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rcu: Remove rsp parameter from expedited grace-period functions 

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 the code in kernel/rcu/tree_exp.h, and removes all of the
rsp local variables while in the area.

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
Родитель 4580b0541b
Коммит 63d4c8c979
4 изменённых файлов: 94 добавлений и 109 удалений
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4
kernel/rcu/tree.c
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@ -139,7 +139,7 @@ static void rcu_cleanup_dead_rnp(struct rcu_node *rnp_leaf);
static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu); static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu);
static void invoke_rcu_core(void); static void invoke_rcu_core(void);
static void invoke_rcu_callbacks(struct rcu_data *rdp); static void invoke_rcu_callbacks(struct rcu_data *rdp);
static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp); static void rcu_report_exp_rdp(struct rcu_data *rdp);
static void sync_sched_exp_online_cleanup(int cpu); static void sync_sched_exp_online_cleanup(int cpu);
/* rcuc/rcub kthread realtime priority */ /* rcuc/rcub kthread realtime priority */
@ -3553,7 +3553,7 @@ void rcu_report_dead(unsigned int cpu)
/* 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(this_cpu_ptr(&rcu_data));
preempt_enable(); preempt_enable();
rcu_preempt_deferred_qs(current); rcu_preempt_deferred_qs(current);

1
kernel/rcu/tree.h
Просмотреть файл

@ -61,7 +61,6 @@ struct rcu_dynticks {
/* Communicate arguments to a workqueue handler. */ /* Communicate arguments to a workqueue handler. */
struct rcu_exp_work { struct rcu_exp_work {
smp_call_func_t rew_func; smp_call_func_t rew_func;
struct rcu_state *rew_rsp;
unsigned long rew_s; unsigned long rew_s;
struct work_struct rew_work; struct work_struct rew_work;
}; };

185
kernel/rcu/tree_exp.h
Просмотреть файл

@ -25,39 +25,39 @@
/* /*
* Record the start of an expedited grace period. * Record the start of an expedited grace period.
*/ */
static void rcu_exp_gp_seq_start(struct rcu_state *rsp) static void rcu_exp_gp_seq_start(void)
{ {
rcu_seq_start(&rsp->expedited_sequence); rcu_seq_start(&rcu_state.expedited_sequence);
} }
/* /*
* Return then value that expedited-grace-period counter will have * Return then value that expedited-grace-period counter will have
* at the end of the current grace period. * at the end of the current grace period.
*/ */
static __maybe_unused unsigned long rcu_exp_gp_seq_endval(struct rcu_state *rsp) static __maybe_unused unsigned long rcu_exp_gp_seq_endval(void)
{ {
return rcu_seq_endval(&rsp->expedited_sequence); return rcu_seq_endval(&rcu_state.expedited_sequence);
} }
/* /*
* Record the end of an expedited grace period. * Record the end of an expedited grace period.
*/ */
static void rcu_exp_gp_seq_end(struct rcu_state *rsp) static void rcu_exp_gp_seq_end(void)
{ {
rcu_seq_end(&rsp->expedited_sequence); rcu_seq_end(&rcu_state.expedited_sequence);
smp_mb(); /* Ensure that consecutive grace periods serialize. */ smp_mb(); /* Ensure that consecutive grace periods serialize. */
} }
/* /*
* Take a snapshot of the expedited-grace-period counter. * Take a snapshot of the expedited-grace-period counter.
*/ */
static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp) static unsigned long rcu_exp_gp_seq_snap(void)
{ {
unsigned long s; unsigned long s;
smp_mb(); /* Caller's modifications seen first by other CPUs. */ smp_mb(); /* Caller's modifications seen first by other CPUs. */
s = rcu_seq_snap(&rsp->expedited_sequence); s = rcu_seq_snap(&rcu_state.expedited_sequence);
trace_rcu_exp_grace_period(rsp->name, s, TPS("snap")); trace_rcu_exp_grace_period(rcu_state.name, s, TPS("snap"));
return s; return s;
} }
@ -66,9 +66,9 @@ static unsigned long rcu_exp_gp_seq_snap(struct rcu_state *rsp)
* if a full expedited grace period has elapsed since that snapshot * if a full expedited grace period has elapsed since that snapshot
* was taken. * was taken.
*/ */
static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s) static bool rcu_exp_gp_seq_done(unsigned long s)
{ {
return rcu_seq_done(&rsp->expedited_sequence, s); return rcu_seq_done(&rcu_state.expedited_sequence, s);
} }
/* /*
@ -78,26 +78,26 @@ static bool rcu_exp_gp_seq_done(struct rcu_state *rsp, unsigned long s)
* ever been online. This means that this function normally takes its * ever been online. This means that this function normally takes its
* no-work-to-do fastpath. * no-work-to-do fastpath.
