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Date: Tue, 26 Mar 2019 16:22:21 -0700
From: "Paul E. McKenney" <paulmck@...ux.ibm.com>
To: rcu@...r.kernel.org
Cc: linux-kernel@...r.kernel.org, mingo@...nel.org,
jiangshanlai@...il.com, dipankar@...ibm.com,
akpm@...ux-foundation.org, mathieu.desnoyers@...icios.com,
josh@...htriplett.org, tglx@...utronix.de, peterz@...radead.org,
rostedt@...dmis.org, dhowells@...hat.com, edumazet@...gle.com,
fweisbec@...il.com, oleg@...hat.com, joel@...lfernandes.org,
"Paul E. McKenney" <paulmck@...ux.ibm.com>
Subject: [PATCH tip/core/rcu 07/11] rcu: Move FAST_NO_HZ stall-warning code to tree_stall.h
This commit further consolidates the stall-warning code by moving
print_cpu_stall_info() and its helper functions along with
zero_cpu_stall_ticks() to kernel/rcu/tree_stall.h.
Signed-off-by: Paul E. McKenney <paulmck@...ux.ibm.com>
---
kernel/rcu/tree.h | 1 -
kernel/rcu/tree_plugin.h | 80 ----------------------------------------
kernel/rcu/tree_stall.h | 80 ++++++++++++++++++++++++++++++++++++++++
3 files changed, 80 insertions(+), 81 deletions(-)
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index d73472af49e7..49bf3b00bb50 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -416,7 +416,6 @@ static void rcu_prepare_for_idle(void);
static bool rcu_preempt_has_tasks(struct rcu_node *rnp);
static bool rcu_preempt_need_deferred_qs(struct task_struct *t);
static void rcu_preempt_deferred_qs(struct task_struct *t);
-static void print_cpu_stall_info(int cpu);
static void zero_cpu_stall_ticks(struct rcu_data *rdp);
static bool rcu_nocb_cpu_needs_barrier(int cpu);
static struct swait_queue_head *rcu_nocb_gp_get(struct rcu_node *rnp);
diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h
index 2df5bb04fd7a..a1f9d7c15bd8 100644
--- a/kernel/rcu/tree_plugin.h
+++ b/kernel/rcu/tree_plugin.h
@@ -1528,86 +1528,6 @@ static void rcu_cleanup_after_idle(void)
#endif /* #else #if !defined(CONFIG_RCU_FAST_NO_HZ) */
-#ifdef CONFIG_RCU_FAST_NO_HZ
-
-static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
-{
- struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
-
- sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c",
- rdp->last_accelerate & 0xffff, jiffies & 0xffff,
- ".l"[rdp->all_lazy],
- ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)],
- ".D"[!rdp->tick_nohz_enabled_snap]);
-}
-
-#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */
-
-static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
-{
- *cp = '\0';
-}
-
-#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */
-
-/*
- * Print out diagnostic information for the specified stalled CPU.
- *
- * If the specified CPU is aware of the current RCU grace period, then
- * print the number of scheduling clock interrupts the CPU has taken
- * during the time that it has been aware. Otherwise, print the number
- * of RCU grace periods that this CPU is ignorant of, for example, "1"
- * if the CPU was aware of the previous grace period.
- *
- * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info.
- */
-static void print_cpu_stall_info(int cpu)
-{
- unsigned long delta;
- char fast_no_hz[72];
- struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
- char *ticks_title;
- unsigned long ticks_value;
-
- /*
- * We could be printing a lot while holding a spinlock. Avoid
- * triggering hard lockup.
