diff options
| author | Ingo Molnar <mingo@kernel.org> | 2014-09-03 10:46:51 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-03 10:46:51 +0200 |
| commit | 651bc1a474ad5f3a94587117cf509d7fa9247f69 (patch) | |
| tree | 897e3dd13af15f3224e85ac2e1ca45e0a6ab5ab1 /kernel | |
| parent | 69e273c0b0a3c337a521d083374c918dc52c666f (diff) | |
| parent | 11ed7f934cb807f26da09547b5946c2e534d1dac (diff) | |
| download | linux-651bc1a474ad5f3a94587117cf509d7fa9247f69.tar.bz2 | |
Merge branch 'rcu/urgent' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu into core/urgent
Pull an RCU fix from Paul E. McKenney:
"This series contains a single commit fixing an initialization bug
reported by Amit Shah and fixed by Pranith Kumar (and tested by Amit).
This bug results in a boot-time hang in callback-offloaded configurations
where callbacks were posted before the offloading ('rcuo') kthreads
were created."
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcu/tree.h | 2 | ||||
| -rw-r--r-- | kernel/rcu/tree_plugin.h | 22 |
2 files changed, 12 insertions, 12 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 71e64c718f75..6a86eb7bac45 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -358,7 +358,7 @@ struct rcu_data { struct rcu_head **nocb_gp_tail; long nocb_gp_count; long nocb_gp_count_lazy; - bool nocb_leader_wake; /* Is the nocb leader thread awake? */ + bool nocb_leader_sleep; /* Is the nocb leader thread asleep? */ struct rcu_data *nocb_next_follower; /* Next follower in wakeup chain. */ diff --git a/kernel/rcu/tree_plugin.h b/kernel/rcu/tree_plugin.h index 00dc411e9676..a7997e272564 100644 --- a/kernel/rcu/tree_plugin.h +++ b/kernel/rcu/tree_plugin.h @@ -2074,9 +2074,9 @@ static void wake_nocb_leader(struct rcu_data *rdp, bool force) if (!ACCESS_ONCE(rdp_leader->nocb_kthread)) return; - if (!ACCESS_ONCE(rdp_leader->nocb_leader_wake) || force) { + if (ACCESS_ONCE(rdp_leader->nocb_leader_sleep) || force) { /* Prior xchg orders against prior callback enqueue. */ - ACCESS_ONCE(rdp_leader->nocb_leader_wake) = true; + ACCESS_ONCE(rdp_leader->nocb_leader_sleep) = false; wake_up(&rdp_leader->nocb_wq); } } @@ -2253,7 +2253,7 @@ wait_again: if (!rcu_nocb_poll) { trace_rcu_nocb_wake(my_rdp->rsp->name, my_rdp->cpu, "Sleep"); wait_event_interruptible(my_rdp->nocb_wq, - ACCESS_ONCE(my_rdp->nocb_leader_wake)); + !ACCESS_ONCE(my_rdp->nocb_leader_sleep)); /* Memory barrier handled by smp_mb() calls below and repoll. */ } else if (firsttime) { firsttime = false; /* Don't drown trace log with "Poll"! */ @@ -2292,12 +2292,12 @@ wait_again: schedule_timeout_interruptible(1); /* Rescan in case we were a victim of memory ordering. */ - my_rdp->nocb_leader_wake = false; - smp_mb(); /* Ensure _wake false before scan. */ + my_rdp->nocb_leader_sleep = true; + smp_mb(); /* Ensure _sleep true before scan. */ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) if (ACCESS_ONCE(rdp->nocb_head)) { /* Found CB, so short-circuit next wait. */ - my_rdp->nocb_leader_wake = true; + my_rdp->nocb_leader_sleep = false; break; } goto wait_again; @@ -2307,17 +2307,17 @@ wait_again: rcu_nocb_wait_gp(my_rdp); /* - * We left ->nocb_leader_wake set to reduce cache thrashing. - * We clear it now, but recheck for new callbacks while + * We left ->nocb_leader_sleep unset to reduce cache thrashing. + * We set it now, but recheck for new callbacks while * traversing our follower list. */ - my_rdp->nocb_leader_wake = false; - smp_mb(); /* Ensure _wake false before scan of ->nocb_head. */ + my_rdp->nocb_leader_sleep = true; + smp_mb(); /* Ensure _sleep true before scan of ->nocb_head. */ /* Each pass through the following loop wakes a follower, if needed. */ for (rdp = my_rdp; rdp; rdp = rdp->nocb_next_follower) { if (ACCESS_ONCE(rdp->nocb_head)) - my_rdp->nocb_leader_wake = true; /* No need to wait. */ + my_rdp->nocb_leader_sleep = false;/* No need to sleep.*/ if (!rdp->nocb_gp_head) continue; /* No CBs, so no need to wake follower. */ |