Commit 35dc0352 authored by Linus Torvalds's avatar Linus Torvalds

Merge tag 'rcu.2022.03.13a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu

Pull RCU updates from Paul McKenney:

 - Fix idle detection (Neeraj Upadhyay) and missing access marking
   detected by KCSAN.

 - Reduce coupling between rcu_barrier() and CPU-hotplug operations, so
   that rcu_barrier() no longer needs to do cpus_read_lock(). This may
   also someday allow system boot to bring CPUs online concurrently.

 - Enable more aggressive movement to per-CPU queueing when reacting to
   excessive lock contention due to workloads placing heavy update-side
   stress on RCU tasks.

 - Improvements to RCU priority boosting, including changes from Neeraj
   Upadhyay, Zqiang, and Alison Chaiken.

 - Various fixes improving test robustness and debug information.

 - Add tests for SRCU size transitions, further compress torture.sh
   build products, and improve debug output.

 - Miscellaneous fixes.

* tag 'rcu.2022.03.13a' of git://git.kernel.org/pub/scm/linux/kernel/git/paulmck/linux-rcu: (49 commits)
  rcu: Replace cpumask_weight with cpumask_empty where appropriate
  rcu: Remove __read_mostly annotations from rcu_scheduler_active externs
  rcu: Uninline multi-use function: finish_rcuwait()
  rcu: Mark writes to the rcu_segcblist structure's ->flags field
  kasan: Record work creation stack trace with interrupts enabled
  rcu: Inline __call_rcu() into call_rcu()
  rcu: Add mutex for rcu boost kthread spawning and affinity setting
  rcu: Fix description of kvfree_rcu()
  MAINTAINERS:  Add Frederic and Neeraj to their RCU files
  rcutorture: Provide non-power-of-two Tasks RCU scenarios
  rcutorture: Test SRCU size transitions
  torture: Make torture.sh help message match reality
  rcu-tasks: Set ->percpu_enqueue_shift to zero upon contention
  rcu-tasks: Use order_base_2() instead of ilog2()
  rcu: Create and use an rcu_rdp_cpu_online()
  rcu: Make rcu_barrier() no longer block CPU-hotplug operations
  rcu: Rework rcu_barrier() and callback-migration logic
  rcu: Refactor rcu_barrier() empty-list handling
  rcu: Kill rnp->ofl_seq and use only rcu_state.ofl_lock for exclusion
  torture: Change KVM environment variable to RCUTORTURE
  ...
parents a04b1bf5 d5578190
......@@ -4504,6 +4504,8 @@
(the least-favored priority). Otherwise, when
RCU_BOOST is not set, valid values are 0-99 and
the default is zero (non-realtime operation).
When RCU_NOCB_CPU is set, also adjust the
priority of NOCB callback kthreads.
rcutree.rcu_nocb_gp_stride= [KNL]
Set the number of NOCB callback kthreads in
......
......@@ -16324,6 +16324,8 @@ F: tools/testing/selftests/resctrl/
READ-COPY UPDATE (RCU)
M: "Paul E. McKenney" <paulmck@kernel.org>
M: Frederic Weisbecker <frederic@kernel.org> (kernel/rcu/tree_nocb.h)
M: Neeraj Upadhyay <quic_neeraju@quicinc.com> (kernel/rcu/tasks.h)
M: Josh Triplett <josh@joshtriplett.org>
R: Steven Rostedt <rostedt@goodmis.org>
R: Mathieu Desnoyers <mathieu.desnoyers@efficios.com>
......
......@@ -84,7 +84,7 @@ static inline int rcu_preempt_depth(void)
/* Internal to kernel */
void rcu_init(void);
extern int rcu_scheduler_active __read_mostly;
extern int rcu_scheduler_active;
void rcu_sched_clock_irq(int user);
void rcu_report_dead(unsigned int cpu);
void rcutree_migrate_callbacks(int cpu);
......@@ -924,7 +924,7 @@ static inline notrace void rcu_read_unlock_sched_notrace(void)
*
* kvfree_rcu(ptr);
*
* where @ptr is a pointer to kvfree().
* where @ptr is the pointer to be freed by kvfree().
*
* Please note, head-less way of freeing is permitted to
* use from a context that has to follow might_sleep()
......
......@@ -62,7 +62,7 @@ static inline void rcu_irq_exit_check_preempt(void) { }
void exit_rcu(void);
void rcu_scheduler_starting(void);
extern int rcu_scheduler_active __read_mostly;
extern int rcu_scheduler_active;
void rcu_end_inkernel_boot(void);
bool rcu_inkernel_boot_has_ended(void);
bool rcu_is_watching(void);
......
......@@ -47,11 +47,7 @@ static inline void prepare_to_rcuwait(struct rcuwait *w)
rcu_assign_pointer(w->task, current);
}
static inline void finish_rcuwait(struct rcuwait *w)
{
rcu_assign_pointer(w->task, NULL);
__set_current_state(TASK_RUNNING);
}
extern void finish_rcuwait(struct rcuwait *w);
#define rcuwait_wait_event(w, condition, state) \
({ \
......
......@@ -794,16 +794,15 @@ TRACE_EVENT_RCU(rcu_torture_read,
* Tracepoint for rcu_barrier() execution. The string "s" describes
* the rcu_barrier phase:
* "Begin": rcu_barrier() started.
* "CB": An rcu_barrier_callback() invoked a callback, not the last.
* "EarlyExit": rcu_barrier() piggybacked, thus early exit.
* "Inc1": rcu_barrier() piggyback check counter incremented.
* "OfflineNoCBQ": rcu_barrier() found offline no-CBs CPU with callbacks.
* "OnlineQ": rcu_barrier() found online CPU with callbacks.
* "OnlineNQ": rcu_barrier() found online CPU, no callbacks.
* "Inc2": rcu_barrier() piggyback check counter incremented.
* "IRQ": An rcu_barrier_callback() callback posted on remote CPU.
* "IRQNQ": An rcu_barrier_callback() callback found no callbacks.