*/ */
static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp) static void sync_exp_reset_tree_hotplug(void)
{ {
bool done; bool done;
unsigned long flags; unsigned long flags;
unsigned long mask; unsigned long mask;
unsigned long oldmask; unsigned long oldmask;
int ncpus = smp_load_acquire(&rsp->ncpus); /* Order against locking. */ int ncpus = smp_load_acquire(&rcu_state.ncpus); /* Order vs. locking. */
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_node *rnp_up; struct rcu_node *rnp_up;
/* If no new CPUs onlined since last time, nothing to do. */ /* If no new CPUs onlined since last time, nothing to do. */
if (likely(ncpus == rsp->ncpus_snap)) if (likely(ncpus == rcu_state.ncpus_snap))
return; return;
rsp->ncpus_snap = ncpus; rcu_state.ncpus_snap = ncpus;
/* /*
* Each pass through the following loop propagates newly onlined * Each pass through the following loop propagates newly onlined
* CPUs for the current rcu_node structure up the rcu_node tree. * CPUs for the current rcu_node structure up the rcu_node tree.
*/ */
rcu_for_each_leaf_node(rsp, rnp) { rcu_for_each_leaf_node(&rcu_state, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
if (rnp->expmaskinit == rnp->expmaskinitnext) { if (rnp->expmaskinit == rnp->expmaskinitnext) {
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
@ -135,13 +135,13 @@ static void sync_exp_reset_tree_hotplug(struct rcu_state *rsp)
* Reset the ->expmask values in the rcu_node tree in preparation for * Reset the ->expmask values in the rcu_node tree in preparation for
* a new expedited grace period. * a new expedited grace period.
*/ */
static void __maybe_unused sync_exp_reset_tree(struct rcu_state *rsp) static void __maybe_unused sync_exp_reset_tree(void)
{ {
unsigned long flags; unsigned long flags;
struct rcu_node *rnp; struct rcu_node *rnp;
sync_exp_reset_tree_hotplug(rsp); sync_exp_reset_tree_hotplug();
rcu_for_each_node_breadth_first(rsp, rnp) { rcu_for_each_node_breadth_first(&rcu_state, rnp) {
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
WARN_ON_ONCE(rnp->expmask); WARN_ON_ONCE(rnp->expmask);
rnp->expmask = rnp->expmaskinit; rnp->expmask = rnp->expmaskinit;
@ -194,7 +194,7 @@ static bool sync_rcu_preempt_exp_done_unlocked(struct rcu_node *rnp)
* *
* Caller must hold the specified rcu_node structure's ->lock. * Caller must hold the specified rcu_node structure's ->lock.
*/ */
static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, static void __rcu_report_exp_rnp(struct rcu_node *rnp,
bool wake, unsigned long flags) bool wake, unsigned long flags)
__releases(rnp->lock) __releases(rnp->lock)
{ {
@ -212,7 +212,7 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
if (wake) { if (wake) {
smp_mb(); /* EGP done before wake_up(). */ smp_mb(); /* EGP done before wake_up(). */
swake_up_one(&rsp->expedited_wq); swake_up_one(&rcu_state.expedited_wq);
} }
break; break;
} }
@ -229,20 +229,19 @@ static void __rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp,
* Report expedited quiescent state for specified node. This is a * Report expedited quiescent state for specified node. This is a
* lock-acquisition wrapper function for __rcu_report_exp_rnp(). * lock-acquisition wrapper function for __rcu_report_exp_rnp().
*/ */
static void __maybe_unused rcu_report_exp_rnp(struct rcu_state *rsp, static void __maybe_unused rcu_report_exp_rnp(struct rcu_node *rnp, bool wake)
struct rcu_node *rnp, bool wake)
{ {
unsigned long flags; unsigned long flags;
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
__rcu_report_exp_rnp(rsp, rnp, wake, flags); __rcu_report_exp_rnp(rnp, wake, flags);
} }
/* /*
* Report expedited quiescent state for multiple CPUs, all covered by the * Report expedited quiescent state for multiple CPUs, all covered by the
* specified leaf rcu_node structure. * specified leaf rcu_node structure.
*/ */
static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp, static void rcu_report_exp_cpu_mult(struct rcu_node *rnp,
unsigned long mask, bool wake) unsigned long mask, bool wake)
{ {
unsigned long flags; unsigned long flags;
@ -253,23 +252,23 @@ static void rcu_report_exp_cpu_mult(struct rcu_state *rsp, struct rcu_node *rnp,
return; return;
} }
rnp->expmask &= ~mask; rnp->expmask &= ~mask;
__rcu_report_exp_rnp(rsp, rnp, wake, flags); /* Releases rnp->lock. */ __rcu_report_exp_rnp(rnp, wake, flags); /* Releases rnp->lock. */
} }
/* /*
* Report expedited quiescent state for specified rcu_data (CPU). * Report expedited quiescent state for specified rcu_data (CPU).
