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authorPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-08-05 16:03:54 -0700
committerPaul E. McKenney <paulmck@linux.vnet.ibm.com>2015-09-20 21:16:20 -0700
commitbce5fa12aad148e15efd9bc0015dc4898b6e723b (patch)
tree799e88458d5eda75b2334325777c9ce1bb66d3e6 /kernel/rcu/tree.h
parent8203d6d0ee784cfb2ebf89053f7fe399abc867d7 (diff)
downloadlinux-sh-bce5fa12aad148e15efd9bc0015dc4898b6e723b.tar.gz
rcu: Move synchronize_sched_expedited() to combining tree
Currently, synchronize_sched_expedited() uses a single global counter to track the number of remaining context switches that the current expedited grace period must wait on. This is problematic on large systems, where the resulting memory contention can be pathological. This commit therefore makes synchronize_sched_expedited() instead use the combining tree in the same manner as synchronize_rcu_expedited(), keeping memory contention down to a dull roar. This commit creates a temporary function sync_sched_exp_select_cpus() that is very similar to sync_rcu_exp_select_cpus(). A later commit will consolidate these two functions, which becomes possible when synchronize_sched_expedited() switches from stop_one_cpu_nowait() to smp_call_function_single(). Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Diffstat (limited to 'kernel/rcu/tree.h')
-rw-r--r--kernel/rcu/tree.h1
1 files changed, 0 insertions, 1 deletions
diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h
index a57f25ecca58..efe361c764ab 100644
--- a/kernel/rcu/tree.h
+++ b/kernel/rcu/tree.h
@@ -383,7 +383,6 @@ struct rcu_data {
struct rcu_head oom_head;
#endif /* #ifdef CONFIG_RCU_FAST_NO_HZ */
struct mutex exp_funnel_mutex;
- bool exp_done; /* Expedited QS for this CPU? */
/* 7) Callback offloading. */
#ifdef CONFIG_RCU_NOCB_CPU