| 摘要 |
Read-copy update (RCU) grace period initialization and CPU hotplugging are synchronized without a sleeplock. Periodic RCU grace period initialization includes, for each node of a combining tree, copying a first bitmask indicating online/offline status of a set of CPUs to a second bitmask indicating RCU quiescent state status of the CPUs. Periodic CPU hotplug operations include indicating CPU online/offline status to leaf nodes associated with the CPUs. This status is indicated without manipulating any bits in the first bitmask of the leaf nodes. Prior to each RCU grace period initialization, RCU grace period pre-initialization is performed at each leaf node. The RCU grace period pre-initialization includes (1) updating the first bitmask to account for the CPU hotplug operations, and (2) if this results in the first bitmask transitioning between fully cleared and not-fully cleared states, the state change is conditionally propagated to a higher level node. |
