rcu: Update tree_exp.h function-header comments (de8cd0a5) · Commits · 戴 / test

kernel/rcu/tree_exp.h

+13 −12

Original line number	Diff line number	Diff line
		@@ -21,7 +21,7 @@ static void rcu_exp_gp_seq_start(void)
		}

		/*
		* Return then value that expedited-grace-period counter will have
		* Return the value that the expedited-grace-period counter will have
		* at the end of the current grace period.
		*/
		static __maybe_unused unsigned long rcu_exp_gp_seq_endval(void)
		@@ -39,7 +39,9 @@ static void rcu_exp_gp_seq_end(void)
		}

		/*
		* Take a snapshot of the expedited-grace-period counter.
		* Take a snapshot of the expedited-grace-period counter, which is the
		* earliest value that will indicate that a full grace period has
		* elapsed since the current time.
		*/
		static unsigned long rcu_exp_gp_seq_snap(void)
		{
		@@ -143,22 +145,18 @@ static void __maybe_unused sync_exp_reset_tree(void)
		* Return non-zero if there is no RCU expedited grace period in progress
		* for the specified rcu_node structure, in other words, if all CPUs and
		* tasks covered by the specified rcu_node structure have done their bit
		* for the current expedited grace period. Works only for preemptible
		* RCU -- other RCU implementation use other means.
		*
		* Caller must hold the specificed rcu_node structure's ->lock
		* for the current expedited grace period.
		*/
		static bool sync_rcu_exp_done(struct rcu_node *rnp)
		{
		raw_lockdep_assert_held_rcu_node(rnp);

		return rnp->exp_tasks == NULL &&
		READ_ONCE(rnp->expmask) == 0;
		}

		/*
		* Like sync_rcu_exp_done(), but this function assumes the caller doesn't
		* hold the rcu_node's ->lock, and will acquire and release the lock itself
		* Like sync_rcu_exp_done(), but where the caller does not hold the
		* rcu_node's ->lock.
		*/
		static bool sync_rcu_exp_done_unlocked(struct rcu_node *rnp)
		{
		@@ -180,8 +178,6 @@ static bool sync_rcu_exp_done_unlocked(struct rcu_node *rnp)
		* which the task was queued or to one of that rcu_node structure's ancestors,
		* recursively up the tree. (Calm down, calm down, we do the recursion
		* iteratively!)
		*
		* Caller must hold the specified rcu_node structure's ->lock.
		*/
		static void __rcu_report_exp_rnp(struct rcu_node *rnp,
		bool wake, unsigned long flags)
		@@ -189,6 +185,7 @@ static void __rcu_report_exp_rnp(struct rcu_node *rnp,
		{
		unsigned long mask;

		raw_lockdep_assert_held_rcu_node(rnp);
		for (;;) {
		if (!sync_rcu_exp_done(rnp)) {
		if (!rnp->expmask)
		@@ -452,6 +449,10 @@ static void sync_rcu_exp_select_cpus(void)
		flush_work(&rnp->rew.rew_work);
		}

		/*
		* Wait for the expedited grace period to elapse, issuing any needed
		* RCU CPU stall warnings along the way.
		*/
		static void synchronize_sched_expedited_wait(void)
		{
		int cpu;
		@@ -781,7 +782,7 @@ static int rcu_print_task_exp_stall(struct rcu_node *rnp)
		* implementations, it is still unfriendly to real-time workloads, so is
		* thus not recommended for any sort of common-case code. In fact, if
		* you are using synchronize_rcu_expedited() in a loop, please restructure
		* your code to batch your updates, and then Use a single synchronize_rcu()
		* your code to batch your updates, and then use a single synchronize_rcu()
		* instead.
		*
		* This has the same semantics as (but is more brutal than) synchronize_rcu().

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