*/ */
static void rcu_report_exp_rdp(struct rcu_state *rsp, struct rcu_data *rdp) static void rcu_report_exp_rdp(struct rcu_data *rdp)
{ {
WRITE_ONCE(rdp->deferred_qs, false); WRITE_ONCE(rdp->deferred_qs, false);
rcu_report_exp_cpu_mult(rsp, rdp->mynode, rdp->grpmask, true); rcu_report_exp_cpu_mult(rdp->mynode, rdp->grpmask, true);
} }
/* Common code for work-done checking. */ /* Common code for work-done checking. */
static bool sync_exp_work_done(struct rcu_state *rsp, unsigned long s) static bool sync_exp_work_done(unsigned long s)
{ {
if (rcu_exp_gp_seq_done(rsp, s)) { if (rcu_exp_gp_seq_done(s)) {
trace_rcu_exp_grace_period(rsp->name, s, TPS("done")); trace_rcu_exp_grace_period(rcu_state.name, s, TPS("done"));
/* Ensure test happens before caller kfree(). */ /* Ensure test happens before caller kfree(). */
smp_mb__before_atomic(); /* ^^^ */ smp_mb__before_atomic(); /* ^^^ */
return true; return true;
@ -284,7 +283,7 @@ static bool sync_exp_work_done(struct rcu_state *rsp, unsigned long s)
* with the mutex held, indicating that the caller must actually do the * with the mutex held, indicating that the caller must actually do the
* expedited grace period. * expedited grace period.
*/ */
static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s) static bool exp_funnel_lock(unsigned long s)
{ {
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id()); struct rcu_data *rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
struct rcu_node *rnp = rdp->mynode; struct rcu_node *rnp = rdp->mynode;
@ -294,18 +293,18 @@ static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) && if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s) &&
(rnp == rnp_root || (rnp == rnp_root ||
ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) && ULONG_CMP_LT(READ_ONCE(rnp_root->exp_seq_rq), s)) &&
mutex_trylock(&rsp->exp_mutex)) mutex_trylock(&rcu_state.exp_mutex))
goto fastpath; goto fastpath;
/* /*
* Each pass through the following loop works its way up * Each pass through the following loop works its way up
* the rcu_node tree, returning if others have done the work or * the rcu_node tree, returning if others have done the work or
* otherwise falls through to acquire rsp->exp_mutex. The mapping * otherwise falls through to acquire ->exp_mutex. The mapping
* from CPU to rcu_node structure can be inexact, as it is just * from CPU to rcu_node structure can be inexact, as it is just
* promoting locality and is not strictly needed for correctness. * promoting locality and is not strictly needed for correctness.
*/ */
for (; rnp != NULL; rnp = rnp->parent) { for (; rnp != NULL; rnp = rnp->parent) {
if (sync_exp_work_done(rsp, s)) if (sync_exp_work_done(s))
return true; return true;
/* Work not done, either wait here or go up. */ /* Work not done, either wait here or go up. */
@ -314,26 +313,26 @@ static bool exp_funnel_lock(struct rcu_state *rsp, unsigned long s)
/* Someone else doing GP, so wait for them. */ /* Someone else doing GP, so wait for them. */
spin_unlock(&rnp->exp_lock); spin_unlock(&rnp->exp_lock);
trace_rcu_exp_funnel_lock(rsp->name, rnp->level, trace_rcu_exp_funnel_lock(rcu_state.name, rnp->level,
rnp->grplo, rnp->grphi, rnp->grplo, rnp->grphi,
TPS("wait")); TPS("wait"));
wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3], wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
sync_exp_work_done(rsp, s)); sync_exp_work_done(s));
return true; return true;
} }
rnp->exp_seq_rq = s; /* Followers can wait on us. */ rnp->exp_seq_rq = s; /* Followers can wait on us. */
spin_unlock(&rnp->exp_lock); spin_unlock(&rnp->exp_lock);
trace_rcu_exp_funnel_lock(rsp->name, rnp->level, rnp->grplo, trace_rcu_exp_funnel_lock(rcu_state.name, rnp->level,
rnp->grphi, TPS("nxtlvl")); rnp->grplo, rnp->grphi, TPS("nxtlvl"));
} }
mutex_lock(&rsp->exp_mutex); mutex_lock(&rcu_state.exp_mutex);
fastpath: fastpath:
if (sync_exp_work_done(rsp, s)) { if (sync_exp_work_done(s)) {