- */
- touch_nmi_watchdog();
-
- ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq);
- if (ticks_value) {
- ticks_title = "GPs behind";
- } else {
- ticks_title = "ticks this GP";
- ticks_value = rdp->ticks_this_gp;
- }
- print_cpu_stall_fast_no_hz(fast_no_hz, cpu);
- delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
- pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n",
- cpu,
- "O."[!!cpu_online(cpu)],
- "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
- "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
- !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' :
- rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' :
- "!."[!delta],
- ticks_value, ticks_title,
- rcu_dynticks_snap(rdp) & 0xfff,
- rdp->dynticks_nesting, rdp->dynticks_nmi_nesting,
- rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
- READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
- fast_no_hz);
-}
-
-/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */
-static void zero_cpu_stall_ticks(struct rcu_data *rdp)
-{
- rdp->ticks_this_gp = 0;
- rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id());
- WRITE_ONCE(rdp->last_fqs_resched, jiffies);
-}
-
#ifdef CONFIG_RCU_NOCB_CPU
/*
diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index 7ef3b596e45f..19b915380a6f 100644
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -223,6 +223,86 @@ static void panic_on_rcu_stall(void)
panic("RCU Stall\n");
}
+#ifdef CONFIG_RCU_FAST_NO_HZ
+
+static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
+{
+ struct rcu_data *rdp = &per_cpu(rcu_data, cpu);
+
+ sprintf(cp, "last_accelerate: %04lx/%04lx, Nonlazy posted: %c%c%c",
+ rdp->last_accelerate & 0xffff, jiffies & 0xffff,
+ ".l"[rdp->all_lazy],
+ ".L"[!rcu_segcblist_n_nonlazy_cbs(&rdp->cblist)],
+ ".D"[!rdp->tick_nohz_enabled_snap]);
+}
+
+#else /* #ifdef CONFIG_RCU_FAST_NO_HZ */
+
+static void print_cpu_stall_fast_no_hz(char *cp, int cpu)
+{
+ *cp = '\0';
+}
+
+#endif /* #else #ifdef CONFIG_RCU_FAST_NO_HZ */
+
+/*
+ * Print out diagnostic information for the specified stalled CPU.
+ *
+ * If the specified CPU is aware of the current RCU grace period, then
+ * print the number of scheduling clock interrupts the CPU has taken
+ * during the time that it has been aware. Otherwise, print the number
+ * of RCU grace periods that this CPU is ignorant of, for example, "1"
+ * if the CPU was aware of the previous grace period.
+ *
+ * Also print out idle and (if CONFIG_RCU_FAST_NO_HZ) idle-entry info.
+ */
+static void print_cpu_stall_info(int cpu)
+{
+ unsigned long delta;
+ char fast_no_hz[72];
+ struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
+ char *ticks_title;
+ unsigned long ticks_value;
+
+ /*
+ * We could be printing a lot while holding a spinlock. Avoid
+ * triggering hard lockup.
+ */
+ touch_nmi_watchdog();
+
+ ticks_value = rcu_seq_ctr(rcu_state.gp_seq - rdp->gp_seq);
+ if (ticks_value) {
+ ticks_title = "GPs behind";
+ } else {
+ ticks_title = "ticks this GP";
+ ticks_value = rdp->ticks_this_gp;
+ }
+ print_cpu_stall_fast_no_hz(fast_no_hz, cpu);
+ delta = rcu_seq_ctr(rdp->mynode->gp_seq - rdp->rcu_iw_gp_seq);
+ pr_err("\t%d-%c%c%c%c: (%lu %s) idle=%03x/%ld/%#lx softirq=%u/%u fqs=%ld %s\n",
+ cpu,
+ "O."[!!cpu_online(cpu)],
+ "o."[!!(rdp->grpmask & rdp->mynode->qsmaskinit)],
+ "N."[!!(rdp->grpmask & rdp->mynode->qsmaskinitnext)],
+ !IS_ENABLED(CONFIG_IRQ_WORK) ? '?' :
+ rdp->rcu_iw_pending ? (int)min(delta, 9UL) + '0' :
+ "!."[!delta],
+ ticks_value, ticks_title,
+ rcu_dynticks_snap(rdp) & 0xfff,
+ rdp->dynticks_nesting, rdp->dynticks_nmi_nesting,
+ rdp->softirq_snap, kstat_softirqs_cpu(RCU_SOFTIRQ, cpu),
+ READ_ONCE(rcu_state.n_force_qs) - rcu_state.n_force_qs_gpstart,
+ fast_no_hz);
+}
+
+/* Zero ->ticks_this_gp and snapshot the number of RCU softirq handlers. */
+static void zero_cpu_stall_ticks(struct rcu_data *rdp)
+{
+ rdp->ticks_this_gp = 0;
+ rdp->softirq_snap = kstat_softirqs_cpu(RCU_SOFTIRQ, smp_processor_id());
+ WRITE_ONCE(rdp->last_fqs_resched, jiffies);
+}
+
static void print_other_cpu_stall(unsigned long gp_seq)
{
int cpu;
--
2.17.1
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