation.org>
    Cc: Pekka Enberg <penberg@kernel.org>
    Cc: Matt Mackall <mpm@selenic.com>
    Cc: linux-mm@kvack.org
    Signed-off-by: default avatarPekka Enberg <penberg@kernel.org>
    c4089f98