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| author | Paul E. McKenney <paul.mckenney@linaro.org> | 2012-03-01 13:18:08 -0800 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2012-05-09 14:27:54 -0700 |
| commit | b1420f1c8bfc30ecf6380a31d0f686884834b599 (patch) | |
| tree | 56eb378bcd64175a7302a1031b388ecf569a30bb /kernel/rcutree_trace.c | |
| parent | 98248a0e24327bc64eb7518145c44bff7bebebc3 (diff) | |
| download | linux-b1420f1c8bfc30ecf6380a31d0f686884834b599.tar.gz linux-b1420f1c8bfc30ecf6380a31d0f686884834b599.tar.bz2 linux-b1420f1c8bfc30ecf6380a31d0f686884834b599.zip | |
rcu: Make rcu_barrier() less disruptive
The rcu_barrier() primitive interrupts each and every CPU, registering
a callback on every CPU. Once all of these callbacks have been invoked,
rcu_barrier() knows that every callback that was registered before
the call to rcu_barrier() has also been invoked.
However, there is no point in registering a callback on a CPU that
currently has no callbacks, most especially if that CPU is in a
deep idle state. This commit therefore makes rcu_barrier() avoid
interrupting CPUs that have no callbacks. Doing this requires reworking
the handling of orphaned callbacks, otherwise callbacks could slip through
rcu_barrier()'s net by being orphaned from a CPU that rcu_barrier() had
not yet interrupted to a CPU that rcu_barrier() had already interrupted.
This reworking was needed anyway to take a first step towards weaning
RCU from the CPU_DYING notifier's use of stop_cpu().
Signed-off-by: Paul E. McKenney <paul.mckenney@linaro.org>
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcutree_trace.c')
| -rw-r--r-- | kernel/rcutree_trace.c | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/kernel/rcutree_trace.c b/kernel/rcutree_trace.c index ed459edeff43..d4bc16ddd1d4 100644 --- a/kernel/rcutree_trace.c +++ b/kernel/rcutree_trace.c @@ -271,13 +271,13 @@ static void print_one_rcu_state(struct seq_file *m, struct rcu_state *rsp) gpnum = rsp->gpnum; seq_printf(m, "c=%lu g=%lu s=%d jfq=%ld j=%x " - "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu\n", + "nfqs=%lu/nfqsng=%lu(%lu) fqlh=%lu oqlen=%ld/%ld\n", rsp->completed, gpnum, rsp->fqs_state, (long)(rsp->jiffies_force_qs - jiffies), (int)(jiffies & 0xffff), rsp->n_force_qs, rsp->n_force_qs_ngp, rsp->n_force_qs - rsp->n_force_qs_ngp, - rsp->n_force_qs_lh); + rsp->n_force_qs_lh, rsp->qlen_lazy, rsp->qlen); for (rnp = &rsp->node[0]; rnp - &rsp->node[0] < NUM_RCU_NODES; rnp++) { if (rnp->level != level) { seq_puts(m, "\n"); |