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rcu: Consolidate expedited CPU selection 

Now that sync_sched_exp_select_cpus() and sync_rcu_exp_select_cpus()
are identical aside from the the argument to smp_call_function_single(),
this commit consolidates them with a functional argument.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2015-08-15 19:00:31 -07:00
parent 66fe6cbee4
commit dcdb8807ba
2 changed files with 5 additions and 63 deletions
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7
kernel/rcu/tree.c
View File

@ -3654,7 +3654,8 @@ static void synchronize_sched_expedited_cpu_stop(void *data)
* Select the nodes that the upcoming expedited grace period needs
* to wait for.
*/
static void sync_sched_exp_select_cpus(struct rcu_state *rsp)
static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
smp_call_func_t func)
{
int cpu;
unsigned long flags;
@ -3696,7 +3697,7 @@ static void sync_sched_exp_select_cpus(struct rcu_state *rsp)
for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
if (!(mask_ofl_ipi & mask))
continue;
ret = smp_call_function_single(cpu, synchronize_sched_expedited_cpu_stop, NULL, 0);
ret = smp_call_function_single(cpu, func, rsp, 0);
if (!ret)
mask_ofl_ipi &= ~mask;
}
@ -3788,7 +3789,7 @@ void synchronize_sched_expedited(void)
return; /* Someone else did our work for us. */
rcu_exp_gp_seq_start(rsp);
sync_sched_exp_select_cpus(rsp);
sync_rcu_exp_select_cpus(rsp, synchronize_sched_expedited_cpu_stop);
synchronize_sched_expedited_wait(rsp);
rcu_exp_gp_seq_end(rsp);

61
kernel/rcu/tree_plugin.h
View File

@ -708,65 +708,6 @@ static void sync_rcu_exp_handler(void *info)
rcu_report_exp_rdp(rsp, rdp, true);
}
/*
* Select the nodes that the upcoming expedited grace period needs
* to wait for.
*/
static void sync_rcu_exp_select_cpus(struct rcu_state *rsp)
{
int cpu;
unsigned long flags;
unsigned long mask;
unsigned long mask_ofl_test;
unsigned long mask_ofl_ipi;
int ret;
struct rcu_node *rnp;
sync_exp_reset_tree(rsp);
rcu_for_each_leaf_node(rsp, rnp) {
raw_spin_lock_irqsave(&rnp->lock, flags);
smp_mb__after_unlock_lock();
/* Each pass checks a CPU for identity, offline, and idle. */
mask_ofl_test = 0;
for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) {
struct rcu_data *rdp = per_cpu_ptr(rsp->rda, cpu);
struct rcu_dynticks *rdtp = &per_cpu(rcu_dynticks, cpu);
if (raw_smp_processor_id() == cpu ||
cpu_is_offline(cpu) ||
!(atomic_add_return(0, &rdtp->dynticks) & 0x1))
mask_ofl_test |= rdp->grpmask;
}
mask_ofl_ipi = rnp->expmask & ~mask_ofl_test;
/*
* Need to wait for any blocked tasks as well. Note that
* additional blocking tasks will also block the expedited
* GP until such time as the ->expmask bits are cleared.
*/
if (rcu_preempt_has_tasks(rnp))
rnp->exp_tasks = rnp->blkd_tasks.next;
raw_spin_unlock_irqrestore(&rnp->lock, flags);
/* IPI the remaining CPUs for expedited quiescent state. */
mask = 1;
for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) {
if (!(mask_ofl_ipi & mask))
continue;
ret = smp_call_function_single(cpu,
sync_rcu_exp_handler,
rsp, 0);
if (!ret)
mask_ofl_ipi &= ~mask;
}
/* Report quiescent states for those that went offline. */
mask_ofl_test |= mask_ofl_ipi;
if (mask_ofl_test)
rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false);
}
}
/**
* synchronize_rcu_expedited - Brute-force RCU grace period
*
@ -795,7 +736,7 @@ void synchronize_rcu_expedited(void)
rcu_exp_gp_seq_start(rsp);
/* Initialize the rcu_node tree in preparation for the wait. */
sync_rcu_exp_select_cpus(rsp);
sync_rcu_exp_select_cpus(rsp, sync_rcu_exp_handler);
/* Wait for snapshotted ->blkd_tasks lists to drain. */
rnp = rcu_get_root(rsp);