* "CB": An rcu_barrier_callback() invoked a callback, not the last.
* "LastCB": An rcu_barrier_callback() invoked the last callback.
* "Inc2": rcu_barrier() piggyback check counter incremented.
* "NQ": rcu_barrier() found a CPU with no callbacks.
* "OnlineQ": rcu_barrier() found online CPU with callbacks.
* The "cpu" argument is the CPU or -1 if meaningless, the "cnt" argument
* is the count of remaining callbacks, and "done" is the piggybacking count.
*/
......
......@@ -56,13 +56,13 @@ static inline long rcu_segcblist_n_cbs(struct rcu_segcblist *rsclp)
static inline void rcu_segcblist_set_flags(struct rcu_segcblist *rsclp,
int flags)
{
rsclp->flags |= flags;
WRITE_ONCE(rsclp->flags, rsclp->flags | flags);
}
static inline void rcu_segcblist_clear_flags(struct rcu_segcblist *rsclp,
int flags)
{
rsclp->flags &= ~flags;
WRITE_ONCE(rsclp->flags, rsclp->flags & ~flags);
}
static inline bool rcu_segcblist_test_flags(struct rcu_segcblist *rsclp,
......
......@@ -284,7 +284,7 @@ static atomic_t barrier_cbs_invoked; /* Barrier callbacks invoked. */
static wait_queue_head_t *barrier_cbs_wq; /* Coordinate barrier testing. */
static DECLARE_WAIT_QUEUE_HEAD(barrier_wq);
static bool rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
static atomic_t rcu_fwd_cb_nodelay; /* Short rcu_torture_delay() delays. */
/*
* Allocate an element from the rcu_tortures pool.
......@@ -387,7 +387,7 @@ rcu_read_delay(struct torture_random_state *rrsp, struct rt_read_seg *rtrsp)
* period, and we want a long delay occasionally to trigger
* force_quiescent_state. */
if (!READ_ONCE(rcu_fwd_cb_nodelay) &&
if (!atomic_read(&rcu_fwd_cb_nodelay) &&
!(torture_random(rrsp) % (nrealreaders * 2000 * longdelay_ms))) {
started = cur_ops->get_gp_seq();
ts = rcu_trace_clock_local();
......@@ -674,6 +674,7 @@ static struct rcu_torture_ops srcu_ops = {
.call = srcu_torture_call,
.cb_barrier = srcu_torture_barrier,
.stats = srcu_torture_stats,
.cbflood_max = 50000,
.irq_capable = 1,
.no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
.name = "srcu"
......@@ -708,6 +709,7 @@ static struct rcu_torture_ops srcud_ops = {
.call = srcu_torture_call,
.cb_barrier = srcu_torture_barrier,
.stats = srcu_torture_stats,
.cbflood_max = 50000,
.irq_capable = 1,
.no_pi_lock = IS_ENABLED(CONFIG_TINY_SRCU),
.name = "srcud"
......@@ -997,7 +999,7 @@ static int rcu_torture_boost(void *arg)
goto checkwait;
/* Wait for the next test interval. */
oldstarttime = boost_starttime;
oldstarttime = READ_ONCE(boost_starttime);
while (time_before(jiffies, oldstarttime)) {
schedule_timeout_interruptible(oldstarttime - jiffies);
if (stutter_wait("rcu_torture_boost"))
......@@ -1041,10 +1043,11 @@ static int rcu_torture_boost(void *arg)
* interval. Besides, we are running at RT priority,
* so delays should be relatively rare.
*/
while (oldstarttime == boost_starttime && !kthread_should_stop()) {
while (oldstarttime == READ_ONCE(boost_starttime) && !kthread_should_stop()) {
if (mutex_trylock(&boost_mutex)) {
if (oldstarttime == boost_starttime) {
boost_starttime = jiffies + test_boost_interval * HZ;
WRITE_ONCE(boost_starttime,
jiffies + test_boost_interval * HZ);
n_rcu_torture_boosts++;
}
mutex_unlock(&boost_mutex);
......@@ -1276,7 +1279,7 @@ rcu_torture_writer(void *arg)
boot_ended = rcu_inkernel_boot_has_ended();
stutter_waited = stutter_wait("rcu_torture_writer");
if (stutter_waited &&
!READ_ONCE(rcu_fwd_cb_nodelay) &&
!atomic_read(&rcu_fwd_cb_nodelay) &&
!cur_ops->slow_gps &&
!torture_must_stop() &&
boot_ended)
......@@ -2180,7 +2183,6 @@ static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
for (i = ARRAY_SIZE(rfp->n_launders_hist) - 1; i > 0; i--)
if (rfp->n_launders_hist[i].n_launders > 0)
break;
mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
pr_alert("%s: Callback-invocation histogram %d (duration %lu jiffies):",
__func__, rfp->rcu_fwd_id, jiffies - rfp->rcu_fwd_startat);
gps_old = rfp->rcu_launder_gp_seq_start;
......@@ -2193,7 +2195,6 @@ static void rcu_torture_fwd_cb_hist(struct rcu_fwd *rfp)
gps_old = gps;
}
pr_cont("\n");
mutex_unlock(&rcu_fwd_mutex);
}
/* Callback function for continuous-flood RCU callbacks. */
......@@ -2281,6 +2282,7 @@ static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
unsigned long stopat;
static DEFINE_TORTURE_RANDOM(trs);
pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
if (!cur_ops->sync)
return; // Cannot do need_resched() forward progress testing without ->sync.
