From f22ce09157239aab08eae99c678ef664f71a9097 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Fri, 1 Sep 2017 14:40:54 -0700 Subject: rcu: Suppress RCU CPU stall warnings while dumping trace Currently, RCU emits Suppress RCU CPU stall warnings during its automatically initiated ftrace_dump() calls after detecting an error condition, which can result in excessively excessive console output and lost trace events. This commit therefore suppresses RCU CPU stall warnings across any of these ftrace_dump() calls. Signed-off-by: Paul E. McKenney --- kernel/rcu/rcu.h | 17 +++++++++++++++++ 1 file changed, 17 insertions(+) (limited to 'kernel/rcu/rcu.h') diff --git a/kernel/rcu/rcu.h b/kernel/rcu/rcu.h index b8729eb09a5d..59c471de342a 100644 --- a/kernel/rcu/rcu.h +++ b/kernel/rcu/rcu.h @@ -203,6 +203,21 @@ static inline bool __rcu_reclaim(const char *rn, struct rcu_head *head) extern int rcu_cpu_stall_suppress; int rcu_jiffies_till_stall_check(void); +#define rcu_ftrace_dump_stall_suppress() \ +do { \ + if (!rcu_cpu_stall_suppress) \ + rcu_cpu_stall_suppress = 3; \ +} while (0) + +#define rcu_ftrace_dump_stall_unsuppress() \ +do { \ + if (rcu_cpu_stall_suppress == 3) \ + rcu_cpu_stall_suppress = 0; \ +} while (0) + +#else /* #endif #ifdef CONFIG_RCU_STALL_COMMON */ +#define rcu_ftrace_dump_stall_suppress() +#define rcu_ftrace_dump_stall_unsuppress() #endif /* #ifdef CONFIG_RCU_STALL_COMMON */ /* @@ -222,7 +237,9 @@ do { \ if (!atomic_read(&___rfd_beenhere) && \ !atomic_xchg(&___rfd_beenhere, 1)) { \ tracing_off(); \ + rcu_ftrace_dump_stall_suppress(); \ ftrace_dump(oops_dump_mode); \ + rcu_ftrace_dump_stall_unsuppress(); \ } \ } while (0) -- cgit v1.2.3