mutex_unlock(&rsp->exp_mutex); mutex_unlock(&rcu_state.exp_mutex);
return true; return true;
} }
rcu_exp_gp_seq_start(rsp); rcu_exp_gp_seq_start();
trace_rcu_exp_grace_period(rsp->name, s, TPS("start")); trace_rcu_exp_grace_period(rcu_state.name, s, TPS("start"));
return false; return false;
} }
@ -352,7 +351,6 @@ static void sync_rcu_exp_select_node_cpus(struct work_struct *wp)
struct rcu_exp_work *rewp = struct rcu_exp_work *rewp =
container_of(wp, struct rcu_exp_work, rew_work); container_of(wp, struct rcu_exp_work, rew_work);
struct rcu_node *rnp = container_of(rewp, struct rcu_node, rew); struct rcu_node *rnp = container_of(rewp, struct rcu_node, rew);
struct rcu_state *rsp = rewp->rew_rsp;
func = rewp->rew_func; func = rewp->rew_func;
raw_spin_lock_irqsave_rcu_node(rnp, flags); raw_spin_lock_irqsave_rcu_node(rnp, flags);
@ -400,7 +398,7 @@ retry_ipi:
mask_ofl_test |= mask; mask_ofl_test |= mask;
continue; continue;
} }
ret = smp_call_function_single(cpu, func, rsp, 0); ret = smp_call_function_single(cpu, func, NULL, 0);
if (!ret) { if (!ret) {
mask_ofl_ipi &= ~mask; mask_ofl_ipi &= ~mask;
continue; continue;
@ -411,7 +409,7 @@ retry_ipi:
(rnp->expmask & mask)) { (rnp->expmask & mask)) {
/* Online, so delay for a bit and try again. */ /* Online, so delay for a bit and try again. */
raw_spin_unlock_irqrestore_rcu_node(rnp, flags); raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("selectofl")); trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("selectofl"));
schedule_timeout_uninterruptible(1); schedule_timeout_uninterruptible(1);
goto retry_ipi; goto retry_ipi;
} }
@ -423,33 +421,31 @@ retry_ipi:
/* Report quiescent states for those that went offline. */ /* Report quiescent states for those that went offline. */
mask_ofl_test |= mask_ofl_ipi; mask_ofl_test |= mask_ofl_ipi;
if (mask_ofl_test) if (mask_ofl_test)
rcu_report_exp_cpu_mult(rsp, rnp, mask_ofl_test, false); rcu_report_exp_cpu_mult(rnp, mask_ofl_test, false);
} }
/* /*
* Select the nodes that the upcoming expedited grace period needs * Select the nodes that the upcoming expedited grace period needs
* to wait for. * to wait for.
*/ */
static void sync_rcu_exp_select_cpus(struct rcu_state *rsp, static void sync_rcu_exp_select_cpus(smp_call_func_t func)
smp_call_func_t func)
{ {
int cpu; int cpu;
struct rcu_node *rnp; struct rcu_node *rnp;
trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("reset")); trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("reset"));
sync_exp_reset_tree(rsp); sync_exp_reset_tree();
trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("select")); trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("select"));
/* Schedule work for each leaf rcu_node structure. */ /* Schedule work for each leaf rcu_node structure. */
rcu_for_each_leaf_node(rsp, rnp) { rcu_for_each_leaf_node(&rcu_state, rnp) {
rnp->exp_need_flush = false; rnp->exp_need_flush = false;
if (!READ_ONCE(rnp->expmask)) if (!READ_ONCE(rnp->expmask))
continue; /* Avoid early boot non-existent wq. */ continue; /* Avoid early boot non-existent wq. */
rnp->rew.rew_func = func; rnp->rew.rew_func = func;
rnp->rew.rew_rsp = rsp;
if (!READ_ONCE(rcu_par_gp_wq) || if (!READ_ONCE(rcu_par_gp_wq) ||
rcu_scheduler_active != RCU_SCHEDULER_RUNNING || rcu_scheduler_active != RCU_SCHEDULER_RUNNING ||
rcu_is_last_leaf_node(rsp, rnp)) { rcu_is_last_leaf_node(&rcu_state, rnp)) {
/* No workqueues yet or last leaf, do direct call. */ /* No workqueues yet or last leaf, do direct call. */
sync_rcu_exp_select_node_cpus(&rnp->rew.rew_work); sync_rcu_exp_select_node_cpus(&rnp->rew.rew_work);
continue; continue;
@ -466,12 +462,12 @@ static void sync_rcu_exp_select_cpus(struct rcu_state *rsp,
} }
/* Wait for workqueue jobs (if any) to complete. */ /* Wait for workqueue jobs (if any) to complete. */
rcu_for_each_leaf_node(rsp, rnp) rcu_for_each_leaf_node(&rcu_state, rnp)
