Messages in this thread Patch in this message | | | From | "Paul E. McKenney" <> | Subject | [PATCH v2 tip/core/rcu 09/22] rcu: Detect stalls caused by failure to propagate up rcu_node tree | Date | Mon, 16 Mar 2015 11:37:53 -0700 |
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From: "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>
If all CPUs have passed through quiescent states, then stalls might be due to starvation of the grace-period kthread or to failure to propagate the quiescent states up the rcu_node combining tree. The current stall warning messages do not differentiate, so this commit adds a printout of the root rcu_node structure's ->qsmask field.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> --- kernel/rcu/tree.c | 5 +++-- 1 file changed, 3 insertions(+), 2 deletions(-)
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 98da632d1d49..3b7e4133ca99 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1196,9 +1196,10 @@ static void print_other_cpu_stall(struct rcu_state *rsp, unsigned long gpnum) } else { j = jiffies; gpa = ACCESS_ONCE(rsp->gp_activity); - pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld\n", + pr_err("All QSes seen, last %s kthread activity %ld (%ld-%ld), jiffies_till_next_fqs=%ld, root ->qsmask %#lx\n", rsp->name, j - gpa, j, gpa, - jiffies_till_next_fqs); + jiffies_till_next_fqs, + rcu_get_root(rsp)->qsmask); /* In this case, the current CPU might be at fault. */ sched_show_task(current); } -- 1.8.1.5
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