diff options
Diffstat (limited to 'debian/patches-rt/0028-rcu-Mark-emergency-sections-in-rcu-stalls.patch')
| -rw-r--r-- | debian/patches-rt/0028-rcu-Mark-emergency-sections-in-rcu-stalls.patch | 128 |
1 files changed, 128 insertions, 0 deletions
diff --git a/debian/patches-rt/0028-rcu-Mark-emergency-sections-in-rcu-stalls.patch b/debian/patches-rt/0028-rcu-Mark-emergency-sections-in-rcu-stalls.patch new file mode 100644 index 0000000000..7a13ac0042 --- /dev/null +++ b/debian/patches-rt/0028-rcu-Mark-emergency-sections-in-rcu-stalls.patch @@ -0,0 +1,128 @@ +From: John Ogness <john.ogness@linutronix.de> +Date: Mon, 11 Sep 2023 15:53:39 +0000 +Subject: [PATCH 28/46] rcu: Mark emergency sections in rcu stalls +Origin: https://www.kernel.org/pub/linux/kernel/projects/rt/6.9/older/patches-6.9-rt5.tar.xz + +Mark emergency sections wherever multiple lines of +rcu stall information are generated. In an emergency +section the CPU will not perform console output for the +printk() calls. Instead, a flushing of the console +output is triggered when exiting the emergency section. +This allows the full message block to be stored as +quickly as possible in the ringbuffer. + +Signed-off-by: John Ogness <john.ogness@linutronix.de> +Signed-off-by: Sebastian Andrzej Siewior <bigeasy@linutronix.de> +--- + kernel/rcu/tree_exp.h | 9 +++++++++ + kernel/rcu/tree_stall.h | 11 +++++++++++ + 2 files changed, 20 insertions(+) + +--- a/kernel/rcu/tree_exp.h ++++ b/kernel/rcu/tree_exp.h +@@ -7,6 +7,7 @@ + * Authors: Paul E. McKenney <paulmck@linux.ibm.com> + */ + ++#include <linux/console.h> + #include <linux/lockdep.h> + + static void rcu_exp_handler(void *unused); +@@ -571,6 +572,9 @@ static void synchronize_rcu_expedited_wa + return; + if (rcu_stall_is_suppressed()) + continue; ++ ++ nbcon_cpu_emergency_enter(); ++ + j = jiffies; + rcu_stall_notifier_call_chain(RCU_STALL_NOTIFY_EXP, (void *)(j - jiffies_start)); + trace_rcu_stall_warning(rcu_state.name, TPS("ExpeditedStall")); +@@ -612,6 +616,7 @@ static void synchronize_rcu_expedited_wa + } + pr_cont("\n"); + } ++ nbcon_cpu_emergency_flush(); + rcu_for_each_leaf_node(rnp) { + for_each_leaf_node_possible_cpu(rnp, cpu) { + mask = leaf_node_cpu_bit(rnp, cpu); +@@ -624,6 +629,9 @@ static void synchronize_rcu_expedited_wa + rcu_exp_print_detail_task_stall_rnp(rnp); + } + jiffies_stall = 3 * rcu_exp_jiffies_till_stall_check() + 3; ++ ++ nbcon_cpu_emergency_exit(); ++ + panic_on_rcu_stall(); + } + } +@@ -792,6 +800,7 @@ static void rcu_exp_print_detail_task_st + */ + touch_nmi_watchdog(); + sched_show_task(t); ++ nbcon_cpu_emergency_flush(); + } + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } +--- a/kernel/rcu/tree_stall.h ++++ b/kernel/rcu/tree_stall.h +@@ -7,6 +7,7 @@ + * Author: Paul E. McKenney <paulmck@linux.ibm.com> + */ + ++#include <linux/console.h> + #include <linux/kvm_para.h> + #include <linux/rcu_notifier.h> + +@@ -260,6 +261,7 @@ static void rcu_print_detail_task_stall_ + */ + touch_nmi_watchdog(); + sched_show_task(t); ++ nbcon_cpu_emergency_flush(); + } + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + } +@@ -522,6 +524,7 @@ static void print_cpu_stall_info(int cpu + falsepositive ? " (false positive?)" : ""); + + print_cpu_stat_info(cpu); ++ nbcon_cpu_emergency_flush(); + } + + /* Complain about starvation of grace-period kthread. */ +@@ -604,6 +607,8 @@ static void print_other_cpu_stall(unsign + if (rcu_stall_is_suppressed()) + return; + ++ nbcon_cpu_emergency_enter(); ++ + /* + * OK, time to rat on our buddy... + * See Documentation/RCU/stallwarn.rst for info on how to debug +@@ -655,6 +660,8 @@ static void print_other_cpu_stall(unsign + rcu_check_gp_kthread_expired_fqs_timer(); + rcu_check_gp_kthread_starvation(); + ++ nbcon_cpu_emergency_exit(); ++ + panic_on_rcu_stall(); + + rcu_force_quiescent_state(); /* Kick them all. */ +@@ -675,6 +682,8 @@ static void print_cpu_stall(unsigned lon + if (rcu_stall_is_suppressed()) + return; + ++ nbcon_cpu_emergency_enter(); ++ + /* + * OK, time to rat on ourselves... + * See Documentation/RCU/stallwarn.rst for info on how to debug +@@ -703,6 +712,8 @@ static void print_cpu_stall(unsigned lon + jiffies + 3 * rcu_jiffies_till_stall_check() + 3); + raw_spin_unlock_irqrestore_rcu_node(rnp, flags); + ++ nbcon_cpu_emergency_exit(); ++ + panic_on_rcu_stall(); + + /* |