if (rnp->exp_need_flush) if (rnp->exp_need_flush)
flush_work(&rnp->rew.rew_work); flush_work(&rnp->rew.rew_work);
} }
static void synchronize_sched_expedited_wait(struct rcu_state *rsp) static void synchronize_sched_expedited_wait(void)
{ {
int cpu; int cpu;
unsigned long jiffies_stall; unsigned long jiffies_stall;
@ -482,13 +478,13 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
struct rcu_node *rnp_root = rcu_get_root(); struct rcu_node *rnp_root = rcu_get_root();
int ret; int ret;
trace_rcu_exp_grace_period(rsp->name, rcu_exp_gp_seq_endval(rsp), TPS("startwait")); trace_rcu_exp_grace_period(rcu_state.name, rcu_exp_gp_seq_endval(), TPS("startwait"));
jiffies_stall = rcu_jiffies_till_stall_check(); jiffies_stall = rcu_jiffies_till_stall_check();
jiffies_start = jiffies; jiffies_start = jiffies;
for (;;) { for (;;) {
ret = swait_event_timeout_exclusive( ret = swait_event_timeout_exclusive(
rsp->expedited_wq, rcu_state.expedited_wq,
sync_rcu_preempt_exp_done_unlocked(rnp_root), sync_rcu_preempt_exp_done_unlocked(rnp_root),
jiffies_stall); jiffies_stall);
if (ret > 0 || sync_rcu_preempt_exp_done_unlocked(rnp_root)) if (ret > 0 || sync_rcu_preempt_exp_done_unlocked(rnp_root))
@ -498,9 +494,9 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
continue; continue;
panic_on_rcu_stall(); panic_on_rcu_stall();
pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {", pr_err("INFO: %s detected expedited stalls on CPUs/tasks: {",
rsp->name); rcu_state.name);
ndetected = 0; ndetected = 0;
rcu_for_each_leaf_node(rsp, rnp) { rcu_for_each_leaf_node(&rcu_state, rnp) {
ndetected += rcu_print_task_exp_stall(rnp); ndetected += rcu_print_task_exp_stall(rnp);
for_each_leaf_node_possible_cpu(rnp, cpu) { for_each_leaf_node_possible_cpu(rnp, cpu) {
struct rcu_data *rdp; struct rcu_data *rdp;
@ -517,11 +513,11 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
} }
} }
pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n", pr_cont(" } %lu jiffies s: %lu root: %#lx/%c\n",
jiffies - jiffies_start, rsp->expedited_sequence, jiffies - jiffies_start, rcu_state.expedited_sequence,
rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]); rnp_root->expmask, ".T"[!!rnp_root->exp_tasks]);
if (ndetected) { if (ndetected) {
pr_err("blocking rcu_node structures:"); pr_err("blocking rcu_node structures:");
rcu_for_each_node_breadth_first(rsp, rnp) { rcu_for_each_node_breadth_first(&rcu_state, rnp) {
if (rnp == rnp_root) if (rnp == rnp_root)
continue; /* printed unconditionally */ continue; /* printed unconditionally */
if (sync_rcu_preempt_exp_done_unlocked(rnp)) if (sync_rcu_preempt_exp_done_unlocked(rnp))
@ -533,7 +529,7 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
} }
pr_cont("\n"); pr_cont("\n");
} }
rcu_for_each_leaf_node(rsp, rnp) { rcu_for_each_leaf_node(&rcu_state, rnp) {
for_each_leaf_node_possible_cpu(rnp, cpu) { for_each_leaf_node_possible_cpu(rnp, cpu) {
mask = leaf_node_cpu_bit(rnp, cpu); mask = leaf_node_cpu_bit(rnp, cpu);
if (!(rnp->expmask & mask)) if (!(rnp->expmask & mask))
@ -551,21 +547,21 @@ static void synchronize_sched_expedited_wait(struct rcu_state *rsp)
* grace period. Also update all the ->exp_seq_rq counters as needed * grace period. Also update all the ->exp_seq_rq counters as needed
* in order to avoid counter-wrap problems. * in order to avoid counter-wrap problems.
*/ */
static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s) static void rcu_exp_wait_wake(unsigned long s)
{ {
struct rcu_node *rnp; struct rcu_node *rnp;
synchronize_sched_expedited_wait(rsp); synchronize_sched_expedited_wait();
rcu_exp_gp_seq_end(rsp); rcu_exp_gp_seq_end();
trace_rcu_exp_grace_period(rsp->name, s, TPS("end")); trace_rcu_exp_grace_period(rcu_state.name, s, TPS("end"));
/* /*
* Switch over to wakeup mode, allowing the next GP, but -only- the * Switch over to wakeup mode, allowing the next GP, but -only- the
* next GP, to proceed. * next GP, to proceed.
