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rcu: Remove rsp parameter from rcu_boot_init_percpu_data() and friends 

There now is only one rcu_state structure in a given build of
the Linux kernel, so there is no need to pass it as a parameter
to RCU's functions.  This commit therefore removes the rsp
parameter from rcu_boot_init_percpu_data(), rcu_init_percpu_data(),
rcu_cleanup_dying_idle_cpu(), and rcu_migrate_callbacks().  While in
the neighborhood, line the last three into rcutree_prepare_cpu(),
rcu_report_dead() and rcutree_migrate_callbacks(), respectively.
This also gets rid of the for_each_rcu_flavor() calls that were in
those tree functions.

Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
This commit is contained in:
Paul E. McKenney 2018-07-03 17:22:34 -07:00
parent 8344b871b1
commit 53b46303da
1 changed files with 38 additions and 70 deletions
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108
kernel/rcu/tree.c
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@ -3352,7 +3352,7 @@ static void rcu_init_new_rnp(struct rcu_node *rnp_leaf)
* Do boot-time initialization of a CPU's per-CPU RCU data. * Do boot-time initialization of a CPU's per-CPU RCU data.
*/ */
static void __init static void __init
rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) rcu_boot_init_percpu_data(int cpu)
{ {
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
@ -3361,23 +3361,25 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->dynticks = &per_cpu(rcu_dynticks, cpu); rdp->dynticks = &per_cpu(rcu_dynticks, cpu);
WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != 1); WARN_ON_ONCE(rdp->dynticks->dynticks_nesting != 1);
WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(rdp->dynticks))); WARN_ON_ONCE(rcu_dynticks_in_eqs(rcu_dynticks_snap(rdp->dynticks)));
rdp->rcu_ofl_gp_seq = rsp->gp_seq; rdp->rcu_ofl_gp_seq = rcu_state.gp_seq;
rdp->rcu_ofl_gp_flags = RCU_GP_CLEANED; rdp->rcu_ofl_gp_flags = RCU_GP_CLEANED;
rdp->rcu_onl_gp_seq = rsp->gp_seq; rdp->rcu_onl_gp_seq = rcu_state.gp_seq;
rdp->rcu_onl_gp_flags = RCU_GP_CLEANED; rdp->rcu_onl_gp_flags = RCU_GP_CLEANED;
rdp->cpu = cpu; rdp->cpu = cpu;
rdp->rsp = rsp; rdp->rsp = &rcu_state;
rcu_boot_init_nocb_percpu_data(rdp); rcu_boot_init_nocb_percpu_data(rdp);
} }
/* /*
* Initialize a CPU's per-CPU RCU data. Note that only one online or * Invoked early in the CPU-online process, when pretty much all services
* are available. The incoming CPU is not present.
*
* Initializes a CPU's per-CPU RCU data. Note that only one online or
* offline event can be happening at a given time. Note also that we can * offline event can be happening at a given time. Note also that we can
* accept some slop in the rsp->gp_seq access due to the fact that this * accept some slop in the rsp->gp_seq access due to the fact that this
* CPU cannot possibly have any RCU callbacks in flight yet. * CPU cannot possibly have any RCU callbacks in flight yet.
*/ */
static void int rcutree_prepare_cpu(unsigned int cpu)
rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
{ {
unsigned long flags; unsigned long flags;
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu); struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
@ -3386,7 +3388,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
/* Set up local state, ensuring consistent view of global state. */ /* Set up local state, ensuring consistent view of global state. */
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
rdp->qlen_last_fqs_check = 0; rdp->qlen_last_fqs_check = 0;
rdp->n_force_qs_snap = rsp->n_force_qs; rdp->n_force_qs_snap = rcu_state.n_force_qs;
rdp->blimit = blimit; rdp->blimit = blimit;
if (rcu_segcblist_empty(&rdp->cblist) && /* No early-boot CBs? */ if (rcu_segcblist_empty(&rdp->cblist) && /* No early-boot CBs? */
!init_nocb_callback_list(rdp)) !init_nocb_callback_list(rdp))
@ -3410,21 +3412,8 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp)
rdp->core_needs_qs = false; rdp->core_needs_qs = false;
rdp->rcu_iw_pending = false; rdp->rcu_iw_pending = false;
rdp->rcu_iw_gp_seq = rnp->gp_seq - 1; rdp->rcu_iw_gp_seq = rnp->gp_seq - 1;
trace_rcu_grace_period(rsp->name, rdp->gp_seq, TPS("cpuonl")); trace_rcu_grace_period(rcu_state.name, rdp->gp_seq, TPS("cpuonl"));
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/*
* Invoked early in the CPU-online process, when pretty much all
* services are available. The incoming CPU is not present.
*/
int rcutree_prepare_cpu(unsigned int cpu)
{
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
rcu_init_percpu_data(cpu, rsp);
rcu_prepare_kthreads(cpu); rcu_prepare_kthreads(cpu);
rcu_spawn_all_nocb_kthreads(cpu); rcu_spawn_all_nocb_kthreads(cpu);
@ -3547,37 +3536,9 @@ void rcu_cpu_starting(unsigned int cpu)
} }
#ifdef CONFIG_HOTPLUG_CPU #ifdef CONFIG_HOTPLUG_CPU
/*
* The CPU is exiting the idle loop into the arch_cpu_idle_dead()
* function. We now remove it from the rcu_node tree's ->qsmaskinitnext
* bit masks.
