Commit 499d7e7e authored by Frederic Weisbecker's avatar Frederic Weisbecker Committed by Boqun Feng
Browse files

rcu: Rename jiffies_till_flush to jiffies_lazy_flush 



The variable name jiffies_till_flush is too generic and therefore:

* It may shadow a global variable
* It doesn't tell on what it operates

Make the name more precise, along with the related APIs.

Reviewed-by: default avatarJoel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: default avatarFrederic Weisbecker <frederic@kernel.org>
Reviewed-by: default avatarPaul E. McKenney <paulmck@kernel.org>
Signed-off-by: default avatarBoqun Feng <boqun.feng@gmail.com>
parent 41bccc98

kernel/rcu/rcu.h

+4 −4
Original line number Diff line number Diff line
@@ -543,11 +543,11 @@ enum rcutorture_type { 
};



#if defined(CONFIG_RCU_LAZY)

unsigned long rcu_lazy_get_jiffies_till_flush(void);

void rcu_lazy_set_jiffies_till_flush(unsigned long j);

unsigned long rcu_get_jiffies_lazy_flush(void);

void rcu_set_jiffies_lazy_flush(unsigned long j);

#else

static inline unsigned long rcu_lazy_get_jiffies_till_flush(void) { return 0; }

static inline void rcu_lazy_set_jiffies_till_flush(unsigned long j) { }

static inline unsigned long rcu_get_jiffies_lazy_flush(void) { return 0; }

static inline void rcu_set_jiffies_lazy_flush(unsigned long j) { }

#endif



#if defined(CONFIG_TREE_RCU)

kernel/rcu/rcuscale.c

+3 −3
Original line number Diff line number Diff line
@@ -764,9 +764,9 @@ kfree_scale_init(void) 


	if (kfree_by_call_rcu) {

		/* do a test to check the timeout. */

		orig_jif = rcu_lazy_get_jiffies_till_flush();

		orig_jif = rcu_get_jiffies_lazy_flush();



		rcu_lazy_set_jiffies_till_flush(2 * HZ);

		rcu_set_jiffies_lazy_flush(2 * HZ);

		rcu_barrier();



		jif_start = jiffies;
@@ -775,7 +775,7 @@ kfree_scale_init(void) 


		smp_cond_load_relaxed(&rcu_lazy_test1_cb_called, VAL == 1);



		rcu_lazy_set_jiffies_till_flush(orig_jif);

		rcu_set_jiffies_lazy_flush(orig_jif);



		if (WARN_ON_ONCE(jiffies_at_lazy_cb - jif_start < 2 * HZ)) {

			pr_alert("ERROR: call_rcu() CBs are not being lazy as expected!\n");

kernel/rcu/tree_nocb.h

+11 −11
Original line number Diff line number Diff line
@@ -256,6 +256,7 @@ static bool wake_nocb_gp(struct rcu_data *rdp, bool force) 
	return __wake_nocb_gp(rdp_gp, rdp, force, flags);

}



#ifdef CONFIG_RCU_LAZY

/*

 * LAZY_FLUSH_JIFFIES decides the maximum amount of time that

 * can elapse before lazy callbacks are flushed. Lazy callbacks
@@ -264,21 +265,20 @@ static bool wake_nocb_gp(struct rcu_data *rdp, bool force) 
 * left unsubmitted to RCU after those many jiffies.

 */

#define LAZY_FLUSH_JIFFIES (10 * HZ)

static unsigned long jiffies_till_flush = LAZY_FLUSH_JIFFIES;

static unsigned long jiffies_lazy_flush = LAZY_FLUSH_JIFFIES;



#ifdef CONFIG_RCU_LAZY

// To be called only from test code.

void rcu_lazy_set_jiffies_till_flush(unsigned long jif)

void rcu_set_jiffies_lazy_flush(unsigned long jif)

{

	jiffies_till_flush = jif;

	jiffies_lazy_flush = jif;

}

EXPORT_SYMBOL(rcu_lazy_set_jiffies_till_flush);

EXPORT_SYMBOL(rcu_set_jiffies_lazy_flush);



unsigned long rcu_lazy_get_jiffies_till_flush(void)

unsigned long rcu_get_jiffies_lazy_flush(void)

{

	return jiffies_till_flush;

	return jiffies_lazy_flush;

}

EXPORT_SYMBOL(rcu_lazy_get_jiffies_till_flush);

EXPORT_SYMBOL(rcu_get_jiffies_lazy_flush);

#endif



/*
@@ -299,7 +299,7 @@ static void wake_nocb_gp_defer(struct rcu_data *rdp, int waketype, 
	 */

	if (waketype == RCU_NOCB_WAKE_LAZY &&

	    rdp->nocb_defer_wakeup == RCU_NOCB_WAKE_NOT) {

		mod_timer(&rdp_gp->nocb_timer, jiffies + jiffies_till_flush);

		mod_timer(&rdp_gp->nocb_timer, jiffies + rcu_get_jiffies_lazy_flush());

		WRITE_ONCE(rdp_gp->nocb_defer_wakeup, waketype);

	} else if (waketype == RCU_NOCB_WAKE_BYPASS) {

		mod_timer(&rdp_gp->nocb_timer, jiffies + 2);
@@ -482,7 +482,7 @@ static bool rcu_nocb_try_bypass(struct rcu_data *rdp, struct rcu_head *rhp, 
	// flush ->nocb_bypass to ->cblist.

	if ((ncbs && !bypass_is_lazy && j != READ_ONCE(rdp->nocb_bypass_first)) ||

	    (ncbs &&  bypass_is_lazy &&

	     (time_after(j, READ_ONCE(rdp->nocb_bypass_first) + jiffies_till_flush))) ||

	     (time_after(j, READ_ONCE(rdp->nocb_bypass_first) + rcu_get_jiffies_lazy_flush()))) ||

	    ncbs >= qhimark) {

		rcu_nocb_lock(rdp);

		*was_alldone = !rcu_segcblist_pend_cbs(&rdp->cblist);
@@ -723,7 +723,7 @@ static void nocb_gp_wait(struct rcu_data *my_rdp) 
		lazy_ncbs = READ_ONCE(rdp->lazy_len);



		if (bypass_ncbs && (lazy_ncbs == bypass_ncbs) &&

		    (time_after(j, READ_ONCE(rdp->nocb_bypass_first) + jiffies_till_flush) ||

		    (time_after(j, READ_ONCE(rdp->nocb_bypass_first) + rcu_get_jiffies_lazy_flush()) ||

		     bypass_ncbs > 2 * qhimark)) {

			flush_bypass = true;

		} else if (bypass_ncbs && (lazy_ncbs != bypass_ncbs) &&