diff options
| -rw-r--r-- | kernel/rcu/tree.c | 19 | ||||
| -rw-r--r-- | kernel/rcu/tree.h | 1 |
2 files changed, 16 insertions, 4 deletions
diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index c88240a685ec..0132bc6152dd 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -1624,12 +1624,16 @@ static bool rcu_gp_fqs_check_wake(int *gfp) { struct rcu_node *rnp = rcu_get_root(); - /* Someone like call_rcu() requested a force-quiescent-state scan. */ + // If under overload conditions, force an immediate FQS scan. + if (*gfp & RCU_GP_FLAG_OVLD) + return true; + + // Someone like call_rcu() requested a force-quiescent-state scan. *gfp = READ_ONCE(rcu_state.gp_flags); if (*gfp & RCU_GP_FLAG_FQS) return true; - /* The current grace period has completed. */ + // The current grace period has completed. if (!READ_ONCE(rnp->qsmask) && !rcu_preempt_blocked_readers_cgp(rnp)) return true; @@ -1667,13 +1671,15 @@ static void rcu_gp_fqs(bool first_time) static void rcu_gp_fqs_loop(void) { bool first_gp_fqs; - int gf; + int gf = 0; unsigned long j; int ret; struct rcu_node *rnp = rcu_get_root(); first_gp_fqs = true; j = READ_ONCE(jiffies_till_first_fqs); + if (rcu_state.cbovld) + gf = RCU_GP_FLAG_OVLD; ret = 0; for (;;) { if (!ret) { @@ -1698,7 +1704,11 @@ static void rcu_gp_fqs_loop(void) trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, TPS("fqsstart")); rcu_gp_fqs(first_gp_fqs); - first_gp_fqs = false; + gf = 0; + if (first_gp_fqs) { + first_gp_fqs = false; + gf = rcu_state.cbovld ? RCU_GP_FLAG_OVLD : 0; + } trace_rcu_grace_period(rcu_state.name, rcu_state.gp_seq, TPS("fqsend")); cond_resched_tasks_rcu_qs(); @@ -1718,6 +1728,7 @@ static void rcu_gp_fqs_loop(void) j = 1; else j = rcu_state.jiffies_force_qs - j; + gf = 0; } } } diff --git a/kernel/rcu/tree.h b/kernel/rcu/tree.h index 9dc2ec021da5..44edd0a98ffe 100644 --- a/kernel/rcu/tree.h +++ b/kernel/rcu/tree.h @@ -359,6 +359,7 @@ struct rcu_state { /* Values for rcu_state structure's gp_flags field. */ #define RCU_GP_FLAG_INIT 0x1 /* Need grace-period initialization. */ #define RCU_GP_FLAG_FQS 0x2 /* Need grace-period quiescent-state forcing. */ +#define RCU_GP_FLAG_OVLD 0x4 /* Experiencing callback overload. */ /* Values for rcu_state structure's gp_state field. */ #define RCU_GP_IDLE 0 /* Initial state and no GP in progress. */ |