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Commit e0f23060 authored by Paul E. McKenney's avatar Paul E. McKenney Committed by Paul E. McKenney
Browse files

rcu: Update comments to reflect softirqs vs. kthreads 



We now have kthreads only for flavors of RCU that support boosting,
so update the now-misleading comments accordingly.

Signed-off-by: default avatarPaul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: default avatarPaul E. McKenney <paulmck@linux.vnet.ibm.com>
parent 72fe701b

kernel/rcutree.c

+12 −11
Original line number Diff line number Diff line
@@ -198,7 +198,7 @@ DEFINE_PER_CPU(struct rcu_dynticks, rcu_dynticks) = { 
};

#endif /* #ifdef CONFIG_NO_HZ */



static int blimit = 10;		/* Maximum callbacks per softirq. */

static int blimit = 10;		/* Maximum callbacks per rcu_do_batch. */

static int qhimark = 10000;	/* If this many pending, ignore blimit. */

static int qlowmark = 100;	/* Once only this many pending, use blimit. */
@@ -1261,7 +1261,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) 


	local_irq_restore(flags);



	/* Re-raise the RCU softirq if there are callbacks remaining. */

	/* Re-invoke RCU core processing if there are callbacks remaining. */

	if (cpu_has_callbacks_ready_to_invoke(rdp))

		invoke_rcu_core();

}
@@ -1269,7 +1269,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) 
/*

 * Check to see if this CPU is in a non-context-switch quiescent state

 * (user mode or idle loop for rcu, non-softirq execution for rcu_bh).

 * Also schedule the RCU softirq handler.

 * Also schedule RCU core processing.

 *

 * This function must be called with hardirqs disabled.  It is normally

 * invoked from the scheduling-clock interrupt.  If rcu_pending returns
@@ -1448,9 +1448,9 @@ static void force_quiescent_state(struct rcu_state *rsp, int relaxed) 
#endif /* #else #ifdef CONFIG_SMP */



/*

 * This does the RCU processing work from softirq context for the

 * specified rcu_state and rcu_data structures.  This may be called

 * only from the CPU to whom the rdp belongs.

 * This does the RCU core processing work for the specified rcu_state

 * and rcu_data structures.  This may be called only from the CPU to

 * whom the rdp belongs.

 */

static void

__rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)
@@ -1487,7 +1487,7 @@ __rcu_process_callbacks(struct rcu_state *rsp, struct rcu_data *rdp) 
}



/*

 * Do softirq processing for the current CPU.

 * Do RCU core processing for the current CPU.

 */

static void rcu_process_callbacks(struct softirq_action *unused)

{
@@ -1503,10 +1503,11 @@ static void rcu_process_callbacks(struct softirq_action *unused) 
}



/*

 * Wake up the current CPU's kthread.  This replaces raise_softirq()

 * in earlier versions of RCU.  Note that because we are running on

 * the current CPU with interrupts disabled, the rcu_cpu_kthread_task

 * cannot disappear out from under us.

 * Schedule RCU callback invocation.  If the specified type of RCU

 * does not support RCU priority boosting, just do a direct call,

 * otherwise wake up the per-CPU kernel kthread.  Note that because we

 * are running on the current CPU with interrupts disabled, the

 * rcu_cpu_kthread_task cannot disappear out from under us.

 */

static void invoke_rcu_callbacks(struct rcu_state *rsp, struct rcu_data *rdp)

{

kernel/rcutree_plugin.h

+2 −1
Original line number Diff line number Diff line
@@ -1478,7 +1478,8 @@ static int rcu_cpu_kthread_should_stop(int cpu) 


/*

 * Per-CPU kernel thread that invokes RCU callbacks.  This replaces the

 * earlier RCU softirq.

 * RCU softirq used in flavors and configurations of RCU that do not

 * support RCU priority boosting.

 */

static int rcu_cpu_kthread(void *arg)

{