*/ */
mutex_lock(&rsp->exp_wake_mutex); mutex_lock(&rcu_state.exp_wake_mutex);
rcu_for_each_node_breadth_first(rsp, rnp) { rcu_for_each_node_breadth_first(&rcu_state, rnp) {
if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) { if (ULONG_CMP_LT(READ_ONCE(rnp->exp_seq_rq), s)) {
spin_lock(&rnp->exp_lock); spin_lock(&rnp->exp_lock);
/* Recheck, avoid hang in case someone just arrived. */ /* Recheck, avoid hang in case someone just arrived. */
@ -574,24 +570,23 @@ static void rcu_exp_wait_wake(struct rcu_state *rsp, unsigned long s)
spin_unlock(&rnp->exp_lock); spin_unlock(&rnp->exp_lock);
} }
smp_mb(); /* All above changes before wakeup. */ smp_mb(); /* All above changes before wakeup. */
wake_up_all(&rnp->exp_wq[rcu_seq_ctr(rsp->expedited_sequence) & 0x3]); wake_up_all(&rnp->exp_wq[rcu_seq_ctr(rcu_state.expedited_sequence) & 0x3]);
} }
trace_rcu_exp_grace_period(rsp->name, s, TPS("endwake")); trace_rcu_exp_grace_period(rcu_state.name, s, TPS("endwake"));
mutex_unlock(&rsp->exp_wake_mutex); mutex_unlock(&rcu_state.exp_wake_mutex);
} }
/* /*
* Common code to drive an expedited grace period forward, used by * Common code to drive an expedited grace period forward, used by
* workqueues and mid-boot-time tasks. * workqueues and mid-boot-time tasks.
*/ */
static void rcu_exp_sel_wait_wake(struct rcu_state *rsp, static void rcu_exp_sel_wait_wake(smp_call_func_t func, unsigned long s)
smp_call_func_t func, unsigned long s)
{ {
/* Initialize the rcu_node tree in preparation for the wait. */ /* Initialize the rcu_node tree in preparation for the wait. */
sync_rcu_exp_select_cpus(rsp, func); sync_rcu_exp_select_cpus(func);
/* Wait and clean up, including waking everyone. */ /* Wait and clean up, including waking everyone. */
rcu_exp_wait_wake(rsp, s); rcu_exp_wait_wake(s);
} }
/* /*
@ -602,15 +597,14 @@ static void wait_rcu_exp_gp(struct work_struct *wp)
struct rcu_exp_work *rewp; struct rcu_exp_work *rewp;
rewp = container_of(wp, struct rcu_exp_work, rew_work); rewp = container_of(wp, struct rcu_exp_work, rew_work);
rcu_exp_sel_wait_wake(rewp->rew_rsp, rewp->rew_func, rewp->rew_s); rcu_exp_sel_wait_wake(rewp->rew_func, rewp->rew_s);
} }
/* /*
* Given an rcu_state pointer and a smp_call_function() handler, kick * Given an rcu_state pointer and a smp_call_function() handler, kick
* off the specified flavor of expedited grace period. * off the specified flavor of expedited grace period.
*/ */
static void _synchronize_rcu_expedited(struct rcu_state *rsp, static void _synchronize_rcu_expedited(smp_call_func_t func)
smp_call_func_t func)
{ {
struct rcu_data *rdp; struct rcu_data *rdp;
struct rcu_exp_work rew; struct rcu_exp_work rew;
@ -624,18 +618,17 @@ static void _synchronize_rcu_expedited(struct rcu_state *rsp,
} }
/* Take a snapshot of the sequence number. */ /* Take a snapshot of the sequence number. */
s = rcu_exp_gp_seq_snap(rsp); s = rcu_exp_gp_seq_snap();
if (exp_funnel_lock(rsp, s)) if (exp_funnel_lock(s))
return; /* Someone else did our work for us. */ return; /* Someone else did our work for us. */
/* Ensure that load happens before action based on it. */ /* Ensure that load happens before action based on it. */
if (unlikely(rcu_scheduler_active == RCU_SCHEDULER_INIT)) { if (unlikely(rcu_scheduler_active == RCU_SCHEDULER_INIT)) {
/* Direct call during scheduler init and early_initcalls(). */ /* Direct call during scheduler init and early_initcalls(). */
rcu_exp_sel_wait_wake(rsp, func, s); rcu_exp_sel_wait_wake(func, s);
} else { } else {
/* Marshall arguments & schedule the expedited grace period. */ /* Marshall arguments & schedule the expedited grace period. */
