Merge tag 'printk-for-5.19' of git://git.kernel.org/pub/scm/linux/kernel/git/printk...

[linux-block.git] / kernel / rcu / tree_stall.h

diff --git a/kernel/rcu/tree_stall.h b/kernel/rcu/tree_stall.h
index d612707c2ed017efadf68af6891bbb021340cbec..4995c078cff98d69af3add847adf1616bff717f7 100644 (file)
--- a/kernel/rcu/tree_stall.h
+++ b/kernel/rcu/tree_stall.h
@@ -25,6 +25,34 @@ int sysctl_max_rcu_stall_to_panic __read_mostly;
 #define RCU_STALL_MIGHT_DIV            8
 #define RCU_STALL_MIGHT_MIN            (2 * HZ)
 
+int rcu_exp_jiffies_till_stall_check(void)
+{
+       int cpu_stall_timeout = READ_ONCE(rcu_exp_cpu_stall_timeout);
+       int exp_stall_delay_delta = 0;
+       int till_stall_check;
+
+       // Zero says to use rcu_cpu_stall_timeout, but in milliseconds.
+       if (!cpu_stall_timeout)
+               cpu_stall_timeout = jiffies_to_msecs(rcu_jiffies_till_stall_check());
+
+       // Limit check must be consistent with the Kconfig limits for
+       // CONFIG_RCU_EXP_CPU_STALL_TIMEOUT, so check the allowed range.
+       // The minimum clamped value is "2UL", because at least one full
+       // tick has to be guaranteed.
+       till_stall_check = clamp(msecs_to_jiffies(cpu_stall_timeout), 2UL, 21UL * HZ);
+
+       if (cpu_stall_timeout && jiffies_to_msecs(till_stall_check) != cpu_stall_timeout)
+               WRITE_ONCE(rcu_exp_cpu_stall_timeout, jiffies_to_msecs(till_stall_check));
+
+#ifdef CONFIG_PROVE_RCU
+       /* Add extra ~25% out of till_stall_check. */
+       exp_stall_delay_delta = ((till_stall_check * 25) / 100) + 1;
+#endif
+
+       return till_stall_check + exp_stall_delay_delta;
+}
+EXPORT_SYMBOL_GPL(rcu_exp_jiffies_till_stall_check);
+
 /* Limit-check stall timeouts specified at boottime and runtime. */
 int rcu_jiffies_till_stall_check(void)
 {
@@ -565,9 +593,9 @@ static void print_other_cpu_stall(unsigned long gp_seq, unsigned long gps)
 
        for_each_possible_cpu(cpu)
                totqlen += rcu_get_n_cbs_cpu(cpu);
-       pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu)\n",
+       pr_cont("\t(detected by %d, t=%ld jiffies, g=%ld, q=%lu ncpus=%d)\n",
               smp_processor_id(), (long)(jiffies - gps),
-              (long)rcu_seq_current(&rcu_state.gp_seq), totqlen);
+              (long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
        if (ndetected) {
                rcu_dump_cpu_stacks();
 
@@ -627,9 +655,9 @@ static void print_cpu_stall(unsigned long gps)
        raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags);
        for_each_possible_cpu(cpu)
                totqlen += rcu_get_n_cbs_cpu(cpu);
-       pr_cont("\t(t=%lu jiffies g=%ld q=%lu)\n",
+       pr_cont("\t(t=%lu jiffies g=%ld q=%lu ncpus=%d)\n",
                jiffies - gps,
-               (long)rcu_seq_current(&rcu_state.gp_seq), totqlen);
+               (long)rcu_seq_current(&rcu_state.gp_seq), totqlen, rcu_state.n_online_cpus);
 
        rcu_check_gp_kthread_expired_fqs_timer();
        rcu_check_gp_kthread_starvation();