if (cur_ops->call && cur_ops->cb_barrier) {
......@@ -2289,7 +2291,7 @@ static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
}
/* Tight loop containing cond_resched(). */
WRITE_ONCE(rcu_fwd_cb_nodelay, true);
atomic_inc(&rcu_fwd_cb_nodelay);
cur_ops->sync(); /* Later readers see above write. */
if (selfpropcb) {
WRITE_ONCE(fcs.stop, 0);
......@@ -2325,6 +2327,7 @@ static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
if (selfpropcb) {
WRITE_ONCE(fcs.stop, 1);
cur_ops->sync(); /* Wait for running CB to complete. */
pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
cur_ops->cb_barrier(); /* Wait for queued callbacks. */
}
......@@ -2333,7 +2336,7 @@ static void rcu_torture_fwd_prog_nr(struct rcu_fwd *rfp,
destroy_rcu_head_on_stack(&fcs.rh);
}
schedule_timeout_uninterruptible(HZ / 10); /* Let kthreads recover. */
WRITE_ONCE(rcu_fwd_cb_nodelay, false);
atomic_dec(&rcu_fwd_cb_nodelay);
}
/* Carry out call_rcu() forward-progress testing. */
......@@ -2353,13 +2356,14 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
unsigned long stopat;
unsigned long stoppedat;
pr_alert("%s: Starting forward-progress test %d\n", __func__, rfp->rcu_fwd_id);
if (READ_ONCE(rcu_fwd_emergency_stop))
return; /* Get out of the way quickly, no GP wait! */
if (!cur_ops->call)
return; /* Can't do call_rcu() fwd prog without ->call. */
/* Loop continuously posting RCU callbacks. */
WRITE_ONCE(rcu_fwd_cb_nodelay, true);
atomic_inc(&rcu_fwd_cb_nodelay);
cur_ops->sync(); /* Later readers see above write. */
WRITE_ONCE(rfp->rcu_fwd_startat, jiffies);
stopat = rfp->rcu_fwd_startat + MAX_FWD_CB_JIFFIES;
......@@ -2414,6 +2418,7 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
n_launders_cb_snap = READ_ONCE(rfp->n_launders_cb);
cver = READ_ONCE(rcu_torture_current_version) - cver;
gps = rcutorture_seq_diff(cur_ops->get_gp_seq(), gps);
pr_alert("%s: Waiting for CBs: %pS() %d\n", __func__, cur_ops->cb_barrier, rfp->rcu_fwd_id);
cur_ops->cb_barrier(); /* Wait for callbacks to be invoked. */
(void)rcu_torture_fwd_prog_cbfree(rfp);
......@@ -2427,11 +2432,13 @@ static void rcu_torture_fwd_prog_cr(struct rcu_fwd *rfp)
n_launders, n_launders_sa,
n_max_gps, n_max_cbs, cver, gps);
atomic_long_add(n_max_cbs, &rcu_fwd_max_cbs);
mutex_lock(&rcu_fwd_mutex); // Serialize histograms.
rcu_torture_fwd_cb_hist(rfp);
mutex_unlock(&rcu_fwd_mutex);
}
schedule_timeout_uninterruptible(HZ); /* Let CBs drain. */
tick_dep_clear_task(current, TICK_DEP_BIT_RCU);
WRITE_ONCE(rcu_fwd_cb_nodelay, false);
atomic_dec(&rcu_fwd_cb_nodelay);
}
......@@ -2511,7 +2518,7 @@ static int rcu_torture_fwd_prog(void *args)
firsttime = false;
WRITE_ONCE(rcu_fwd_seq, rcu_fwd_seq + 1);
} else {
while (READ_ONCE(rcu_fwd_seq) == oldseq)
while (READ_ONCE(rcu_fwd_seq) == oldseq && !torture_must_stop())
schedule_timeout_interruptible(1);
oldseq = READ_ONCE(rcu_fwd_seq);
}
......@@ -2905,8 +2912,10 @@ rcu_torture_cleanup(void)
int i;
if (torture_cleanup_begin()) {
if (cur_ops->cb_barrier != NULL)
if (cur_ops->cb_barrier != NULL) {
pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
cur_ops->cb_barrier();
}
return;
}
if (!cur_ops) {
......@@ -2961,8 +2970,10 @@ rcu_torture_cleanup(void)
* Wait for all RCU callbacks to fire, then do torture-type-specific
* cleanup operations.
*/
if (cur_ops->cb_barrier != NULL)
if (cur_ops->cb_barrier != NULL) {
pr_info("%s: Invoking %pS().\n", __func__, cur_ops->cb_barrier);
cur_ops->cb_barrier();
}
if (cur_ops->cleanup != NULL)
cur_ops->cleanup();
......
......@@ -123,7 +123,7 @@ static struct rcu_tasks rt_name = \
.call_func = call, \
.rtpcpu = &rt_name ## __percpu, \
.name = n, \
.percpu_enqueue_shift = ilog2(CONFIG_NR_CPUS) + 1, \
.percpu_enqueue_shift = order_base_2(CONFIG_NR_CPUS), \
.percpu_enqueue_lim = 1, \
.percpu_dequeue_lim = 1, \
.barrier_q_mutex = __MUTEX_INITIALIZER(rt_name.barrier_q_mutex), \
......@@ -302,7 +302,7 @@ static void call_rcu_tasks_generic(struct rcu_head *rhp, rcu_callback_t func,
if (unlikely(needadjust)) {
raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
if (rtp->percpu_enqueue_lim != nr_cpu_ids) {
WRITE_ONCE(rtp->percpu_enqueue_shift, ilog2(nr_cpu_ids) + 1);
WRITE_ONCE(rtp->percpu_enqueue_shift, 0);
WRITE_ONCE(rtp->percpu_dequeue_lim, nr_cpu_ids);
smp_store_release(&rtp->percpu_enqueue_lim, nr_cpu_ids);
pr_info("Switching %s to per-CPU callback queuing.\n", rtp->name);
......@@ -417,7 +417,7 @@ static int rcu_tasks_need_gpcb(struct rcu_tasks *rtp)
if (rcu_task_cb_adjust && ncbs <= rcu_task_collapse_lim) {
raw_spin_lock_irqsave(&rtp->cbs_gbl_lock, flags);
if (rtp->percpu_enqueue_lim > 1) {
WRITE_ONCE(rtp->percpu_enqueue_shift, ilog2(nr_cpu_ids) + 1);
WRITE_ONCE(rtp->percpu_enqueue_shift, order_base_2(nr_cpu_ids));
smp_store_release(&rtp->percpu_enqueue_lim, 1);
rtp->percpu_dequeue_gpseq = get_state_synchronize_rcu();
pr_info("Starting switch %s to CPU-0 callback queuing.\n", rtp->name);
......
