diff options
| -rw-r--r-- | include/trace/events/rcu.h | 345 | ||||
| -rw-r--r-- | kernel/rcu.h | 6 | ||||
| -rw-r--r-- | kernel/rcutiny.c | 4 | ||||
| -rw-r--r-- | kernel/rcutree.c | 45 | ||||
| -rw-r--r-- | kernel/rcutree.h | 1 | ||||
| -rw-r--r-- | kernel/rcutree_plugin.h | 22 |
6 files changed, 399 insertions, 24 deletions
diff --git a/include/trace/events/rcu.h b/include/trace/events/rcu.h index ac52aba00a3..669fbd62ec2 100644 --- a/include/trace/events/rcu.h +++ b/include/trace/events/rcu.h @@ -24,7 +24,7 @@ TRACE_EVENT(rcu_utilization, TP_ARGS(s), TP_STRUCT__entry( - __field(char *, s) + __field(char *, s) ), TP_fast_assign( @@ -34,6 +34,297 @@ TRACE_EVENT(rcu_utilization, TP_printk("%s", __entry->s) ); +#ifdef CONFIG_RCU_TRACE + +#if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) + +/* + * Tracepoint for grace-period events: starting and ending a grace + * period ("start" and "end", respectively), a CPU noting the start + * of a new grace period or the end of an old grace period ("cpustart" + * and "cpuend", respectively), a CPU passing through a quiescent + * state ("cpuqs"), a CPU coming online or going offline ("cpuonl" + * and "cpuofl", respectively), and a CPU being kicked for being too + * long in dyntick-idle mode ("kick"). + */ +TRACE_EVENT(rcu_grace_period, + + TP_PROTO(char *rcuname, unsigned long gpnum, char *gpevent), + + TP_ARGS(rcuname, gpnum, gpevent), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(unsigned long, gpnum) + __field(char *, gpevent) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->gpnum = gpnum; + __entry->gpevent = gpevent; + ), + + TP_printk("%s %lu %s", + __entry->rcuname, __entry->gpnum, __entry->gpevent) +); + +/* + * Tracepoint for grace-period-initialization events. These are + * distinguished by the type of RCU, the new grace-period number, the + * rcu_node structure level, the starting and ending CPU covered by the + * rcu_node structure, and the mask of CPUs that will be waited for. + * All but the type of RCU are extracted from the rcu_node structure. + */ +TRACE_EVENT(rcu_grace_period_init, + + TP_PROTO(char *rcuname, unsigned long gpnum, u8 level, + int grplo, int grphi, unsigned long qsmask), + + TP_ARGS(rcuname, gpnum, level, grplo, grphi, qsmask), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(unsigned long, gpnum) + __field(u8, level) + __field(int, grplo) + __field(int, grphi) + __field(unsigned long, qsmask) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->gpnum = gpnum; + __entry->level = level; + __entry->grplo = grplo; + __entry->grphi = grphi; + __entry->qsmask = qsmask; + ), + + TP_printk("%s %lu %u %d %d %lx", + __entry->rcuname, __entry->gpnum, __entry->level, + __entry->grplo, __entry->grphi, __entry->qsmask) +); + +/* + * Tracepoint for tasks blocking within preemptible-RCU read-side + * critical sections. Track the type of RCU (which one day might + * include SRCU), the grace-period number that the task is blocking + * (the current or the next), and the task's PID. + */ +TRACE_EVENT(rcu_preempt_task, + + TP_PROTO(char *rcuname, int pid, unsigned long gpnum), + + TP_ARGS(rcuname, pid, gpnum), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(unsigned long, gpnum) + __field(int, pid) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->gpnum = gpnum; + __entry->pid = pid; + ), + + TP_printk("%s %lu %d", + __entry->rcuname, __entry->gpnum, __entry->pid) +); + +/* + * Tracepoint for tasks that blocked within a given preemptible-RCU + * read-side critical section exiting that critical section. Track the + * type of RCU (which one day might include SRCU) and the task's PID. + */ +TRACE_EVENT(rcu_unlock_preempted_task, + + TP_PROTO(char *rcuname, unsigned long gpnum, int pid), + + TP_ARGS(rcuname, gpnum, pid), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(unsigned long, gpnum) + __field(int, pid) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->gpnum = gpnum; + __entry->pid = pid; + ), + + TP_printk("%s %lu %d", __entry->rcuname, __entry->gpnum, __entry->pid) +); + +/* + * Tracepoint for quiescent-state-reporting events. These