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| author | Neeraj Upadhyay <neeraju@codeaurora.org> | 2020-06-21 20:37:27 +0200 |
|---|---|---|
| committer | Paul E. McKenney <paulmck@kernel.org> | 2020-08-25 03:36:05 +0200 |
| commit | 9c39245382de4d52a122641952900709d4a9950b (patch) | |
| tree | e9d0cc02ee644d531df7269798bffe5db7710bbf /kernel/rcu | |
| parent | nocb: Clarify RCU nocb CPU error message (diff) | |
| download | linux-9c39245382de4d52a122641952900709d4a9950b.tar.xz linux-9c39245382de4d52a122641952900709d4a9950b.zip | |
rcu/tree: Force quiescent state on callback overload
On callback overload, it is necessary to quickly detect idle CPUs,
and rcu_gp_fqs_check_wake() checks for this condition. Unfortunately,
the code following the call to this function does not repeat this check,
which means that in reality no actual quiescent-state forcing, instead
only a couple of quick and pointless wakeups at the beginning of the
grace period.
This commit therefore adds a check for the RCU_GP_FLAG_OVLD flag in
the post-wakeup "if" statement in rcu_gp_fqs_loop().
Fixes: 1fca4d12f4637 ("rcu: Expedite first two FQS scans under callback-overload conditions")
Reviewed-by: Joel Fernandes (Google) <joel@joelfernandes.org>
Signed-off-by: Neeraj Upadhyay <neeraju@codeaurora.org>
Signed-off-by: Paul E. McKenney <paulmck@kernel.org>
Diffstat (limited to 'kernel/rcu')
| -rw-r--r-- | kernel/rcu/tree.c | 2 |
1 files changed, 1 insertions, 1 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 896912034982..4770d7709dc2 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1884,7 +1884,7 @@ static void rcu_gp_fqs_loop(void) break; /* If time for quiescent-state forcing, do it. */ if (!time_after(rcu_state.jiffies_force_qs, jiffies) || - (gf & RCU_GP_FLAG_FQS)) { + (gf & (RCU_GP_FLAG_FQS | RCU_GP_FLAG_OVLD))) { trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, TPS("fqsstart")); rcu_gp_fqs(first_gp_fqs); |