rcu/nohz: Turn off tick for offloaded CPUs (0bd55c69) · Commits · 戴 / test

kernel/rcu/tree_plugin.h

+9 −7

Original line number	Diff line number	Diff line
		@@ -1226,10 +1226,10 @@ static void rcu_prepare_kthreads(int cpu)
		#if !defined(CONFIG_RCU_FAST_NO_HZ)

		/*
		* Check to see if any future RCU-related work will need to be done
		* by the current CPU, even if none need be done immediately, returning
		* 1 if so. This function is part of the RCU implementation; it is -not-
		* an exported member of the RCU API.
		* Check to see if any future non-offloaded RCU-related work will need
		* to be done by the current CPU, even if none need be done immediately,
		* returning 1 if so. This function is part of the RCU implementation;
		* it is -not- an exported member of the RCU API.
		*
		* Because we not have RCU_FAST_NO_HZ, just check whether or not this
		* CPU has RCU callbacks queued.
		@@ -1237,7 +1237,8 @@ static void rcu_prepare_kthreads(int cpu)
		int rcu_needs_cpu(u64 basemono, u64 *nextevt)
		{
		*nextevt = KTIME_MAX;
		return !rcu_segcblist_empty(&this_cpu_ptr(&rcu_data)->cblist);
		return !rcu_segcblist_empty(&this_cpu_ptr(&rcu_data)->cblist) &&
		!rcu_segcblist_is_offloaded(&this_cpu_ptr(&rcu_data)->cblist);
		}

		/*
		@@ -1338,8 +1339,9 @@ int rcu_needs_cpu(u64 basemono, u64 *nextevt)

		lockdep_assert_irqs_disabled();

		/* If no callbacks, RCU doesn't need the CPU. */
		if (rcu_segcblist_empty(&rdp->cblist)) {
		/* If no non-offloaded callbacks, RCU doesn't need the CPU. */
		if (rcu_segcblist_empty(&rdp->cblist) \|\|
		rcu_segcblist_is_offloaded(&this_cpu_ptr(&rcu_data)->cblist)) {
		*nextevt = KTIME_MAX;
		return 0;
		}