diff options
Diffstat (limited to 'kernel')
| -rw-r--r-- | kernel/rcutree.c | 66 | ||||
| -rw-r--r-- | kernel/rcutree.h | 3 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 12 |
3 files changed, 45 insertions, 36 deletions
diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 4ca7e02..a9f5103 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -740,11 +740,13 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) } /* - * Clean up after the prior grace period and let rcu_start_gp() start up - * the next grace period if one is needed. Note that the caller must - * hold rnp->lock, as required by rcu_start_gp(), which will release it. + * Report a full set of quiescent states to the specified rcu_state + * data structure. This involves cleaning up after the prior grace + * period and letting rcu_start_gp() start up the next grace period + * if one is needed. Note that the caller must hold rnp->lock, as + * required by rcu_start_gp(), which will release it. */ -static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) +static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) __releases(rcu_get_root(rsp)->lock) { WARN_ON_ONCE(!rcu_gp_in_progress(rsp)); @@ -754,15 +756,16 @@ static void cpu_quiet_msk_finish(struct rcu_state *rsp, unsigned long flags) } /* - * Similar to cpu_quiet(), for which it is a helper function. Allows - * a group of CPUs to be quieted at one go, though all the CPUs in the - * group must be represented by the same leaf rcu_node structure. - * That structure's lock must be held upon entry, and it is released - * before return. + * Similar to rcu_report_qs_rdp(), for which it is a helper function. + * Allows quiescent states for a group of CPUs to be reported at one go + * to the specified rcu_node structure, though all the CPUs in the group + * must be represented by the same rcu_node structure (which need not be + * a leaf rcu_node structure, though it often will be). That structure's + * lock must be held upon entry, and it is released before return. */ static void -cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, - unsigned long flags) +rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, + struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { struct rcu_node *rnp_c; @@ -798,21 +801,23 @@ cpu_quiet_msk(unsigned long mask, struct rcu_state *rsp, struct rcu_node *rnp, /* * Get here if we are the last CPU to pass through a quiescent - * state for this grace period. Invoke cpu_quiet_msk_finish() + * state for this grace period. Invoke rcu_report_qs_rsp() * to clean up and start the next grace period if one is needed. */ - cpu_quiet_msk_finish(rsp, flags); /* releases rnp->lock. */ + rcu_report_qs_rsp(rsp, flags); /* releases rnp->lock. */ } /* - * Record a quiescent state for the specified CPU, which must either be - * the current CPU. The lastcomp argument is used to make sure we are - * still in the grace period of interest. We don't want to end the current - * grace period based on quiescent states detected in an earlier grace - * period! + * Record a quiescent state for the specified CPU to that CPU's rcu_data + * structure. This must be either called from the specified CPU, or + * called when the specified CPU is known to be offline (and when it is + * also known that no other CPU is concurrently trying to help the offline + * CPU). The lastcomp argument is used to make sure we are still in the + * grace period of interest. We don't want to end the current grace period + * based on quiescent states detected in an earlier grace period! */ static void -cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) +rcu_report_qs_rdp(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) { unsigned long flags; unsigned long mask; @@ -827,8 +832,8 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) * The race with GP start is resolved by the fact that we * hold the leaf rcu_node lock, so that the per-CPU bits * cannot yet be initialized -- so we would simply find our - * CPU's bit already cleared in cpu_quiet_msk() if this race - * occurred. + * CPU's bit already cleared in rcu_report_qs_rnp() if this + * race occurred. */ rdp->passed_quiesc = 0; /* try again later! */ spin_unlock_irqrestore(&rnp->lock, flags); @@ -846,7 +851,7 @@ cpu_quiet(int cpu, struct rcu_state *rsp, struct rcu_data *rdp, long lastcomp) */ rdp->nxttail[RCU_NEXT_READY_TAIL] = rdp->nxttail[RCU_NEXT_TAIL]; - cpu_quiet_msk(mask, rsp, rnp, flags); /* releases rnp->lock */ + rcu_report_qs_rnp(mask, rsp, rnp, flags); /* rlses rnp->lock */ } } @@ -877,8 +882,11 @@ rcu_check_quiescent_state(struct rcu_state *rsp, struct rcu_data *rdp) if (!rdp->passed_quiesc) return; - /* Tell RCU we are done (but cpu_quiet() will be the judge of that). */ - cpu_quiet(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed); + /* + * Tell RCU we are done (but rcu_report_qs_rdp() will be the + * judge of that). + */ + rcu_report_qs_rdp(rdp->cpu, rsp, rdp, rdp->passed_quiesc_completed); } #ifdef CONFIG_HOTPLUG_CPU @@ -968,13 +976,13 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) /* * We still hold the leaf rcu_node structure lock here, and * irqs are still disabled. The reason for this subterfuge is - * because invoking task_quiet() with ->onofflock held leads - * to deadlock. + * because invoking rcu_report_unblock_qs_rnp() with ->onofflock + * held leads to deadlock. */ spin_unlock(&rsp->onofflock); /* irqs remain disabled. */ rnp = rdp->mynode; if (need_quiet) - task_quiet(rnp, flags); + rcu_report_unblock_qs_rnp(rnp, flags); else spin_unlock_irqrestore(&rnp->lock, flags); @@ -1164,8 +1172,8 @@ static int rcu_process_dyntick(struct rcu_state *rsp, long lastcomp, } if (mask != 0 && rnp->completed == lastcomp) { - /* cpu_quiet_msk() releases rnp->lock. */ - cpu_quiet_msk(mask, rsp, rnp, flags); + /* rcu_report_qs_rnp() releases rnp->lock. */ + rcu_report_qs_rnp(mask, rsp, rnp, flags); continue; } spin_unlock_irqrestore(&rnp->lock, flags); diff --git a/kernel/rcutree.h b/kernel/rcutree.h index a81188c..8bb03cb 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -306,7 +306,8 @@ long rcu_batches_completed(void); static void rcu_preempt_note_context_switch(int cpu); static int rcu_preempted_readers(struct rcu_node *rnp); #ifdef CONFIG_HOTPLUG_CPU -static void task_quiet(struct rcu_node *rnp, unsigned long flags); +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, + unsigned long flags); #endif /* #ifdef CONFIG_HOTPLUG_CPU */ #ifdef CONFIG_RCU_CPU_STALL_DETECTOR static void rcu_print_task_stall(struct rcu_node *rnp); diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 1d295c7..c9f0c97 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -167,7 +167,7 @@ static int rcu_preempted_readers(struct rcu_node *rnp) * irqs disabled, and this lock is released upon return, but irqs remain * disabled. */ -static void task_quiet(struct rcu_node *rnp, unsigned long flags) +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) __releases(rnp->lock) { unsigned long mask; @@ -185,7 +185,7 @@ static void task_quiet(struct rcu_node *rnp, unsigned long flags) * or tasks were kicked up to root rcu_node due to * CPUs going offline. */ - cpu_quiet_msk_finish(&rcu_preempt_state, flags); + rcu_report_qs_rsp(&rcu_preempt_state, flags); return; } @@ -193,7 +193,7 @@ static void task_quiet(struct rcu_node *rnp, unsigned long flags) mask = rnp->grpmask; spin_unlock(&rnp->lock); /* irqs remain disabled. */ spin_lock(&rnp_p->lock); /* irqs already disabled. */ - cpu_quiet_msk(mask, &rcu_preempt_state, rnp_p, flags); + rcu_report_qs_rnp(mask, &rcu_preempt_state, rnp_p, flags); } /* @@ -253,12 +253,12 @@ static void rcu_read_unlock_special(struct task_struct *t) /* * If this was the last task on the current list, and if * we aren't waiting on any CPUs, report the quiescent state. - * Note that task_quiet() releases rnp->lock. + * Note that rcu_report_unblock_qs_rnp() releases rnp->lock. */ if (empty) spin_unlock_irqrestore(&rnp->lock, flags); else - task_quiet(rnp, flags); + rcu_report_unblock_qs_rnp(rnp, flags); } else { local_irq_restore(flags); } @@ -566,7 +566,7 @@ static int rcu_preempted_readers(struct rcu_node *rnp) #ifdef CONFIG_HOTPLUG_CPU /* Because preemptible RCU does not exist, no quieting of tasks. */ -static void task_quiet(struct rcu_node *rnp, unsigned long flags) +static void rcu_report_unblock_qs_rnp(struct rcu_node *rnp, unsigned long flags) { spin_unlock_irqrestore(&rnp->lock, flags); } |