This diff is collapsed.
......@@ -56,8 +56,6 @@ struct rcu_node {
/* Initialized from ->qsmaskinitnext at the */
/* beginning of each grace period. */
unsigned long qsmaskinitnext;
unsigned long ofl_seq; /* CPU-hotplug operation sequence count. */
/* Online CPUs for next grace period. */
unsigned long expmask; /* CPUs or groups that need to check in */
/* to allow the current expedited GP */
/* to complete. */
......@@ -110,6 +108,9 @@ struct rcu_node {
/* side effect, not as a lock. */
unsigned long boost_time;
/* When to start boosting (jiffies). */
struct mutex boost_kthread_mutex;
/* Exclusion for thread spawning and affinity */
/* manipulation. */
struct task_struct *boost_kthread_task;
/* kthread that takes care of priority */
/* boosting for this rcu_node structure. */
......@@ -190,6 +191,7 @@ struct rcu_data {
bool rcu_forced_tick_exp; /* ... provide QS to expedited GP. */
/* 4) rcu_barrier(), OOM callbacks, and expediting. */
unsigned long barrier_seq_snap; /* Snap of rcu_state.barrier_sequence. */
struct rcu_head barrier_head;
int exp_dynticks_snap; /* Double-check need for IPI. */
......@@ -203,6 +205,8 @@ struct rcu_data {
int nocb_defer_wakeup; /* Defer wakeup of nocb_kthread. */
struct timer_list nocb_timer; /* Enforce finite deferral. */
unsigned long nocb_gp_adv_time; /* Last call_rcu() CB adv (jiffies). */
struct mutex nocb_gp_kthread_mutex; /* Exclusion for nocb gp kthread */
/* spawning */
/* The following fields are used by call_rcu, hence own cacheline. */
raw_spinlock_t nocb_bypass_lock ____cacheline_internodealigned_in_smp;
......@@ -237,6 +241,7 @@ struct rcu_data {
/* rcuc per-CPU kthread or NULL. */
unsigned int rcu_cpu_kthread_status;
char rcu_cpu_has_work;
unsigned long rcuc_activity;
/* 7) Diagnostic data, including RCU CPU stall warnings. */
unsigned int softirq_snap; /* Snapshot of softirq activity. */
......@@ -302,9 +307,8 @@ struct rcu_state {
/* The following fields are guarded by the root rcu_node's lock. */
u8 boost ____cacheline_internodealigned_in_smp;
/* Subject to priority boost. */
unsigned long gp_seq; /* Grace-period sequence #. */
unsigned long gp_seq ____cacheline_internodealigned_in_smp;
/* Grace-period sequence #. */
unsigned long gp_max; /* Maximum GP duration in */
/* jiffies. */
struct task_struct *gp_kthread; /* Task for grace periods. */
......@@ -323,6 +327,8 @@ struct rcu_state {
/* rcu_barrier(). */
/* End of fields guarded by barrier_mutex. */
raw_spinlock_t barrier_lock; /* Protects ->barrier_seq_snap. */
struct mutex exp_mutex; /* Serialize expedited GP. */
struct mutex exp_wake_mutex; /* Serialize wakeup. */
unsigned long expedited_sequence; /* Take a ticket. */
......@@ -355,7 +361,7 @@ struct rcu_state {
const char *name; /* Name of structure. */
char abbr; /* Abbreviated name. */
raw_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
arch_spinlock_t ofl_lock ____cacheline_internodealigned_in_smp;
/* Synchronize offline with */
/* GP pre-initialization. */
};
......
......@@ -502,7 +502,8 @@ static void synchronize_rcu_expedited_wait(void)
if (synchronize_rcu_expedited_wait_once(1))
return;
rcu_for_each_leaf_node(rnp) {
for_each_leaf_node_cpu_mask(rnp, cpu, rnp->expmask) {
mask = READ_ONCE(rnp->expmask);
for_each_leaf_node_cpu_mask(rnp, cpu, mask) {
rdp = per_cpu_ptr(&rcu_data, cpu);
if (rdp->rcu_forced_tick_exp)
continue;
......@@ -656,7 +657,7 @@ static void rcu_exp_handler(void *unused)
*/
if (!depth) {
if (!(preempt_count() & (PREEMPT_MASK | SOFTIRQ_MASK)) ||
rcu_dynticks_curr_cpu_in_eqs()) {
rcu_is_cpu_rrupt_from_idle()) {
rcu_report_exp_rdp(rdp);
} else {
WRITE_ONCE(rdp->cpu_no_qs.b.exp, true);
......