rew.rew_func = func; rew.rew_func = func;
rew.rew_rsp = rsp;
rew.rew_s = s; rew.rew_s = s;
INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp); INIT_WORK_ONSTACK(&rew.rew_work, wait_rcu_exp_gp);
queue_work(rcu_gp_wq, &rew.rew_work); queue_work(rcu_gp_wq, &rew.rew_work);
@ -645,11 +638,11 @@ static void _synchronize_rcu_expedited(struct rcu_state *rsp,
rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id()); rdp = per_cpu_ptr(&rcu_data, raw_smp_processor_id());
rnp = rcu_get_root(); rnp = rcu_get_root();
wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3], wait_event(rnp->exp_wq[rcu_seq_ctr(s) & 0x3],
sync_exp_work_done(rsp, s)); sync_exp_work_done(s));
smp_mb(); /* Workqueue actions happen before return. */ smp_mb(); /* Workqueue actions happen before return. */
/* Let the next expedited grace period start. */ /* Let the next expedited grace period start. */
mutex_unlock(&rsp->exp_mutex); mutex_unlock(&rcu_state.exp_mutex);
} }
#ifdef CONFIG_PREEMPT_RCU #ifdef CONFIG_PREEMPT_RCU
@ -661,10 +654,9 @@ static void _synchronize_rcu_expedited(struct rcu_state *rsp,
* ->expmask fields in the rcu_node tree. Otherwise, immediately * ->expmask fields in the rcu_node tree. Otherwise, immediately
* report the quiescent state. * report the quiescent state.
*/ */
static void sync_rcu_exp_handler(void *info) static void sync_rcu_exp_handler(void *unused)
{ {
unsigned long flags; unsigned long flags;
struct rcu_state *rsp = info;
struct rcu_data *rdp = this_cpu_ptr(&rcu_data); struct rcu_data *rdp = this_cpu_ptr(&rcu_data);
struct rcu_node *rnp = rdp->mynode; struct rcu_node *rnp = rdp->mynode;
struct task_struct *t = current; struct task_struct *t = current;
@ -677,7 +669,7 @@ static void sync_rcu_exp_handler(void *info)
if (!t->rcu_read_lock_nesting) { if (!t->rcu_read_lock_nesting) {
if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) || if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||
rcu_dynticks_curr_cpu_in_eqs()) { rcu_dynticks_curr_cpu_in_eqs()) {
rcu_report_exp_rdp(rsp, rdp); rcu_report_exp_rdp(rdp);
} else { } else {
rdp->deferred_qs = true; rdp->deferred_qs = true;
resched_cpu(rdp->cpu); resched_cpu(rdp->cpu);
@ -756,8 +748,6 @@ static void sync_sched_exp_online_cleanup(int cpu)
*/ */
void synchronize_rcu_expedited(void) void synchronize_rcu_expedited(void)
{ {
struct rcu_state *rsp = &rcu_state;
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) || RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_lock_map) ||
lock_is_held(&rcu_sched_lock_map), lock_is_held(&rcu_sched_lock_map),
@ -765,7 +755,7 @@ void synchronize_rcu_expedited(void)
if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE) if (rcu_scheduler_active == RCU_SCHEDULER_INACTIVE)
return; return;
_synchronize_rcu_expedited(rsp, sync_rcu_exp_handler); _synchronize_rcu_expedited(sync_rcu_exp_handler);
} }
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);
@ -783,7 +773,7 @@ static void sync_sched_exp_handler(void *unused)
__this_cpu_read(rcu_data.cpu_no_qs.b.exp)) __this_cpu_read(rcu_data.cpu_no_qs.b.exp))
return; return;
if (rcu_is_cpu_rrupt_from_idle()) { if (rcu_is_cpu_rrupt_from_idle()) {
rcu_report_exp_rdp(&rcu_state, this_cpu_ptr(&rcu_data)); rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
return; return;
} }
__this_cpu_write(rcu_data.cpu_no_qs.b.exp, true); __this_cpu_write(rcu_data.cpu_no_qs.b.exp, true);
@ -798,13 +788,12 @@ static void sync_sched_exp_online_cleanup(int cpu)
struct rcu_data *rdp; struct rcu_data *rdp;
int ret; int ret;
struct rcu_node *rnp; struct rcu_node *rnp;
struct rcu_state *rsp = &rcu_state;
rdp = per_cpu_ptr(&rcu_data, cpu); rdp = per_cpu_ptr(&rcu_data, cpu);
