2036d94a7b
Because newly offlined CPUs continue executing after completing the CPU_DYING notifiers, they legitimately enter the scheduler and use RCU while appearing to be offline. This calls for a more sophisticated approach as follows: 1. RCU marks the CPU online during the CPU_UP_PREPARE phase. 2. RCU marks the CPU offline during the CPU_DEAD phase. 3. Diagnostics regarding use of read-side RCU by offline CPUs use RCU's accounting rather than the cpu_online_map. (Note that __call_rcu() still uses cpu_online_map to detect illegal invocations within CPU_DYING notifiers.) 4. Offline CPUs are prevented from hanging the system by force_quiescent_state(), which pays attention to cpu_online_map. Some additional work (in a later commit) will be needed to guarantee that force_quiescent_state() waits a full jiffy before assuming that a CPU is offline, for example, when called from idle entry. (This commit also makes the one-jiffy wait explicit, since the old-style implicit wait can now be defeated by RCU_FAST_NO_HZ and by rcutorture.) This approach avoids the false positives encountered when attempting to use more exact classification of CPU online/offline state. Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> |
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| .. | ||
| 00-INDEX | ||
| NMI-RCU.txt | ||
| RTFP.txt | ||
| UP.txt | ||
| arrayRCU.txt | ||
| checklist.txt | ||
| listRCU.txt | ||
| lockdep-splat.txt | ||
| lockdep.txt | ||
| rcu.txt | ||
| rcubarrier.txt | ||
| rculist_nulls.txt | ||
| rcuref.txt | ||
| stallwarn.txt | ||
| torture.txt | ||
| trace.txt | ||
| whatisRCU.txt | ||