......@@ -1169,7 +1169,7 @@ void __init rcu_init_nohz(void)
struct rcu_data *rdp;
#if defined(CONFIG_NO_HZ_FULL)
if (tick_nohz_full_running && cpumask_weight(tick_nohz_full_mask))
if (tick_nohz_full_running && !cpumask_empty(tick_nohz_full_mask))
need_rcu_nocb_mask = true;
#endif /* #if defined(CONFIG_NO_HZ_FULL) */
......@@ -1226,6 +1226,7 @@ static void __init rcu_boot_init_nocb_percpu_data(struct rcu_data *rdp)
raw_spin_lock_init(&rdp->nocb_gp_lock);
timer_setup(&rdp->nocb_timer, do_nocb_deferred_wakeup_timer, 0);
rcu_cblist_init(&rdp->nocb_bypass);
mutex_init(&rdp->nocb_gp_kthread_mutex);
}
/*
......@@ -1238,6 +1239,7 @@ static void rcu_spawn_cpu_nocb_kthread(int cpu)
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
struct rcu_data *rdp_gp;
struct task_struct *t;
struct sched_param sp;
if (!rcu_scheduler_fully_active || !rcu_nocb_is_setup)
return;
......@@ -1247,20 +1249,30 @@ static void rcu_spawn_cpu_nocb_kthread(int cpu)
return;
/* If we didn't spawn the GP kthread first, reorganize! */
sp.sched_priority = kthread_prio;
rdp_gp = rdp->nocb_gp_rdp;
mutex_lock(&rdp_gp->nocb_gp_kthread_mutex);
if (!rdp_gp->nocb_gp_kthread) {
t = kthread_run(rcu_nocb_gp_kthread, rdp_gp,
"rcuog/%d", rdp_gp->cpu);
if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo GP kthread, OOM is now expected behavior\n", __func__))
if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo GP kthread, OOM is now expected behavior\n", __func__)) {
mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
return;
}
WRITE_ONCE(rdp_gp->nocb_gp_kthread, t);
if (kthread_prio)
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
}
mutex_unlock(&rdp_gp->nocb_gp_kthread_mutex);
/* Spawn the kthread for this CPU. */
t = kthread_run(rcu_nocb_cb_kthread, rdp,
"rcuo%c/%d", rcu_state.abbr, cpu);
if (WARN_ONCE(IS_ERR(t), "%s: Could not start rcuo CB kthread, OOM is now expected behavior\n", __func__))
return;
if (kthread_prio)
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
WRITE_ONCE(rdp->nocb_cb_kthread, t);
WRITE_ONCE(rdp->nocb_gp_kthread, rdp_gp->nocb_gp_kthread);
}
......@@ -1348,7 +1360,7 @@ static void __init rcu_organize_nocb_kthreads(void)
*/
void rcu_bind_current_to_nocb(void)
{
if (cpumask_available(rcu_nocb_mask) && cpumask_weight(rcu_nocb_mask))
if (cpumask_available(rcu_nocb_mask) && !cpumask_empty(rcu_nocb_mask))
WARN_ON(sched_setaffinity(current->pid, rcu_nocb_mask));
}
EXPORT_SYMBOL_GPL(rcu_bind_current_to_nocb);
......
......@@ -330,7 +330,7 @@ void rcu_note_context_switch(bool preempt)
* then queue the task as required based on the states
* of any ongoing and expedited grace periods.
*/
WARN_ON_ONCE((rdp->grpmask & rcu_rnp_online_cpus(rnp)) == 0);
WARN_ON_ONCE(!rcu_rdp_cpu_online(rdp));
WARN_ON_ONCE(!list_empty(&t->rcu_node_entry));
trace_rcu_preempt_task(rcu_state.name,
t->pid,
......@@ -556,16 +556,16 @@ rcu_preempt_deferred_qs_irqrestore(struct task_struct *t, unsigned long flags)
raw_spin_unlock_irqrestore_rcu_node(rnp, flags);
}
/* Unboost if we were boosted. */
if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex)
rt_mutex_futex_unlock(&rnp->boost_mtx.rtmutex);
/*
* If this was the last task on the expedited lists,
* then we need to report up the rcu_node hierarchy.
*/
if (!empty_exp && empty_exp_now)
rcu_report_exp_rnp(rnp, true);
/* Unboost if we were boosted. */
if (IS_ENABLED(CONFIG_RCU_BOOST) && drop_boost_mutex)
rt_mutex_futex_unlock(&rnp->boost_mtx.rtmutex);
} else {
local_irq_restore(flags);
}
......@@ -773,7 +773,6 @@ dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
int cpu;
int i;
struct list_head *lhp;
bool onl;
struct rcu_data *rdp;
struct rcu_node *rnp1;
......@@ -797,9 +796,8 @@ dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
pr_cont("\n");
for (cpu = rnp->grplo; cpu <= rnp->grphi; cpu++) {
rdp = per_cpu_ptr(&rcu_data, cpu);
onl = !!(rdp->grpmask & rcu_rnp_online_cpus(rnp));
pr_info("\t%d: %c online: %ld(%d) offline: %ld(%d)\n",
cpu, ".o"[onl],
cpu, ".o"[rcu_rdp_cpu_online(rdp)],
(long)rdp->rcu_onl_gp_seq, rdp->rcu_onl_gp_flags,
(long)rdp->rcu_ofl_gp_seq, rdp->rcu_ofl_gp_flags);
}
......@@ -996,12 +994,15 @@ dump_blkd_tasks(struct rcu_node *rnp, int ncheck)
*/
static void rcu_cpu_kthread_setup(unsigned int cpu)
{
struct rcu_data *rdp = per_cpu_ptr(&rcu_data, cpu);
#ifdef CONFIG_RCU_BOOST
struct sched_param sp;
sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(current, SCHED_FIFO, &sp);
#endif /* #ifdef CONFIG_RCU_BOOST */
WRITE_ONCE(rdp->rcuc_activity, jiffies);
}
#ifdef CONFIG_RCU_BOOST
......@@ -1172,15 +1173,14 @@ static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
struct sched_param sp;
struct task_struct *t;
mutex_lock(&rnp->boost_kthread_mutex);
if (rnp->boost_kthread_task || !rcu_scheduler_fully_active)
return;
rcu_state.boost = 1;
goto out;
t = kthread_create(rcu_boost_kthread, (void *)rnp,
"rcub/%d", rnp_index);
if (WARN_ON_ONCE(IS_ERR(t)))
return;
goto out;
raw_spin_lock_irqsave_rcu_node(rnp, flags);
rnp->boost_kthread_task = t;
......@@ -1188,6 +1188,9 @@ static void rcu_spawn_one_boost_kthread(struct rcu_node *rnp)
sp.sched_priority = kthread_prio;
sched_setscheduler_nocheck(t, SCHED_FIFO, &sp);
wake_up_process(t); /* get to TASK_INTERRUPTIBLE quickly. */
out:
mutex_unlock(&rnp->boost_kthread_mutex);
}
/*
......@@ -1210,14 +1213,16 @@ static void rcu_boost_kthread_setaffinity(struct rcu_node *rnp, int outgoingcpu)
return;
if (!zalloc_cpumask_var(&cm, GFP_KERNEL))
return;
mutex_lock(&rnp->boost_kthread_mutex);
for_each_leaf_node_possible_cpu(rnp, cpu)
if ((mask & leaf_node_cpu_bit(rnp, cpu)) &&
cpu != outgoingcpu)
cpumask_set_cpu(cpu, cm);
cpumask_and(cm, cm, housekeeping_cpumask(HK_FLAG_RCU));
if (cpumask_weight(cm) == 0)
if (cpumask_empty(cm))
cpumask_copy(cm, housekeeping_cpumask(HK_FLAG_RCU));
set_cpus_allowed_ptr(t, cm);
mutex_unlock(&rnp->boost_kthread_mutex);
free_cpumask_var(cm);
}
......
