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| author | Paul E. McKenney <paulmck@linux.ibm.com> | 2018-10-03 02:05:46 +0300 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.ibm.com> | 2018-12-01 23:45:37 +0300 |
| commit | 903ee83d91776bc72d856147743687d4b6c99286 (patch) | |
| tree | df3216d4cc5154d397a4acbcbe6d04ddb4ae32b4 /kernel/rcu/tree.c | |
| parent | e0aff97355575ac6a28a48a4217533a3953095c5 (diff) | |
| download | linux-903ee83d91776bc72d856147743687d4b6c99286.tar.xz | |
rcu: Account for nocb-CPU callback counts in RCU CPU stall warnings
The RCU CPU stall warnings print an estimate of the total number of
RCU callbacks queued in the system, but this estimate leaves out
the callbacks queued for nocbs CPUs. This commit therefore introduces
rcu_get_n_cbs_cpu(), which gives an accurate callback estimate for
both nocbs and normal CPUs, and uses this new function as needed.
This commit also introduces a rcu_get_n_cbs_nocb_cpu() helper function
that returns the number of callbacks for nocbs CPUs or zero otherwise,
and also uses this function in place of direct access to ->nocb_q_count
while in the area (fewer characters, you see).
Signed-off-by: Paul E. McKenney <paulmck@linux.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.c')
| -rw-r--r-- | kernel/rcu/tree.c | 19 |
1 files changed, 15 insertions, 4 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 853b79a6ff10..0933d8650890 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -207,6 +207,19 @@ static int rcu_gp_in_progress(void) return rcu_seq_state(rcu_seq_current(&rcu_state.gp_seq)); } +/* + * Return the number of callbacks queued on the specified CPU. + * Handles both the nocbs and normal cases. + */ +static long rcu_get_n_cbs_cpu(int cpu) +{ + struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); + + if (rcu_segcblist_is_enabled(&rdp->cblist)) /* Online normal CPU? */ + return rcu_segcblist_n_cbs(&rdp->cblist); + return rcu_get_n_cbs_nocb_cpu(rdp); /* Works for offline, too. */ +} + void rcu_softirq_qs(void) { rcu_qs(); @@ -1265,8 +1278,7 @@ static void print_other_cpu_stall(unsigned long gp_seq) print_cpu_stall_info_end(); for_each_possible_cpu(cpu) - totqlen += rcu_segcblist_n_cbs(&per_cpu_ptr(&rcu_data, - cpu)->cblist); + totqlen += rcu_get_n_cbs_cpu(cpu); pr_cont("(detected by %d, t=%ld jiffies, g=%ld, q=%lu)\n", smp_processor_id(), (long)(jiffies - rcu_state.gp_start), (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); @@ -1326,8 +1338,7 @@ static void print_cpu_stall(void) raw_spin_unlock_irqrestore_rcu_node(rdp->mynode, flags); print_cpu_stall_info_end(); for_each_possible_cpu(cpu) - totqlen += rcu_segcblist_n_cbs(&per_cpu_ptr(&rcu_data, - cpu)->cblist); + totqlen += rcu_get_n_cbs_cpu(cpu); pr_cont(" (t=%lu jiffies g=%ld q=%lu)\n", jiffies - rcu_state.gp_start, (long)rcu_seq_current(&rcu_state.gp_seq), totqlen); |