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rcu: Remove rsp parameter from rcu_gp_kthread() and friends 

There now is only one rcu_state structure in a given build of the
Linux kernel, so there is no need to pass it as a parameter to RCU's
functions.  This commit therefore removes the rsp parameter from
rcu_gp_init(), rcu_gp_fqs_check_wake(), rcu_gp_fqs(), rcu_gp_cleanup(),
and rcu_gp_kthread().

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-03 17:22:34 -07:00
parent 22212332c1
commit 0854a05c9f
1 changed files with 15 additions and 12 deletions
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27
kernel/rcu/tree.c
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@ -1832,13 +1832,14 @@ static void rcu_gp_slow(int delay)
/* /*
* Initialize a new grace period. Return false if no grace period required. * Initialize a new grace period. Return false if no grace period required.
*/ */
static bool rcu_gp_init(struct rcu_state *rsp) static bool rcu_gp_init(void)
{ {
unsigned long flags; unsigned long flags;
unsigned long oldmask; unsigned long oldmask;
unsigned long mask; unsigned long mask;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp = rcu_get_root(); struct rcu_node *rnp = rcu_get_root();
struct rcu_state *rsp = &rcu_state;
WRITE_ONCE(rsp->gp_activity, jiffies); WRITE_ONCE(rsp->gp_activity, jiffies);
raw_spin_lock_irq_rcu_node(rnp); raw_spin_lock_irq_rcu_node(rnp);
@ -1963,12 +1964,12 @@ static bool rcu_gp_init(struct rcu_state *rsp)
* Helper function for swait_event_idle_exclusive() wakeup at force-quiescent-state * Helper function for swait_event_idle_exclusive() wakeup at force-quiescent-state
* time. * time.
*/ */
static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp) static bool rcu_gp_fqs_check_wake(int *gfp)
{ {
struct rcu_node *rnp = rcu_get_root(); struct rcu_node *rnp = rcu_get_root();
/* Someone like call_rcu() requested a force-quiescent-state scan. */ /* Someone like call_rcu() requested a force-quiescent-state scan. */
*gfp = READ_ONCE(rsp->gp_flags); *gfp = READ_ONCE(rcu_state.gp_flags);
if (*gfp & RCU_GP_FLAG_FQS) if (*gfp & RCU_GP_FLAG_FQS)
return true; return true;
@ -1982,9 +1983,10 @@ static bool rcu_gp_fqs_check_wake(struct rcu_state *rsp, int *gfp)
/* /*
* Do one round of quiescent-state forcing. * Do one round of quiescent-state forcing.
*/ */
static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time) static void rcu_gp_fqs(bool first_time)
{ {
struct rcu_node *rnp = rcu_get_root(); struct rcu_node *rnp = rcu_get_root();
struct rcu_state *rsp = &rcu_state;
WRITE_ONCE(rsp->gp_activity, jiffies); WRITE_ONCE(rsp->gp_activity, jiffies);
rsp->n_force_qs++; rsp->n_force_qs++;
@ -2007,13 +2009,14 @@ static void rcu_gp_fqs(struct rcu_state *rsp, bool first_time)
/* /*
* Clean up after the old grace period. * Clean up after the old grace period.
*/ */
static void rcu_gp_cleanup(struct rcu_state *rsp) static void rcu_gp_cleanup(void)
{ {
unsigned long gp_duration; unsigned long gp_duration;
bool needgp = false; bool needgp = false;
unsigned long new_gp_seq; unsigned long new_gp_seq;
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_node *rnp = rcu_get_root(); struct rcu_node *rnp = rcu_get_root();
struct rcu_state *rsp = &rcu_state;
struct swait_queue_head *sq; struct swait_queue_head *sq;
WRITE_ONCE(rsp->gp_activity, jiffies); WRITE_ONCE(rsp->gp_activity, jiffies);
@ -2090,13 +2093,13 @@ static void rcu_gp_cleanup(struct rcu_state *rsp)
/* /*
* Body of kthread that handles grace periods. * Body of kthread that handles grace periods.
*/ */
static int __noreturn rcu_gp_kthread(void *arg) static int __noreturn rcu_gp_kthread(void *unused)
{ {
bool first_gp_fqs; bool first_gp_fqs;
int gf; int gf;
unsigned long j; unsigned long j;
int ret; int ret;
struct rcu_state *rsp = arg; struct rcu_state *rsp = &rcu_state;
struct rcu_node *rnp = rcu_get_root(); struct rcu_node *rnp = rcu_get_root();
rcu_bind_gp_kthread(); rcu_bind_gp_kthread();
@ -2112,7 +2115,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
RCU_GP_FLAG_INIT); RCU_GP_FLAG_INIT);
rsp->gp_state = RCU_GP_DONE_GPS; rsp->gp_state = RCU_GP_DONE_GPS;
/* Locking provides needed memory barrier. */ /* Locking provides needed memory barrier. */
if (rcu_gp_init(rsp)) if (rcu_gp_init())
break; break;
cond_resched_tasks_rcu_qs(); cond_resched_tasks_rcu_qs();
WRITE_ONCE(rsp->gp_activity, jiffies); WRITE_ONCE(rsp->gp_activity, jiffies);
@ -2137,7 +2140,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
TPS("fqswait")); TPS("fqswait"));
rsp->gp_state = RCU_GP_WAIT_FQS; rsp->gp_state = RCU_GP_WAIT_FQS;
ret = swait_event_idle_timeout_exclusive(rsp->gp_wq, ret = swait_event_idle_timeout_exclusive(rsp->gp_wq,
rcu_gp_fqs_check_wake(rsp, &gf), j); rcu_gp_fqs_check_wake(&gf), j);
rsp->gp_state = RCU_GP_DOING_FQS; rsp->gp_state = RCU_GP_DOING_FQS;
/* Locking provides needed memory barriers. */ /* Locking provides needed memory barriers. */
/* If grace period done, leave loop. */ /* If grace period done, leave loop. */
@ -2150,7 +2153,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
trace_rcu_grace_period(rsp->name, trace_rcu_grace_period(rsp->name,
READ_ONCE(rsp->gp_seq), READ_ONCE(rsp->gp_seq),
TPS("fqsstart")); TPS("fqsstart"));
rcu_gp_fqs(rsp, first_gp_fqs); rcu_gp_fqs(first_gp_fqs);
first_gp_fqs = false; first_gp_fqs = false;
trace_rcu_grace_period(rsp->name, trace_rcu_grace_period(rsp->name,
READ_ONCE(rsp->gp_seq), READ_ONCE(rsp->gp_seq),
@ -2178,7 +2181,7 @@ static int __noreturn rcu_gp_kthread(void *arg)
/* Handle grace-period end. */ /* Handle grace-period end. */
rsp->gp_state = RCU_GP_CLEANUP; rsp->gp_state = RCU_GP_CLEANUP;
rcu_gp_cleanup(rsp); rcu_gp_cleanup();
rsp->gp_state = RCU_GP_CLEANED; rsp->gp_state = RCU_GP_CLEANED;
} }
} }
@ -3744,7 +3747,7 @@ static int __init rcu_spawn_gp_kthread(void)
rcu_scheduler_fully_active = 1; rcu_scheduler_fully_active = 1;
for_each_rcu_flavor(rsp) { for_each_rcu_flavor(rsp) {
t = kthread_create(rcu_gp_kthread, rsp, "%s", rsp->name); t = kthread_create(rcu_gp_kthread, NULL, "%s", rsp->name);
BUG_ON(IS_ERR(t)); BUG_ON(IS_ERR(t));
rnp = rcu_get_root(); rnp = rcu_get_root();
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);