#include <linux/sched/clock.h>
#include <linux/nmi.h>
#include <linux/sched/debug.h>
+#include <linux/jump_label.h>
#include "smpboot.h"
#include "sched/smp.h"
#define CSD_TYPE(_csd) ((_csd)->node.u_flags & CSD_FLAG_TYPE_MASK)
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+union cfd_seq_cnt {
+ u64 val;
+ struct {
+ u64 src:16;
+ u64 dst:16;
+#define CFD_SEQ_NOCPU 0xffff
+ u64 type:4;
+#define CFD_SEQ_QUEUE 0
+#define CFD_SEQ_IPI 1
+#define CFD_SEQ_NOIPI 2
+#define CFD_SEQ_PING 3
+#define CFD_SEQ_PINGED 4
+#define CFD_SEQ_HANDLE 5
+#define CFD_SEQ_DEQUEUE 6
+#define CFD_SEQ_IDLE 7
+#define CFD_SEQ_GOTIPI 8
+#define CFD_SEQ_HDLEND 9
+ u64 cnt:28;
+ } u;
+};
+
+static char *seq_type[] = {
+ [CFD_SEQ_QUEUE] = "queue",
+ [CFD_SEQ_IPI] = "ipi",
+ [CFD_SEQ_NOIPI] = "noipi",
+ [CFD_SEQ_PING] = "ping",
+ [CFD_SEQ_PINGED] = "pinged",
+ [CFD_SEQ_HANDLE] = "handle",
+ [CFD_SEQ_DEQUEUE] = "dequeue (src CPU 0 == empty)",
+ [CFD_SEQ_IDLE] = "idle",
+ [CFD_SEQ_GOTIPI] = "gotipi",
+ [CFD_SEQ_HDLEND] = "hdlend (src CPU 0 == early)",
+};
+
+struct cfd_seq_local {
+ u64 ping;
+ u64 pinged;
+ u64 handle;
+ u64 dequeue;
+ u64 idle;
+ u64 gotipi;
+ u64 hdlend;
+};
+#endif
+
+struct cfd_percpu {
+ call_single_data_t csd;
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+ u64 seq_queue;
+ u64 seq_ipi;
+ u64 seq_noipi;
+#endif
+};
+
struct call_function_data {
- call_single_data_t __percpu *csd;
+ struct cfd_percpu __percpu *pcpu;
cpumask_var_t cpumask;
cpumask_var_t cpumask_ipi;
};
free_cpumask_var(cfd->cpumask);
return -ENOMEM;
}
- cfd->csd = alloc_percpu(call_single_data_t);
- if (!cfd->csd) {
+ cfd->pcpu = alloc_percpu(struct cfd_percpu);
+ if (!cfd->pcpu) {
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
return -ENOMEM;
free_cpumask_var(cfd->cpumask);
free_cpumask_var(cfd->cpumask_ipi);
- free_percpu(cfd->csd);
+ free_percpu(cfd->pcpu);
return 0;
}
#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+static DEFINE_STATIC_KEY_FALSE(csdlock_debug_enabled);
+static DEFINE_STATIC_KEY_FALSE(csdlock_debug_extended);
+
+static int __init csdlock_debug(char *str)
+{
+ unsigned int val = 0;
+
+ if (str && !strcmp(str, "ext")) {
+ val = 1;
+ static_branch_enable(&csdlock_debug_extended);
+ } else
+ get_option(&str, &val);
+
+ if (val)
+ static_branch_enable(&csdlock_debug_enabled);
+
+ return 0;
+}
+early_param("csdlock_debug", csdlock_debug);
+
static DEFINE_PER_CPU(call_single_data_t *, cur_csd);
static DEFINE_PER_CPU(smp_call_func_t, cur_csd_func);
static DEFINE_PER_CPU(void *, cur_csd_info);
+static DEFINE_PER_CPU(struct cfd_seq_local, cfd_seq_local);
#define CSD_LOCK_TIMEOUT (5ULL * NSEC_PER_SEC)
static atomic_t csd_bug_count = ATOMIC_INIT(0);
+static u64 cfd_seq;
+
+#define CFD_SEQ(s, d, t, c) \
+ (union cfd_seq_cnt){ .u.src = s, .u.dst = d, .u.type = t, .u.cnt = c }
+
+static u64 cfd_seq_inc(unsigned int src, unsigned int dst, unsigned int type)
+{