rnp = rdp->mynode; rnp = rdp->mynode;
if (!(READ_ONCE(rnp->expmask) & rdp->grpmask)) if (!(READ_ONCE(rnp->expmask) & rdp->grpmask))
return; return;
ret = smp_call_function_single(cpu, sync_sched_exp_handler, rsp, 0); ret = smp_call_function_single(cpu, sync_sched_exp_handler, NULL, 0);
WARN_ON_ONCE(ret); WARN_ON_ONCE(ret);
} }
@ -831,8 +820,6 @@ static int rcu_blocking_is_gp(void)
/* PREEMPT=n implementation of synchronize_rcu_expedited(). */ /* PREEMPT=n implementation of synchronize_rcu_expedited(). */
void synchronize_rcu_expedited(void) void synchronize_rcu_expedited(void)
{ {
struct rcu_state *rsp = &rcu_state;
RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) || RCU_LOCKDEP_WARN(lock_is_held(&rcu_bh_lock_map) ||
lock_is_held(&rcu_lock_map) || lock_is_held(&rcu_lock_map) ||
lock_is_held(&rcu_sched_lock_map), lock_is_held(&rcu_sched_lock_map),
@ -842,7 +829,7 @@ void synchronize_rcu_expedited(void)
if (rcu_blocking_is_gp()) if (rcu_blocking_is_gp())
return; return;
_synchronize_rcu_expedited(rsp, sync_sched_exp_handler); _synchronize_rcu_expedited(sync_sched_exp_handler);
} }
EXPORT_SYMBOL_GPL(synchronize_rcu_expedited); EXPORT_SYMBOL_GPL(synchronize_rcu_expedited);

13
kernel/rcu/tree_plugin.h
Просмотреть файл

@ -123,8 +123,7 @@ static void __init rcu_bootup_announce_oddness(void)
#ifdef CONFIG_PREEMPT_RCU #ifdef CONFIG_PREEMPT_RCU
static void rcu_report_exp_rnp(struct rcu_state *rsp, struct rcu_node *rnp, static void rcu_report_exp_rnp(struct rcu_node *rnp, bool wake);
bool wake);
static void rcu_read_unlock_special(struct task_struct *t); static void rcu_read_unlock_special(struct task_struct *t);
/* /*
@ -281,7 +280,7 @@ static void rcu_preempt_ctxt_queue(struct rcu_node *rnp, struct rcu_data *rdp)
* still in a quiescent state in any case.) * still in a quiescent state in any case.)
*/ */
if (blkd_state & RCU_EXP_BLKD && rdp->deferred_qs) if (blkd_state & RCU_EXP_BLKD && rdp->deferred_qs)
rcu_report_exp_rdp(rdp->rsp, rdp); rcu_report_exp_rdp(rdp);
else else
WARN_ON_ONCE(rdp->deferred_qs); WARN_ON_ONCE(rdp->deferred_qs);
} }
@ -381,7 +380,7 @@ void rcu_note_context_switch(bool preempt)
*/ */
rcu_qs(); rcu_qs();
if (rdp->deferred_qs) if (rdp->deferred_qs)
rcu_report_exp_rdp(&rcu_state, rdp); rcu_report_exp_rdp(rdp);
trace_rcu_utilization(TPS("End context switch")); trace_rcu_utilization(TPS("End context switch"));
barrier(); /* Avoid RCU read-side critical sections leaking up. */ barrier(); /* Avoid RCU read-side critical sections leaking up. */
} }
@ -509,7 +508,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
* blocked-tasks list below. * blocked-tasks list below.
*/ */
if (rdp->deferred_qs) { if (rdp->deferred_qs) {
rcu_report_exp_rdp(&rcu_state, rdp); rcu_report_exp_rdp(rdp);
if (!t->rcu_read_unlock_special.s) { if (!t->rcu_read_unlock_special.s) {
local_irq_restore(flags); local_irq_restore(flags);
return; return;
@ -580,7 +579,7 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
* then we need to report up the rcu_node hierarchy. * then we need to report up the rcu_node hierarchy.
*/ */
if (!empty_exp && empty_exp_now) if (!empty_exp && empty_exp_now)
rcu_report_exp_rnp(&rcu_state, rnp, true); rcu_report_exp_rnp(rnp, true);
} else { } else {
local_irq_restore(flags); local_irq_restore(flags);
} }
@ -947,7 +946,7 @@ static void rcu_qs(void)
if (!__this_cpu_read(rcu_data.cpu_no_qs.b.exp)) if (!__this_cpu_read(rcu_data.cpu_no_qs.b.exp))
return; return;
__this_cpu_write(rcu_data.cpu_no_qs.b.exp, false); __this_cpu_write(rcu_data.cpu_no_qs.b.exp, false);
rcu_report_exp_rdp(&rcu_state, this_cpu_ptr(&rcu_data)); rcu_report_exp_rdp(this_cpu_ptr(&rcu_data));
} }
/* /*