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rcu: Remove obsolete force-quiescent-state statistics for debugfs 

The debugfs interface displayed statistics on RCU-pending checks but
this interface has since been removed.  This commit therefore removes the
no-longer-used rcu_state structure's ->n_force_qs_lh and ->n_force_qs_ngp
fields along with their updates.  (Though the ->n_force_qs_ngp field
was actually not used at all, embarrassingly enough.)

If this information proves necessary in the future, the corresponding
event traces will be added.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-01-10 13:10:49 -08:00
parent 01c495f72a
commit d62df57370
2 changed files with 1 additions and 8 deletions
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5
kernel/rcu/tree.c
View File

@ -2844,10 +2844,8 @@ static void force_quiescent_state(struct rcu_state *rsp)
!raw_spin_trylock(&rnp->fqslock);
if (rnp_old != NULL)
raw_spin_unlock(&rnp_old->fqslock);
if (ret) {
rsp->n_force_qs_lh++;
if (ret)
return;
}
rnp_old = rnp;
}
/* rnp_old == rcu_get_root(rsp), rnp == NULL. */
@ -2856,7 +2854,6 @@ static void force_quiescent_state(struct rcu_state *rsp)
raw_spin_lock_irqsave_rcu_node(rnp_old, flags);
raw_spin_unlock(&rnp_old->fqslock);
if (READ_ONCE(rsp->gp_flags) & RCU_GP_FLAG_FQS) {
rsp->n_force_qs_lh++;
raw_spin_unlock_irqrestore_rcu_node(rnp_old, flags);
return; /* Someone beat us to it. */
}

4
kernel/rcu/tree.h
View File

@ -355,10 +355,6 @@ struct rcu_state {
/* kthreads, if configured. */
unsigned long n_force_qs; /* Number of calls to */
/* force_quiescent_state(). */
unsigned long n_force_qs_lh; /* ~Number of calls leaving */
/* due to lock unavailable. */
unsigned long n_force_qs_ngp; /* Number of calls leaving */
/* due to no GP active. */
unsigned long gp_start; /* Time at which GP started, */
/* but in jiffies. */
unsigned long gp_activity; /* Time of last GP kthread */