[PATCH 3/3] cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags

When we change cpuset.memory_spread_{page,slab}, cpuset will flip PF_SPREAD_{PAGE,SLAB} bit of tsk->flags for each task in that cpuset. This should be done using atomic bitops, but currently we don't, which is broken. Tetsuo reported a hard-to-reproduce kernel crash on RHEL6, which happend when

[PATCH 3/3] cpuset: PF_SPREAD_PAGE and PF_SPREAD_SLAB should be atomic flags

When we change cpuset.memory_spread_{page,slab}, cpuset will flip PF_SPREAD_{PAGE,SLAB} bit of tsk-flags for each task in that cpuset. This should be done using atomic bitops, but currently we don't, which is broken. Tetsuo reported a hard-to-reproduce kernel crash on RHEL6, which happend when