......@@ -379,6 +379,15 @@ static bool rcu_is_gp_kthread_starving(unsigned long *jp)
return j > 2 * HZ;
}
static bool rcu_is_rcuc_kthread_starving(struct rcu_data *rdp, unsigned long *jp)
{
unsigned long j = jiffies - READ_ONCE(rdp->rcuc_activity);
if (jp)
*jp = j;
return j > 2 * HZ;
}
/*
* Print out diagnostic information for the specified stalled CPU.
*
......@@ -430,6 +439,29 @@ static void print_cpu_stall_info(int cpu)
falsepositive ? " (false positive?)" : "");
}
static void rcuc_kthread_dump(struct rcu_data *rdp)
{
int cpu;
unsigned long j;
struct task_struct *rcuc;
rcuc = rdp->rcu_cpu_kthread_task;
if (!rcuc)
return;
cpu = task_cpu(rcuc);
if (cpu_is_offline(cpu) || idle_cpu(cpu))
return;
if (!rcu_is_rcuc_kthread_starving(rdp, &j))
return;
pr_err("%s kthread starved for %ld jiffies\n", rcuc->comm, j);
sched_show_task(rcuc);
if (!trigger_single_cpu_backtrace(cpu))
dump_cpu_task(cpu);
}
/* Complain about starvation of grace-period kthread. */
static void rcu_check_gp_kthread_starvation(void)
{
......@@ -601,6 +633,9 @@ static void print_cpu_stall(unsigned long gps)
rcu_check_gp_kthread_expired_fqs_timer();
rcu_check_gp_kthread_starvation();
if (!use_softirq)
rcuc_kthread_dump(rdp);
rcu_dump_cpu_stacks();
raw_spin_lock_irqsave_rcu_node(rnp, flags);
......
......@@ -407,6 +407,13 @@ void __wait_rcu_gp(bool checktiny, int n, call_rcu_func_t *crcu_array,
}
EXPORT_SYMBOL_GPL(__wait_rcu_gp);
void finish_rcuwait(struct rcuwait *w)
{
rcu_assign_pointer(w->task, NULL);
__set_current_state(TASK_RUNNING);
}
EXPORT_SYMBOL_GPL(finish_rcuwait);
#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD
void init_rcu_head(struct rcu_head *head)
{
......
......@@ -911,7 +911,7 @@ void torture_kthread_stopping(char *title)
{
char buf[128];
snprintf(buf, sizeof(buf), "Stopping %s", title);
snprintf(buf, sizeof(buf), "%s is stopping", title);
VERBOSE_TOROUT_STRING(buf);
while (!kthread_should_stop()) {
torture_shutdown_absorb(title);
......@@ -931,12 +931,14 @@ int _torture_create_kthread(int (*fn)(void *arg), void *arg, char *s, char *m,
int ret = 0;
VERBOSE_TOROUT_STRING(m);
*tp = kthread_run(fn, arg, "%s", s);
*tp = kthread_create(fn, arg, "%s", s);
if (IS_ERR(*tp)) {
ret = PTR_ERR(*tp);
TOROUT_ERRSTRING(f);
*tp = NULL;
return ret;
}
wake_up_process(*tp); // Process is sleeping, so ordering provided.
torture_shuffle_task_register(*tp);
return ret;
}
......
......@@ -10,7 +10,7 @@
#
# Authors: Paul E. McKenney <paulmck@kernel.org>
egrep 'Badness|WARNING:|Warn|BUG|===========|Call Trace:|Oops:|detected stalls on CPUs/tasks:|self-detected stall on CPU|Stall ended before state dump start|\?\?\? Writer stall state|rcu_.*kthread starved for|!!!' |
egrep 'Badness|WARNING:|Warn|BUG|===========|BUG: KCSAN:|Call Trace:|Oops:|detected stalls on CPUs/tasks:|self-detected stall on CPU|Stall ended before state dump start|\?\?\? Writer stall state|rcu_.*kthread starved for|!!!' |
grep -v 'ODEBUG: ' |
grep -v 'This means that this is a DEBUG kernel and it is' |
grep -v 'Warning: unable to open an initial console' |
......
......@@ -47,8 +47,8 @@ else
exit 1
fi
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
PATH=${RCUTORTURE}/bin:$PATH; export PATH
. functions.sh
dryrun=
......
......@@ -49,8 +49,8 @@ fi
mkdir $resdir/$ds
echo Results directory: $resdir/$ds
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
PATH=${RCUTORTURE}/bin:$PATH; export PATH
. functions.sh
echo Using all `identify_qemu_vcpus` CPUs.
......
......@@ -22,8 +22,8 @@ T=${TMPDIR-/tmp}/kvm-end-run-stats.sh.$$
trap 'rm -rf $T' 0
mkdir $T
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
PATH=${RCUTORTURE}/bin:$PATH; export PATH
. functions.sh
default_starttime="`get_starttime`"
starttime="${2-default_starttime}"
......
......@@ -30,10 +30,16 @@ editor=${EDITOR-vi}
files=
for i in ${rundir}/*/Make.out
do
scenariodir="`dirname $i`"
scenariobasedir="`echo ${scenariodir} | sed -e 's/\.[0-9]*$//'`"
if egrep -q "error:|warning:|^ld: .*undefined reference to" < $i
then
egrep "error:|warning:|^ld: .*undefined reference to" < $i > $i.diags
files="$files $i.diags $i"
elif ! test -f ${scenariobasedir}/vmlinux
then
echo No ${scenariobasedir}/vmlinux file > $i.diags
files="$files $i.diags $i"
fi
done
if test -n "$files"
......
