SLAB always disable irq before executing any object alloc/free operation. This is really painful in terms of performance. Benchmark result that does alloc/free repeatedly shows that each alloc/free is rougly 2 times slower than SLUB's one (27 ns : 14 ns). To improve performance, this patchset try to implement allocation fastpath without disabling irq. This is a similar way to implement allocation fastpath in SLUB. Transaction id is introduced and updated on every operation. In allocation fastpath, object in array cache is read speculartively. And then, pointer pointing object position in array cache and transaction id are updated simultaneously through this_cpu_cmpxchg_double(). If tid is unchanged until this updating, it ensures that there is no concurrent clients allocating/freeing object to this slab. So allocation could succeed without disabling irq. Above mentioned benchmark shows that alloc/free fastpath performance is improved roughly 22%. (27 ns -> 21 ns). Unfortunately, I cannot optimize free fastpath, because speculartively writing freeing object pointer into array cache cannot be possible. If anyone have a good idea to optimize free fastpath, please let me know. Thanks. Joonsoo Kim (6): mm/slab: fix gfp flags of percpu allocation at boot phase mm/slab: remove kmemleak_erase() call mm/slab: clean-up __ac_get_obj() to prepare future changes mm/slab: rearrange irq management mm/slab: cleanup ____cache_alloc() mm/slab: allocation fastpath without disabling irq include/linux/kmemleak.h | 8 -- mm/slab.c | 257 +++++++++++++++++++++++++++++++--------------- 2 files changed, 176 insertions(+), 89 deletions(-) -- 1.7.9.5 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@xxxxxxxxx. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>