+ union cfd_seq_cnt new, old;
+
+ new = CFD_SEQ(src, dst, type, 0);
+
+ do {
+ old.val = READ_ONCE(cfd_seq);
+ new.u.cnt = old.u.cnt + 1;
+ } while (cmpxchg(&cfd_seq, old.val, new.val) != old.val);
+
+ return old.val;
+}
+
+#define cfd_seq_store(var, src, dst, type) \
+ do { \
+ if (static_branch_unlikely(&csdlock_debug_extended)) \
+ var = cfd_seq_inc(src, dst, type); \
+ } while (0)
/* Record current CSD work for current CPU, NULL to erase. */
-static void csd_lock_record(call_single_data_t *csd)
+static void __csd_lock_record(call_single_data_t *csd)
{
if (!csd) {
smp_mb(); /* NULL cur_csd after unlock. */
/* Or before unlock, as the case may be. */
}
-static __always_inline int csd_lock_wait_getcpu(call_single_data_t *csd)
+static __always_inline void csd_lock_record(call_single_data_t *csd)
+{
+ if (static_branch_unlikely(&csdlock_debug_enabled))
+ __csd_lock_record(csd);
+}
+
+static int csd_lock_wait_getcpu(call_single_data_t *csd)
{
unsigned int csd_type;
return -1;
}
+static void cfd_seq_data_add(u64 val, unsigned int src, unsigned int dst,
+ unsigned int type, union cfd_seq_cnt *data,
+ unsigned int *n_data, unsigned int now)
+{
+ union cfd_seq_cnt new[2];
+ unsigned int i, j, k;
+
+ new[0].val = val;
+ new[1] = CFD_SEQ(src, dst, type, new[0].u.cnt + 1);
+
+ for (i = 0; i < 2; i++) {
+ if (new[i].u.cnt <= now)
+ new[i].u.cnt |= 0x80000000U;
+ for (j = 0; j < *n_data; j++) {
+ if (new[i].u.cnt == data[j].u.cnt) {
+ /* Direct read value trumps generated one. */
+ if (i == 0)
+ data[j].val = new[i].val;
+ break;
+ }
+ if (new[i].u.cnt < data[j].u.cnt) {
+ for (k = *n_data; k > j; k--)
+ data[k].val = data[k - 1].val;
+ data[j].val = new[i].val;
+ (*n_data)++;
+ break;
+ }
+ }
+ if (j == *n_data) {
+ data[j].val = new[i].val;
+ (*n_data)++;
+ }
+ }
+}
+
+static const char *csd_lock_get_type(unsigned int type)
+{
+ return (type >= ARRAY_SIZE(seq_type)) ? "?" : seq_type[type];
+}
+
+static void csd_lock_print_extended(call_single_data_t *csd, int cpu)
+{
+ struct cfd_seq_local *seq = &per_cpu(cfd_seq_local, cpu);
+ unsigned int srccpu = csd->node.src;
+ struct call_function_data *cfd = per_cpu_ptr(&cfd_data, srccpu);
+ struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+ unsigned int now;
+ union cfd_seq_cnt data[2 * ARRAY_SIZE(seq_type)];
+ unsigned int n_data = 0, i;
+
+ data[0].val = READ_ONCE(cfd_seq);
+ now = data[0].u.cnt;
+
+ cfd_seq_data_add(pcpu->seq_queue, srccpu, cpu, CFD_SEQ_QUEUE, data, &n_data, now);
+ cfd_seq_data_add(pcpu->seq_ipi, srccpu, cpu, CFD_SEQ_IPI, data, &n_data, now);
+ cfd_seq_data_add(pcpu->seq_noipi, srccpu, cpu, CFD_SEQ_NOIPI, data, &n_data, now);
+
+ cfd_seq_data_add(per_cpu(cfd_seq_local.ping, srccpu), srccpu, CFD_SEQ_NOCPU, CFD_SEQ_PING, data, &n_data, now);
+ cfd_seq_data_add(per_cpu(cfd_seq_local.pinged, srccpu), srccpu, CFD_SEQ_NOCPU, CFD_SEQ_PINGED, data, &n_data, now);
+
