rcu: remove useless ->boosted_this_gp field

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>

1 files changed, 4 insertions, 31 deletions

diff --git a/kernel/rcutiny_plugin.h b/kernel/rcutiny_plugin.h
index 0bc9f732d1a5..2b8d5293c5f4 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