......@@ -25,7 +25,7 @@ stopstate="`grep 'End-test grace-period state: g' $i/console.log 2> /dev/null |
tail -1 | sed -e 's/^\[[ 0-9.]*] //' |
awk '{ print \"[\" $1 \" \" $5 \" \" $6 \" \" $7 \"]\"; }' |
tr -d '\012\015'`"
fwdprog="`grep 'rcu_torture_fwd_prog n_max_cbs: ' $i/console.log 2> /dev/null | sed -e 's/^\[[^]]*] //' | sort -k3nr | head -1 | awk '{ print $2 " " $3 }'`"
fwdprog="`grep 'rcu_torture_fwd_prog n_max_cbs: ' $i/console.log 2> /dev/null | sed -e 's/^\[[^]]*] //' | sort -k3nr | head -1 | awk '{ print $2 " " $3 }' | tr -d '\015'`"
if test -z "$ngps"
then
echo "$configfile ------- " $stopstate
......
......@@ -19,8 +19,8 @@ then
exit 1
fi
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
PATH=${RCUTORTURE}/bin:$PATH; export PATH
. functions.sh
starttime="`get_starttime`"
......@@ -108,8 +108,8 @@ else
cat $T/kvm-again.sh.out | tee -a "$oldrun/remote-log"
exit 2
fi
cp -a "$rundir" "$KVM/res/"
oldrun="$KVM/res/$ds"
cp -a "$rundir" "$RCUTORTURE/res/"
oldrun="$RCUTORTURE/res/$ds"
fi
echo | tee -a "$oldrun/remote-log"
echo " ----" kvm-again.sh output: "(`date`)" | tee -a "$oldrun/remote-log"
......@@ -155,18 +155,23 @@ do
echo Downloading tarball to $i `date` | tee -a "$oldrun/remote-log"
cat $T/binres.tgz | ssh $i "cd /tmp; tar -xzf -"
ret=$?
if test "$ret" -ne 0
then
echo Unable to download $T/binres.tgz to system $i, waiting and then retrying. | tee -a "$oldrun/remote-log"
tries=0
while test "$ret" -ne 0
do
echo Unable to download $T/binres.tgz to system $i, waiting and then retrying. $tries prior retries. | tee -a "$oldrun/remote-log"
sleep 60
cat $T/binres.tgz | ssh $i "cd /tmp; tar -xzf -"
ret=$?
if test "$ret" -ne 0
then
echo Unable to download $T/binres.tgz to system $i, giving up. | tee -a "$oldrun/remote-log"
exit 10
if test "$tries" > 5
then
echo Unable to download $T/binres.tgz to system $i, giving up. | tee -a "$oldrun/remote-log"
exit 10
fi
fi
fi
tries=$((tries+1))
done
done
# Function to check for presence of a file on the specified system.
......
......@@ -25,15 +25,15 @@ LANG=en_US.UTF-8; export LANG
dur=$((30*60))
dryrun=""
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
PATH=${RCUTORTURE}/bin:$PATH; export PATH
. functions.sh
TORTURE_ALLOTED_CPUS="`identify_qemu_vcpus`"
TORTURE_DEFCONFIG=defconfig
TORTURE_BOOT_IMAGE=""
TORTURE_BUILDONLY=
TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD
TORTURE_INITRD="$RCUTORTURE/initrd"; export TORTURE_INITRD
TORTURE_KCONFIG_ARG=""
TORTURE_KCONFIG_GDB_ARG=""
TORTURE_BOOT_GDB_ARG=""
......@@ -262,7 +262,7 @@ else
exit 1
fi
CONFIGFRAG=${KVM}/configs/${TORTURE_SUITE}; export CONFIGFRAG
CONFIGFRAG=${RCUTORTURE}/configs/${TORTURE_SUITE}; export CONFIGFRAG
defaultconfigs="`tr '\012' ' ' < $CONFIGFRAG/CFLIST`"
if test -z "$configs"
......@@ -272,7 +272,7 @@ fi
if test -z "$resdir"
then
resdir=$KVM/res
resdir=$RCUTORTURE/res
fi
# Create a file of test-name/#cpus pairs, sorted by decreasing #cpus.
......@@ -280,7 +280,7 @@ configs_derep=
for CF in $configs
do
case $CF in
[0-9]\**|[0-9][0-9]\**|[0-9][0-9][0-9]\**)
[0-9]\**|[0-9][0-9]\**|[0-9][0-9][0-9]\**|[0-9][0-9][0-9][0-9]\**)
config_reps=`echo $CF | sed -e 's/\*.*$//'`
CF1=`echo $CF | sed -e 's/^[^*]*\*//'`
;;
......@@ -386,7 +386,7 @@ END {
# Generate a script to execute the tests in appropriate batches.
cat << ___EOF___ > $T/script
CONFIGFRAG="$CONFIGFRAG"; export CONFIGFRAG
KVM="$KVM"; export KVM
RCUTORTURE="$RCUTORTURE"; export RCUTORTURE
PATH="$PATH"; export PATH
TORTURE_ALLOTED_CPUS="$TORTURE_ALLOTED_CPUS"; export TORTURE_ALLOTED_CPUS
TORTURE_BOOT_IMAGE="$TORTURE_BOOT_IMAGE"; export TORTURE_BOOT_IMAGE
......@@ -569,7 +569,7 @@ ___EOF___
awk < $T/cfgcpu.pack \
-v TORTURE_BUILDONLY="$TORTURE_BUILDONLY" \
-v CONFIGDIR="$CONFIGFRAG/" \
-v KVM="$KVM" \
-v RCUTORTURE="$RCUTORTURE" \
-v ncpus=$cpus \
-v jitter="$jitter" \
-v rd=$resdir/$ds/ \
......