+ cfd_seq_data_add(seq->idle, CFD_SEQ_NOCPU, cpu, CFD_SEQ_IDLE, data, &n_data, now);
+ cfd_seq_data_add(seq->gotipi, CFD_SEQ_NOCPU, cpu, CFD_SEQ_GOTIPI, data, &n_data, now);
+ cfd_seq_data_add(seq->handle, CFD_SEQ_NOCPU, cpu, CFD_SEQ_HANDLE, data, &n_data, now);
+ cfd_seq_data_add(seq->dequeue, CFD_SEQ_NOCPU, cpu, CFD_SEQ_DEQUEUE, data, &n_data, now);
+ cfd_seq_data_add(seq->hdlend, CFD_SEQ_NOCPU, cpu, CFD_SEQ_HDLEND, data, &n_data, now);
+
+ for (i = 0; i < n_data; i++) {
+ pr_alert("\tcsd: cnt(%07x): %04x->%04x %s\n",
+ data[i].u.cnt & ~0x80000000U, data[i].u.src,
+ data[i].u.dst, csd_lock_get_type(data[i].u.type));
+ }
+ pr_alert("\tcsd: cnt now: %07x\n", now);
+}
+
/*
* Complain if too much time spent waiting. Note that only
* the CSD_TYPE_SYNC/ASYNC types provide the destination CPU,
* so waiting on other types gets much less information.
*/
-static __always_inline bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, int *bug_id)
+static bool csd_lock_wait_toolong(call_single_data_t *csd, u64 ts0, u64 *ts1, int *bug_id)
{
int cpu = -1;
int cpux;
*bug_id, !cpu_cur_csd ? "unresponsive" : "handling this request");
}
if (cpu >= 0) {
+ if (static_branch_unlikely(&csdlock_debug_extended))
+ csd_lock_print_extended(csd, cpu);
if (!trigger_single_cpu_backtrace(cpu))
dump_cpu_task(cpu);
if (!cpu_cur_csd) {
* previous function call. For multi-cpu calls its even more interesting
* as we'll have to ensure no other cpu is observing our csd.
*/
-static __always_inline void csd_lock_wait(call_single_data_t *csd)
+static void __csd_lock_wait(call_single_data_t *csd)
{
int bug_id = 0;
u64 ts0, ts1;
smp_acquire__after_ctrl_dep();
}
+static __always_inline void csd_lock_wait(call_single_data_t *csd)
+{
+ if (static_branch_unlikely(&csdlock_debug_enabled)) {
+ __csd_lock_wait(csd);
+ return;
+ }
+
+ smp_cond_load_acquire(&csd->node.u_flags, !(VAL & CSD_FLAG_LOCK));
+}
+
+static void __smp_call_single_queue_debug(int cpu, struct llist_node *node)
+{
+ unsigned int this_cpu = smp_processor_id();
+ struct cfd_seq_local *seq = this_cpu_ptr(&cfd_seq_local);
+ struct call_function_data *cfd = this_cpu_ptr(&cfd_data);
+ struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+
+ cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
+ if (llist_add(node, &per_cpu(call_single_queue, cpu))) {
+ cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
+ cfd_seq_store(seq->ping, this_cpu, cpu, CFD_SEQ_PING);
+ send_call_function_single_ipi(cpu);
+ cfd_seq_store(seq->pinged, this_cpu, cpu, CFD_SEQ_PINGED);
+ } else {
+ cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
+ }
+}
#else
+#define cfd_seq_store(var, src, dst, type)
+
static void csd_lock_record(call_single_data_t *csd)
{
}
void __smp_call_single_queue(int cpu, struct llist_node *node)
{
+#ifdef CONFIG_CSD_LOCK_WAIT_DEBUG
+ if (static_branch_unlikely(&csdlock_debug_extended)) {
+ unsigned int type;
+
+ type = CSD_TYPE(container_of(node, call_single_data_t,
