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| author | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-04-23 00:06:05 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@linux.vnet.ibm.com> | 2018-07-12 23:25:17 +0200 |
| commit | 18390aeae7010ee56b132dcfb663ba362a099d99 (patch) | |
| tree | 52282bb131a34abc51599d1aaa71a0da62084f9d | |
| parent | rcu: Diagnostics for grace-period startup hangs (diff) | |
| download | linux-18390aeae7010ee56b132dcfb663ba362a099d99.tar.xz linux-18390aeae7010ee56b132dcfb663ba362a099d99.zip | |
rcu: Make rcu_gp_cleanup() write only once to ->gp_flags
At the end of rcu_gp_cleanup(), if another grace period is needed, but
not via rcu_accelerate_cbs(), the ->gp_flags field is written twice,
once when making the new grace-period request, and once when clearing
all other types of requests. This commit therefore adds an else-clause
to avoid this double write.
Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
| -rw-r--r-- | kernel/rcu/tree.c | 3 |
1 files changed, 2 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 6ce82c009195..a9a4a260ea7d 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2117,8 +2117,9 @@ static void rcu_gp_cleanup(struct rcu_state *rsp) rsp->gp_req_activity = jiffies; trace_rcu_grace_period(rsp->name, READ_ONCE(rsp->gpnum), TPS("newreq")); + } else { + WRITE_ONCE(rsp->gp_flags, rsp->gp_flags & RCU_GP_FLAG_INIT); } - WRITE_ONCE(rsp->gp_flags, rsp->gp_flags & RCU_GP_FLAG_INIT); raw_spin_unlock_irq_rcu_node(rnp); } |