[PATCH tip/core/rcu 26/86] rcu: remove useless ->boosted_this_gp field

Paul E. McKenney
2011-05-01T13:31:31Z

From: Paul E. McKenney <paul.mckenney@linaro.org>

The ->boosted_this_gp field is a holdover from an earlier design that
was to carry out multiple boost operations in parallel. It is not required
by the current design, which boosts one task at a time.

Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
---
kernel/rcutiny_plugin.h | 35 ++++-------------------------------
1 files changed, 4 insertions(+), 31 deletions(-)

diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index 0bc9f73..2b8d529 100644
--- a/kernel/rcutiny_plugin.h
+++ b/kernel/rcutiny_plugin.h
@@ -100,7 +100,6 @@ struct rcu_preempt_ctrlblk {
u8 completed; /* Last grace period completed. */
/* If all three are equal, RCU is idle. */
#ifdef CONFIG_RCU_BOOST
- s8 boosted_this_gp; /* Has boosting already happened? */
unsigned long boost_time; /* When to start boosting (jiffies) */
#endif /* #ifdef CONFIG_RCU_BOOST */
#ifdef CONFIG_RCU_TRACE
@@ -112,7 +111,6 @@ struct rcu_preempt_ctrlblk {
unsigned long n_normal_balk_blkd_tasks;
unsigned long n_normal_balk_gp_tasks;
unsigned long n_normal_balk_boost_tasks;
- unsigned long n_normal_balk_boosted;
unsigned long n_normal_balk_notyet;
unsigned long n_normal_balk_nos;
unsigned long n_exp_balk_blkd_tasks;
@@ -219,36 +217,19 @@ static void show_tiny_preempt_stats(struct seq_file *m)
"N."[!rcu_preempt_ctrlblk.gp_tasks],
"E."[!rcu_preempt_ctrlblk.exp_tasks]);
#ifdef CONFIG_RCU_BOOST
- seq_printf(m, " ttb=%c btg=",
- "B."[!rcu_preempt_ctrlblk.boost_tasks]);
- switch (rcu_preempt_ctrlblk.boosted_this_gp) {
- case -1:
- seq_puts(m, "exp");
- break;
- case 0:
- seq_puts(m, "no");
- break;
- case 1:
- seq_puts(m, "begun");
- break;
- case 2:
- seq_puts(m, "done");
- break;
- default:
- seq_printf(m, "?%d?", rcu_preempt_ctrlblk.boosted_this_gp);
- }
- seq_printf(m, " ntb=%lu neb=%lu nnb=%lu j=%04x bt=%04x\n",
+ seq_printf(m, "%sttb=%c ntb=%lu neb=%lu nnb=%lu j=%04x bt=%04x\n",
+ " ",
+ "B."[!rcu_preempt_ctrlblk.boost_tasks],
rcu_preempt_ctrlblk.n_tasks_boosted,
rcu_preempt_ctrlblk.n_exp_boosts,
rcu_preempt_ctrlblk.n_normal_boosts,
(int)(jiffies & 0xffff),
(int)(rcu_preempt_ctrlblk.boost_time & 0xffff));
- seq_printf(m, " %s: nt=%lu gt=%lu bt=%lu b=%lu ny=%lu nos=%lu\n",
+ seq_printf(m, " %s: nt=%lu gt=%lu bt=%lu ny=%lu nos=%lu\n",
"normal balk",
rcu_preempt_ctrlblk.n_normal_balk_blkd_tasks,
rcu_preempt_ctrlblk.n_normal_balk_gp_tasks,
rcu_preempt_ctrlblk.n_normal_balk_boost_tasks,
- rcu_preempt_ctrlblk.n_normal_balk_boosted,
rcu_preempt_ctrlblk.n_normal_balk_notyet,
rcu_preempt_ctrlblk.n_normal_balk_nos);
seq_printf(m, " exp balk: bt=%lu nos=%lu\n",
@@ -277,7 +258,6 @@ static int rcu_boost(void)
if (rcu_preempt_ctrlblk.boost_tasks == NULL)
return 0; /* Nothing to boost. */
raw_local_irq_save(flags);
- rcu_preempt_ctrlblk.boosted_this_gp++;
t = container_of(rcu_preempt_ctrlblk.boost_tasks, struct task_struct,
rcu_node_entry);
np = rcu_next_node_entry(t);
@@ -287,7 +267,6 @@ static int rcu_boost(void)
raw_local_irq_restore(flags);
rt_mutex_lock(&mtx);
RCU_TRACE(rcu_preempt_ctrlblk.n_tasks_boosted++);
- rcu_preempt_ctrlblk.boosted_this_gp++;
rt_mutex_unlock(&mtx);
return rcu_preempt_ctrlblk.boost_tasks != NULL;
}
@@ -310,7 +289,6 @@ static int rcu_initiate_boost(void)
}
if (rcu_preempt_ctrlblk.gp_tasks != NULL &&
rcu_preempt_ctrlblk.boost_tasks == NULL &&
- rcu_preempt_ctrlblk.boosted_this_gp == 0 &&
ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time)) {
rcu_preempt_ctrlblk.boost_tasks = rcu_preempt_ctrlblk.gp_tasks;
invoke_rcu_kthread();
@@ -331,7 +309,6 @@ static void rcu_initiate_expedited_boost(void)
if (!list_empty(&rcu_preempt_ctrlblk.blkd_tasks)) {
rcu_preempt_ctrlblk.boost_tasks =
rcu_preempt_ctrlblk.blkd_tasks.next;
- rcu_preempt_ctrlblk.boosted_this_gp = -1;
invoke_rcu_kthread();
RCU_TRACE(rcu_preempt_ctrlblk.n_exp_boosts++);
} else
@@ -347,8 +324,6 @@ static void rcu_initiate_expedited_boost(void)
static void rcu_preempt_boost_start_gp(void)
{
rcu_preempt_ctrlblk.boost_time = jiffies + RCU_BOOST_DELAY_JIFFIES;
- if (rcu_preempt_ctrlblk.boosted_this_gp > 0)
- rcu_preempt_ctrlblk.boosted_this_gp = 0;
}

#else /* #ifdef CONFIG_RCU_BOOST */
@@ -934,8 +909,6 @@ static void rcu_initiate_boost_trace(void)
rcu_preempt_ctrlblk.n_normal_balk_gp_tasks++;
else if (rcu_preempt_ctrlblk.boost_tasks != NULL)
rcu_preempt_ctrlblk.n_normal_balk_boost_tasks++;
- else if (rcu_preempt_ctrlblk.boosted_this_gp != 0)
- rcu_preempt_ctrlblk.n_normal_balk_boosted++;
else if (!ULONG_CMP_GE(jiffies, rcu_preempt_ctrlblk.boost_time))
rcu_preempt_ctrlblk.n_normal_balk_notyet++;
else
--
1.7.3.2