*/
static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp)
{
unsigned long flags;
unsigned long mask;
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */
/* Remove outgoing CPU from mask in the leaf rcu_node structure. */
mask = rdp->grpmask;
spin_lock(&rsp->ofl_lock);
raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */
rdp->rcu_ofl_gp_seq = READ_ONCE(rsp->gp_seq);
rdp->rcu_ofl_gp_flags = READ_ONCE(rsp->gp_flags);
if (rnp->qsmask & mask) { /* RCU waiting on outgoing CPU? */
/* Report quiescent state -before- changing ->qsmaskinitnext! */
rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
raw_spin_lock_irqsave_rcu_node(rnp, flags);
}
rnp->qsmaskinitnext &= ~mask;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
spin_unlock(&rsp->ofl_lock);
}
/* /*
* The outgoing function has no further need of RCU, so remove it from * The outgoing function has no further need of RCU, so remove it from
* the list of CPUs that RCU must track. * the rcu_node tree's ->qsmaskinitnext bit masks.
* *
* Note that this function is special in that it is invoked directly * Note that this function is special in that it is invoked directly
* from the outgoing CPU rather than from the cpuhp_step mechanism. * from the outgoing CPU rather than from the cpuhp_step mechanism.
@ -3585,21 +3546,41 @@ static void rcu_cleanup_dying_idle_cpu(int cpu, struct rcu_state *rsp)
*/ */
void rcu_report_dead(unsigned int cpu) void rcu_report_dead(unsigned int cpu)
{ {
struct rcu_state *rsp; unsigned long flags;
unsigned long mask;
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
struct rcu_node *rnp = rdp->mynode; /* Outgoing CPU's rdp & rnp. */
/* QS for any half-done expedited RCU-sched GP. */ /* QS for any half-done expedited RCU-sched GP. */
preempt_disable(); preempt_disable();
rcu_report_exp_rdp(&rcu_state, this_cpu_ptr(&rcu_data)); rcu_report_exp_rdp(&rcu_state, this_cpu_ptr(&rcu_data));
preempt_enable(); preempt_enable();
rcu_preempt_deferred_qs(current); rcu_preempt_deferred_qs(current);
for_each_rcu_flavor(rsp)
rcu_cleanup_dying_idle_cpu(cpu, rsp); /* Remove outgoing CPU from mask in the leaf rcu_node structure. */
mask = rdp->grpmask;
spin_lock(&rcu_state.ofl_lock);
raw_spin_lock_irqsave_rcu_node(rnp, flags); /* Enforce GP memory-order guarantee. */
rdp->rcu_ofl_gp_seq = READ_ONCE(rcu_state.gp_seq);
rdp->rcu_ofl_gp_flags = READ_ONCE(rcu_state.gp_flags);
if (rnp->qsmask & mask) { /* RCU waiting on outgoing CPU? */
/* Report quiescent state -before- changing ->qsmaskinitnext! */
rcu_report_qs_rnp(mask, rnp, rnp->gp_seq, flags);
raw_spin_lock_irqsave_rcu_node(rnp, flags);
}
rnp->qsmaskinitnext &= ~mask;
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
spin_unlock(&rcu_state.ofl_lock);
per_cpu(rcu_cpu_started, cpu) = 0; per_cpu(rcu_cpu_started, cpu) = 0;
} }
/* Migrate the dead CPU's callbacks to the current CPU. */ /*
static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp) * The outgoing CPU has just passed through the dying-idle state, and we
* are being invoked from the CPU that was IPIed to continue the offline
* operation. Migrate the outgoing CPU's callbacks to the current CPU.
*/
void rcutree_migrate_callbacks(int cpu)
{ {
unsigned long flags; unsigned long flags;
struct rcu_data *my_rdp; struct rcu_data *my_rdp;
@ -3632,19 +3613,6 @@ static void rcu_migrate_callbacks(int cpu, struct rcu_state *rsp)
cpu, rcu_segcblist_n_cbs(&rdp->cblist), cpu, rcu_segcblist_n_cbs(&rdp->cblist),
rcu_segcblist_first_cb(&rdp->cblist)); rcu_segcblist_first_cb(&rdp->cblist));
} }
/*
* The outgoing CPU has just passed through the dying-idle state,
* and we are being invoked from the CPU that was IPIed to continue the
* offline operation. We need to migrate the outgoing CPU's callbacks.
*/
void rcutree_migrate_callbacks(int cpu)
{
struct rcu_state *rsp;
for_each_rcu_flavor(rsp)
rcu_migrate_callbacks(cpu, rsp);
}
#endif #endif
/* /*
@ -3814,7 +3782,7 @@ static void __init rcu_init_one(struct rcu_state *rsp)
while (i > rnp->grphi) while (i > rnp->grphi)
rnp++; rnp++;
per_cpu_ptr(&rcu_data, i)->mynode = rnp; per_cpu_ptr(&rcu_data, i)->mynode = rnp;
rcu_boot_init_percpu_data(i, rsp); rcu_boot_init_percpu_data(i);
} }
list_add(&rsp->flavors, &rcu_struct_flavors); list_add(&rsp->flavors, &rcu_struct_flavors);
} }