......@@ -138,6 +138,16 @@ then
then
summary="$summary Bugs: $n_bugs"
fi
n_kcsan=`egrep -c 'BUG: KCSAN: ' $file`
if test "$n_kcsan" -ne 0
then
if test "$n_bugs" = "$n_kcsan"
then
summary="$summary (all bugs kcsan)"
else
summary="$summary KCSAN: $n_kcsan"
fi
fi
n_calltrace=`grep -c 'Call Trace:' $file`
if test "$n_calltrace" -ne 0
then
......
......@@ -13,8 +13,8 @@
scriptname=$0
args="$*"
KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM
PATH=${KVM}/bin:$PATH; export PATH
RCUTORTURE="`pwd`/tools/testing/selftests/rcutorture"; export RCUTORTURE
PATH=${RCUTORTURE}/bin:$PATH; export PATH
. functions.sh
TORTURE_ALLOTED_CPUS="`identify_qemu_vcpus`"
......@@ -37,7 +37,7 @@ configs_scftorture=
kcsan_kmake_args=
# Default compression, duration, and apportionment.
compress_kasan_vmlinux="`identify_qemu_vcpus`"
compress_concurrency="`identify_qemu_vcpus`"
duration_base=10
duration_rcutorture_frac=7
duration_locktorture_frac=1
......@@ -67,12 +67,12 @@ function doyesno () {
usage () {
echo "Usage: $scriptname optional arguments:"
echo " --compress-kasan-vmlinux concurrency"
echo " --compress-concurrency concurrency"
echo " --configs-rcutorture \"config-file list w/ repeat factor (3*TINY01)\""
echo " --configs-locktorture \"config-file list w/ repeat factor (10*LOCK01)\""
echo " --configs-scftorture \"config-file list w/ repeat factor (2*CFLIST)\""
echo " --doall"
echo " --doallmodconfig / --do-no-allmodconfig"
echo " --do-all"
echo " --do-allmodconfig / --do-no-allmodconfig"
echo " --do-clocksourcewd / --do-no-clocksourcewd"
echo " --do-kasan / --do-no-kasan"
echo " --do-kcsan / --do-no-kcsan"
......@@ -91,9 +91,9 @@ usage () {
while test $# -gt 0
do
case "$1" in
--compress-kasan-vmlinux)
checkarg --compress-kasan-vmlinux "(concurrency level)" $# "$2" '^[0-9][0-9]*$' '^error'
compress_kasan_vmlinux=$2
--compress-concurrency)
checkarg --compress-concurrency "(concurrency level)" $# "$2" '^[0-9][0-9]*$' '^error'
compress_concurrency=$2
shift
;;
--config-rcutorture|--configs-rcutorture)
......@@ -414,8 +414,14 @@ nfailures=0
echo FAILURES: | tee -a $T/log
if test -s "$T/failures"
then
cat "$T/failures" | tee -a $T/log
awk < "$T/failures" -v sq="'" '{ print "echo " sq $0 sq; print "sed -e " sq "1,/^ --- .* Test summary:$/d" sq " " $2 "/log | grep Summary: | sed -e " sq "s/^[^S]*/ /" sq; }' | sh | tee -a $T/log | tee "$T/failuresum"
nfailures="`wc -l "$T/failures" | awk '{ print $1 }'`"
grep "^ Summary: " "$T/failuresum" |
grep -v '^ Summary: Bugs: [0-9]* (all bugs kcsan)$' > "$T/nonkcsan"
if test -s "$T/nonkcsan"
then
nonkcsanbug="yes"
fi
ret=2
fi
if test "$do_kcsan" = "yes"
......@@ -424,12 +430,16 @@ then
fi
echo Started at $startdate, ended at `date`, duration `get_starttime_duration $starttime`. | tee -a $T/log
echo Summary: Successes: $nsuccesses Failures: $nfailures. | tee -a $T/log
if test -z "$nonkcsanbug" && test -s "$T/failuresum"
then
echo " All bugs were KCSAN failures."
fi
tdir="`cat $T/successes $T/failures | head -1 | awk '{ print $NF }' | sed -e 's,/[^/]\+/*$,,'`"
if test -n "$tdir" && test $compress_kasan_vmlinux -gt 0
if test -n "$tdir" && test $compress_concurrency -gt 0
then
# KASAN vmlinux files can approach 1GB in size, so compress them.
echo Looking for KASAN files to compress: `date` > "$tdir/log-xz" 2>&1
find "$tdir" -type d -name '*-kasan' -print > $T/xz-todo
echo Looking for K[AC]SAN files to compress: `date` > "$tdir/log-xz" 2>&1
find "$tdir" -type d -name '*-k[ac]san' -print > $T/xz-todo
ncompresses=0
batchno=1
if test -s $T/xz-todo
......@@ -447,7 +457,7 @@ then
do
xz "$j" >> "$tdir/log-xz" 2>&1 &
ncompresses=$((ncompresses+1))
if test $ncompresses -ge $compress_kasan_vmlinux
if test $ncompresses -ge $compress_concurrency
then
echo Waiting for batch $batchno of $ncompresses compressions `date` | tee -a "$tdir/log-xz" | tee -a $T/log
wait
......
CONFIG_SMP=y
CONFIG_NR_CPUS=4
CONFIG_NR_CPUS=3
CONFIG_HOTPLUG_CPU=y
CONFIG_PREEMPT_NONE=n
CONFIG_PREEMPT_VOLUNTARY=n
......
rcutorture.torture_type=srcu
rcutorture.fwd_progress=3
rcutorture.torture_type=srcud
rcupdate.rcu_self_test=1
rcutorture.fwd_progress=3
srcutree.big_cpu_lim=5
CONFIG_SMP=y
CONFIG_NR_CPUS=4
CONFIG_NR_CPUS=5
CONFIG_HOTPLUG_CPU=y
CONFIG_PREEMPT_NONE=y
CONFIG_PREEMPT_VOLUNTARY=n
......
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