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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-11-17 13:25:21 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2015-12-04 12:26:53 -0800 |
| commit | 72611ab9f5d2d384a04e72d560c9c82463115cbf (patch) | |
| tree | 46daecec76847f22b9cc89f80c222fa027122d04 /kernel/rcu | |
| parent | 73f36f9de8bed78bcda2704a348594c20518b455 (diff) | |
| download | linux-stable-72611ab9f5d2d384a04e72d560c9c82463115cbf.tar.gz linux-stable-72611ab9f5d2d384a04e72d560c9c82463115cbf.tar.bz2 linux-stable-72611ab9f5d2d384a04e72d560c9c82463115cbf.zip | |
rcu: Add more diagnostics to expedited stall warning messages.
This commit adds print statements that check the rcu_node structure to
find which ->expmask bits and which ->exp_tasks structures are blocking
the current expedited grace period.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 24 |
1 files changed, 21 insertions, 3 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index bc6b79716a86..6a652d1f3d7f 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -3745,6 +3745,7 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) unsigned long jiffies_stall; unsigned long jiffies_start; unsigned long mask; + int ndetected; struct rcu_node *rnp; struct rcu_node *rnp_root = rcu_get_root(rsp); int ret; @@ -3767,14 +3768,16 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) } pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {", rsp->name); + ndetected = 0; rcu_for_each_leaf_node(rsp, rnp) { - (void)rcu_print_task_exp_stall(rnp); + ndetected = rcu_print_task_exp_stall(rnp); mask = 1; for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) { struct rcu_data *rdp; if (!(rnp->expmask & mask)) continue; + ndetected++; rdp = per_cpu_ptr(rsp->rda, cpu); pr_cont(" %d-%c%c%c", cpu, "O."[cpu_online(cpu)], @@ -3783,8 +3786,23 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp) } mask <<= 1; } - pr_cont(" } %lu jiffies s: %lu\n", - jiffies - jiffies_start, rsp->expedited_sequence); + pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n", + jiffies - jiffies_start, rsp->expedited_sequence, + rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]); + if (!ndetected) { + pr_err("blocking rcu_node structures:"); + rcu_for_each_node_breadth_first(rsp, rnp) { + if (rnp == rnp_root) + continue; /* printed unconditionally */ + if (sync_rcu_preempt_exp_done(rnp)) + continue; + pr_cont(" l=%u:%d-%d:%#lx/%c", + rnp->level, rnp->grplo, rnp->grphi, + rnp->expmask, + ".T"[!!rnp->exp_tasks]); + } + pr_cont("\n"); + } rcu_for_each_leaf_node(rsp, rnp) { mask = 1; for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++, mask <<= 1) { |