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| author | Joel Fernandes (Google) <joel@joelfernandes.org> | 2020-06-18 21:36:40 -0400 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-08-24 18:36:04 -0700 |
| commit | a7886e899fd8334a03d37e66ad10295d175725ea (patch) | |
| tree | 48ba829a0e0a0cedf5f67458a86a0b74d77c4f7e /kernel/rcu | |
| parent | c30068f41a0e899f870e0158a2c69c68d738bf96 (diff) | |
| download | linux-a7886e899fd8334a03d37e66ad10295d175725ea.tar.gz linux-a7886e899fd8334a03d37e66ad10295d175725ea.tar.bz2 linux-a7886e899fd8334a03d37e66ad10295d175725ea.zip | |
rcu/trace: Use gp_seq_req in acceleration's rcu_grace_period tracepoint
During acceleration of CB, the rsp's gp_seq is rcu_seq_snap'd. This is
the value used for acceleration - it is the value of gp_seq at which it
is safe the execute all callbacks in the callback list.
The rdp's gp_seq is not very useful for this scenario. Make
rcu_grace_period report the gp_seq_req instead as it allows one to
reason about how the acceleration works.
Signed-off-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 5 |
1 files changed, 3 insertions, 2 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index eb36779697ca..896912034982 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1483,9 +1483,10 @@ static bool rcu_accelerate_cbs(struct rcu_node *rnp, struct rcu_data *rdp) /* Trace depending on how much we were able to accelerate. */ if (rcu_segcblist_restempty(&rdp->cblist, RCU_WAIT_TAIL)) - trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("AccWaitCB")); + trace_rcu_grace_period(rcu_state.name, gp_seq_req, TPS("AccWaitCB")); else - trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("AccReadyCB")); + trace_rcu_grace_period(rcu_state.name, gp_seq_req, TPS("AccReadyCB")); + return ret; } |