+ node.llist));
+ if (type == CSD_TYPE_SYNC || type == CSD_TYPE_ASYNC) {
+ __smp_call_single_queue_debug(cpu, node);
+ return;
+ }
+ }
+#endif
+
/*
* The list addition should be visible before sending the IPI
* handler locks the list to pull the entry off it because of
*/
void generic_smp_call_function_single_interrupt(void)
{
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->gotipi, CFD_SEQ_NOCPU,
+ smp_processor_id(), CFD_SEQ_GOTIPI);
flush_smp_call_function_queue(true);
}
lockdep_assert_irqs_disabled();
head = this_cpu_ptr(&call_single_queue);
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->handle, CFD_SEQ_NOCPU,
+ smp_processor_id(), CFD_SEQ_HANDLE);
entry = llist_del_all(head);
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->dequeue,
+ /* Special meaning of source cpu: 0 == queue empty */
+ entry ? CFD_SEQ_NOCPU : 0,
+ smp_processor_id(), CFD_SEQ_DEQUEUE);
entry = llist_reverse_order(entry);
/* There shouldn't be any pending callbacks on an offline CPU. */
}
}
- if (!entry)
+ if (!entry) {
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->hdlend,
+ 0, smp_processor_id(),
+ CFD_SEQ_HDLEND);
return;
+ }
/*
* Second; run all !SYNC callbacks.
*/
if (entry)
sched_ttwu_pending(entry);
+
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->hdlend, CFD_SEQ_NOCPU,
+ smp_processor_id(), CFD_SEQ_HDLEND);
}
void flush_smp_call_function_from_idle(void)
if (llist_empty(this_cpu_ptr(&call_single_queue)))
return;
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->idle, CFD_SEQ_NOCPU,
+ smp_processor_id(), CFD_SEQ_IDLE);
local_irq_save(flags);
flush_smp_call_function_queue(true);
if (local_softirq_pending())
cpumask_clear(cfd->cpumask_ipi);
for_each_cpu(cpu, cfd->cpumask) {
- call_single_data_t *csd = per_cpu_ptr(cfd->csd, cpu);
+ struct cfd_percpu *pcpu = per_cpu_ptr(cfd->pcpu, cpu);
+ call_single_data_t *csd = &pcpu->csd;
if (cond_func && !cond_func(cpu, info))
continue;
csd->node.src = smp_processor_id();
csd->node.dst = cpu;
#endif
- if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu)))
+ cfd_seq_store(pcpu->seq_queue, this_cpu, cpu, CFD_SEQ_QUEUE);
+ if (llist_add(&csd->node.llist, &per_cpu(call_single_queue, cpu))) {
__cpumask_set_cpu(cpu, cfd->cpumask_ipi);
+ cfd_seq_store(pcpu->seq_ipi, this_cpu, cpu, CFD_SEQ_IPI);
+ } else {
+ cfd_seq_store(pcpu->seq_noipi, this_cpu, cpu, CFD_SEQ_NOIPI);
+ }
}
/* Send a message to all CPUs in the map */
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->ping, this_cpu,
+ CFD_SEQ_NOCPU, CFD_SEQ_PING);
arch_send_call_function_ipi_mask(cfd->cpumask_ipi);
+ cfd_seq_store(this_cpu_ptr(&cfd_seq_local)->pinged, this_cpu,
+ CFD_SEQ_NOCPU, CFD_SEQ_PINGED);
if (wait) {
for_each_cpu(cpu, cfd->cpumask) {
call_single_data_t *csd;
- csd = per_cpu_ptr(cfd->csd, cpu);
+ csd = &per_cpu_ptr(cfd->pcpu, cpu)->csd;
csd_lock_wait(csd);
}
}
projects / linux-2.6-microblaze.git / blobdiff