On Tue, Nov 22, 2022 at 12:59:28PM +0100, Frederic Weisbecker wrote: > On Sat, Nov 19, 2022 at 05:25:02PM +0800, Zhen Lei wrote: > > v7 --> v8: > > 1. Change call jiffies64_to_msecs() to call jiffies_to_msecs(). > > 2. Mention that rcupdate.rcu_cpu_stall_cputime overrides > > CONFIG_RCU_CPU_STALL_CPUTIME behaviour in the Kconfig help text. > > 3. Fix a make htmldocs warning, change "|...|" to ":...:". > > > > v6 --> v7: > > 1. Use kcpustat_field() to obtain the cputime. > > 2. Make the output start with "\t" to match other related prints. > > 3. Aligns the output of the last line of RCU stall. > > > > v5 --> v6: > > 1. When there are more than two continuous RCU stallings, correctly handle the > > value of the second and subsequent sampling periods. Update comments and > > document. > > Thanks to Elliott, Robert for the test. > > 2. Change "rcu stall" to "RCU stall". > > > > v4 --> v5: > > 1. Resolve a git am conflict. No code change. > > > > v3 --> v4: > > 1. Rename rcu_cpu_stall_deep_debug to rcu_cpu_stall_cputime. > > > > v2 --> v3: > > 1. Fix the return type of kstat_cpu_irqs_sum() > > 2. Add Kconfig option CONFIG_RCU_CPU_STALL_DEEP_DEBUG and boot parameter > > rcupdate.rcu_cpu_stall_deep_debug. > > 3. Add comments and normalize local variable name > > > > v1 --> v2: > > 1. Fixed a bug in the code. If the rcu stall is detected by another CPU, > > kcpustat_this_cpu cannot be used. > > @@ -451,7 +451,7 @@ static void print_cpu_stat_info(int cpu) > > if (r->gp_seq != rdp->gp_seq) > > return; > > > > - cpustat = kcpustat_this_cpu->cpustat; > > + cpustat = kcpustat_cpu(cpu).cpustat; > > 2. Move the start point of statistics from rcu_stall_kick_kthreads() to > > rcu_implicit_dynticks_qs(), removing the dependency on irq_work. > > > > v1: > > In some extreme cases, such as the I/O pressure test, the CPU usage may > > be 100%, causing RCU stall. In this case, the printed information about > > current is not useful. Displays the number and usage of hard interrupts, > > soft interrupts, and context switches that are generated within half of > > the CPU stall timeout, can help us make a general judgment. In other > > cases, we can preliminarily determine whether an infinite loop occurs > > when local_irq, local_bh or preempt is disabled. > > > > Zhen Lei (6): > > genirq: Fix the return type of kstat_cpu_irqs_sum() > > sched: Add helper kstat_cpu_softirqs_sum() > > sched: Add helper nr_context_switches_cpu() > > rcu: Add RCU stall diagnosis information > > doc: Document CONFIG_RCU_CPU_STALL_CPUTIME=y stall information > > rcu: Align the output of RCU stall > > Reviewed-by: Frederic Weisbecker <frederic@xxxxxxxxxx> Applied, thank you! Thanx, Paul > Thanks! > > > > > Documentation/RCU/stallwarn.rst | 88 +++++++++++++++++++ > > .../admin-guide/kernel-parameters.txt | 6 ++ > > include/linux/kernel_stat.h | 14 ++- > > kernel/rcu/Kconfig.debug | 13 +++ > > kernel/rcu/rcu.h | 1 + > > kernel/rcu/tree.c | 18 ++++ > > kernel/rcu/tree.h | 19 ++++ > > kernel/rcu/tree_stall.h | 35 +++++++- > > kernel/rcu/update.c | 2 + > > kernel/sched/core.c | 5 ++ > > 10 files changed, 198 insertions(+), 3 deletions(-) > > > > -- > > 2.25.1 > >