are + * distinguished by the type of RCU, the grace-period number, the + * mask of quiescent lower-level entities, the rcu_node structure level, + * the starting and ending CPU covered by the rcu_node structure, and + * whether there are any blocked tasks blocking the current grace period. + * All but the type of RCU are extracted from the rcu_node structure. + */ +TRACE_EVENT(rcu_quiescent_state_report, + + TP_PROTO(char *rcuname, unsigned long gpnum, + unsigned long mask, unsigned long qsmask, + u8 level, int grplo, int grphi, int gp_tasks), + + TP_ARGS(rcuname, gpnum, mask, qsmask, level, grplo, grphi, gp_tasks), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(unsigned long, gpnum) + __field(unsigned long, mask) + __field(unsigned long, qsmask) + __field(u8, level) + __field(int, grplo) + __field(int, grphi) + __field(u8, gp_tasks) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->gpnum = gpnum; + __entry->mask = mask; + __entry->qsmask = qsmask; + __entry->level = level; + __entry->grplo = grplo; + __entry->grphi = grphi; + __entry->gp_tasks = gp_tasks; + ), + + TP_printk("%s %lu %lx>%lx %u %d %d %u", + __entry->rcuname, __entry->gpnum, + __entry->mask, __entry->qsmask, __entry->level, + __entry->grplo, __entry->grphi, __entry->gp_tasks) +); + +/* + * Tracepoint for quiescent states detected by force_quiescent_state(). + * These trace events include the type of RCU, the grace-period number + * that was blocked by the CPU, the CPU itself, and the type of quiescent + * state, which can be "dti" for dyntick-idle mode, "ofl" for CPU offline, + * or "kick" when kicking a CPU that has been in dyntick-idle mode for + * too long. + */ +TRACE_EVENT(rcu_fqs, + + TP_PROTO(char *rcuname, unsigned long gpnum, int cpu, char *qsevent), + + TP_ARGS(rcuname, gpnum, cpu, qsevent), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(unsigned long, gpnum) + __field(int, cpu) + __field(char *, qsevent) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->gpnum = gpnum; + __entry->cpu = cpu; + __entry->qsevent = qsevent; + ), + + TP_printk("%s %lu %d %s", + __entry->rcuname, __entry->gpnum, + __entry->cpu, __entry->qsevent) +); + +#endif /* #if defined(CONFIG_TREE_RCU) || defined(CONFIG_TREE_PREEMPT_RCU) */ + +/* + * Tracepoint for dyntick-idle entry/exit events. These take a string + * as argument: "Start" for entering dyntick-idle mode and "End" for + * leaving it. + */ +TRACE_EVENT(rcu_dyntick, + + TP_PROTO(char *polarity), + + TP_ARGS(polarity), + + TP_STRUCT__entry( + __field(char *, polarity) + ), + + TP_fast_assign( + __entry->polarity = polarity; + ), + + TP_printk("%s", __entry->polarity) +); + +/* + * Tracepoint for the registration of a single RCU callback function. + * The first argument is the type of RCU, the second argument is + * a pointer to the RCU callback itself, and the third element is the + * new RCU callback queue length for the current CPU. + */ +TRACE_EVENT(rcu_callback, + + TP_PROTO(char *rcuname, struct rcu_head *rhp, long qlen), + + TP_ARGS(rcuname, rhp, qlen), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(void *, rhp) + __field(void *, func) + __field(long, qlen) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->rhp = rhp; + __entry->func = rhp->func; + __entry->qlen = qlen; + ), + + TP_printk("%s rhp=%p func=%pf %ld", + __entry->rcuname, __entry->rhp, __entry->func, __entry->qlen) +); + +/* + * Tracepoint for the registration of a single RCU callback of the special + * kfree() form. The first argument is the RCU type, the second argument + * is a pointer to the RCU callback, the third argument is the offset + * of the callback within the enclosing RCU-protected data structure, + * and the fourth argument is the new RCU callback queue length for the + * current CPU. + */ +TRACE_EVENT(rcu_kfree_callback, + + TP_PROTO(char *rcuname, struct rcu_head *rhp, unsigned long offset, + long qlen), + + TP_ARGS(rcuname, rhp, offset, qlen), + + TP_STRUCT__entry( + __field(char *, rcuname) + __field(void *, rhp) + __field(unsigned long, offset) + __field(long, qlen) + ), + + TP_fast_assign( + __entry->rcuname = rcuname; + __entry->rhp = rhp; + __entry->offset = offset; + __entry->qlen = qlen; + ), + + TP_printk("%s rhp=%p func=%ld %ld", + __entry->rcuname, __entry->rhp, __entry->offset, + __entry->qlen) +); + /* * Tracepoint for marking the beginning rcu_do_batch, performed to start * RCU callback invocation. The first argument is the RCU flavor, @@ -65,50 +356,58 @@ TRACE_EVENT(rcu_batch_start, /* * Tracepoint for the invocation of a single RCU callback function. - * The argument is a pointer to the RCU callback itself. + * The first argument is the type of RCU, and the second argument is + * a pointer to the RCU callback itself. */ TRACE_EVENT(rcu_invoke_callback, - TP_PROTO(struct rcu_head *rhp), + TP_PROTO(char *rcuname, struct rcu_head *rhp), - TP_ARGS(rhp), + TP_ARGS(rcuname, rhp), TP_STRUCT__entry( - __field(void *, rhp) - __field(void *, func) + __field(char *, rcuname) + __field(void *, rhp) + __field(void *, func) ), TP_fast_assign( + __entry->rcuname = rcuname; __entry->rhp = rhp; __entry->func = rhp->func; ), - TP_printk("rhp=%p func=%pf", __entry->rhp, __entry->func) + TP_printk("%s rhp=%p func=%pf", + __entry->rcuname, __entry->rhp, __entry->func) ); /* * Tracepoint for the invocation of a single RCU callback of the special - * kfree() form. The first argument is a pointer to the RCU callback - * and the second argument is the offset of the callback within the - * enclosing RCU-protected data structure. + * kfree() form. The first argument is the RCU flavor, the second + * argument is a pointer to the RCU callback, and the third argument + * is the offset of the callback within the enclosing RCU-protected + * data structure. */ TRACE_EVENT(rcu_invoke_kfree_callback, - TP_PROTO(struct rcu_head *rhp, unsigned long offset), + TP_PROTO(char *rcuname, struct rcu_head *rhp, unsigned long offset), - TP_ARGS(rhp, offset), + TP_ARGS(rcuname, rhp, offset), TP_STRUCT__entry( - __field(void *, rhp) + __field(char *, rcuname) + __field(void *, rhp) __field(unsigned long, offset) ), TP_fast_assign( + __entry->rcuname = rcuname; __entry->rhp = rhp; __entry->offset = offset; ), - TP_printk("rhp=%p func=%ld", __entry->rhp, __entry->offset) + TP_printk("%s rhp=%p func=%ld", + __entry->rcuname, __entry->rhp, __entry->offset) ); /* @@ -136,6 +435,24 @@ TRACE_EVENT(rcu_batch_end, __entry->rcuname, __entry->callbacks_invoked) ); +#else /* #ifdef CONFIG_RCU_TRACE */ + +#define trace_rcu_grace_period(rcuname, gpnum, gpevent) do { } while (0) +#define trace_rcu_grace_period_init(rcuname, gpnum, level, grplo, grphi, qsmask) do { } while (0) +#define trace_rcu_preempt_task(rcuname, pid, gpnum) do { } while (0) +#define trace_rcu_unlock_preempted_task(rcuname, gpnum, pid) do { } while (0) +#define trace_rcu_quiescent_state_report(rcuname, gpnum, mask, qsmask, level, grplo, grphi, gp_tasks) do { } while (0) +#define trace_rcu_fqs(rcuname, gpnum, cpu, qsevent) do { } while (0) +#define trace_rcu_dyntick(polarity) do { } while (0) +#define trace_rcu_callback(rcuname, rhp, qlen) do { } while (0) +#define trace_rcu_kfree_callback(rcuname, rhp, offset, qlen) do { } while (0) +#define trace_rcu_batch_start(rcuname, qlen, blimit) do { } while (0) +#define trace_rcu_invoke_callback(rcuname, rhp) do { } while (0) +#define trace_rcu_invoke_kfree_callback(rcuname, rhp, offset) do { } while (0) +#define trace_rcu_batch_end(rcuname, callbacks_invoked) do { } while (0) + +#endif /* #else #ifdef CONFIG_RCU_TRACE */ + #endif /* _TRACE_RCU_H */ /* This part must be outside protection */ diff --git a/kernel/rcu.h b/kernel/rcu.h index d7f00ec8b47..f600868d550 100644 --- a/kernel/rcu.h +++ b/kernel/rcu.h @@ -69,15 +69,15 @@ static inline void debug_rcu_head_unqueue(struct rcu_head *head) extern void kfree(const void *); -static inline void __rcu_reclaim(struct rcu_head *head) +static inline void __rcu_reclaim(char *rn, struct rcu_head *head) { unsigned long offset = (unsigned long)head->func; if (__is_kfree_rcu_offset(offset)) { - RCU_TRACE(trace_rcu_invoke_kfree_callback(head, offset)); + RCU_TRACE(trace_rcu_invoke_kfree_callback(rn, head, offset)); kfree((void *)head - offset); } else { - RCU_TRACE(trace_rcu_invoke_callback(head)); + RCU_TRACE(trace_rcu_invoke_callback(rn, head)); head->func(head); } } diff --git a/kernel/rcutiny.c b/kernel/rcutiny.c index c9321d86999..da775c87f27 100644 --- a/kernel/rcutiny.c +++ b/kernel/rcutiny.c @@ -147,6 +147,7 @@ void rcu_check_callbacks(int cpu, int user) */ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) { + char *rn = NULL; struct rcu_head *next, *list; unsigned long flags; RCU_TRACE(int cb_count = 0); @@ -171,12 +172,13 @@ static void __rcu_process_callbacks(struct rcu_ctrlblk *rcp) local_irq_restore(flags); /* Invoke the callbacks on the local list. */ + RCU_TRACE(rn = rcp->name); while (list) { next = list->next; prefetch(next); debug_rcu_head_unqueue(list); local_bh_disable(); - __rcu_reclaim(list); + __rcu_reclaim(rn, list); local_bh_enable(); list = next; RCU_TRACE(cb_count++); diff --git a/kernel/rcutree.c b/kernel/rcutree.c index 4e24399cabc..7e0282949f8 100644 --- a/kernel/rcutree.c +++ b/kernel/rcutree.c @@ -166,6 +166,8 @@ void rcu_sched_qs(int cpu) rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); + if (rdp->passed_quiesc == 0) + trace_rcu_grace_period("rcu_sched", rdp->gpnum, "cpuqs"); rdp->passed_quiesc = 1; } @@ -175,6 +177,8 @@ void rcu_bh_qs(int cpu) rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); + if (rdp->passed_quiesc == 0) + trace_rcu_grace_period("rcu_bh", rdp->gpnum, "cpuqs"); rdp->passed_quiesc = 1; } @@ -319,6 +323,7 @@ static int rcu_implicit_offline_qs(struct rcu_data *rdp) * trust its state not to change because interrupts are disabled. */ if (cpu_is_offline(rdp->cpu)) { + trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, "ofl"); rdp->offline_fqs++; return 1; } @@ -359,6 +364,7 @@ void rcu_enter_nohz(void) local_irq_restore(flags); return; } + trace_rcu_dyntick("Start"); /* CPUs seeing atomic_inc() must see prior RCU read-side crit sects */ smp_mb__before_atomic_inc(); /* See above. */ atomic_inc(&rdtp->dynticks); @@ -396,6 +402,7 @@ void rcu_exit_nohz(void) /* CPUs seeing atomic_inc() must see later RCU read-side crit sects */ smp_mb__after_atomic_inc(); /* See above. */ WARN_ON_ONCE(!(atomic_read(&rdtp->dynticks) & 0x1)); + trace_rcu_dyntick("End"); local_irq_restore(flags); } @@ -501,6 +508,7 @@ static int rcu_implicit_dynticks_qs(struct rcu_data *rdp) * of the current RCU grace period. */ if ((curr & 0x1) == 0 || ULONG_CMP_GE(curr, snap + 2)) { + trace_rcu_fqs(rdp->rsp->name, rdp->gpnum, rdp->cpu, "dti"); rdp->dynticks_fqs++; return 1; } @@ -683,6 +691,7 @@ static void __note_new_gpnum(struct rcu_state *rsp, struct rcu_node *rnp, struct * go looking for one. */ rdp->gpnum = rnp->gpnum; + trace_rcu_grace_period(rsp->name, rdp->gpnum, "cpustart"); if (rnp->qsmask & rdp->grpmask) { rdp->qs_pending = 1; rdp->passed_quiesc = 0; @@ -746,6 +755,7 @@ __rcu_process_gp_end(struct rcu_state *rsp, struct rcu_node *rnp, struct rcu_dat /* Remember that we saw this grace-period completion. */ rdp->completed = rnp->completed; + trace_rcu_grace_period(rsp->name, rdp->gpnum, "cpuend"); /* * If we were in an extended quiescent state, we may have @@ -856,6 +866,7 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) /* Advance to a new grace period and initialize state. */ rsp->gpnum++; + trace_rcu_grace_period(rsp->name, rsp->gpnum, "start"); WARN_ON_ONCE(rsp->signaled == RCU_GP_INIT); rsp->signaled = RCU_GP_INIT; /* Hold off force_quiescent_state. */ rsp->jiffies_force_qs = jiffies + RCU_JIFFIES_TILL_FORCE_QS; @@ -870,6 +881,9 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) rsp->signaled = RCU_SIGNAL_INIT; /* force_quiescent_state OK. */ rcu_start_gp_per_cpu(rsp, rnp, rdp); rcu_preempt_boost_start_gp(rnp); + trace_rcu_grace_period_init(rsp->name, rnp->gpnum, + rnp->level, rnp->grplo, + rnp->grphi, rnp->qsmask); raw_spin_unlock_irqrestore(&rnp->lock, flags); return; } @@ -906,6 +920,9 @@ rcu_start_gp(struct rcu_state *rsp, unsigned long flags) if (rnp == rdp->mynode) rcu_start_gp_per_cpu(rsp, rnp, rdp); rcu_preempt_boost_start_gp(rnp); + trace_rcu_grace_period_init(rsp->name, rnp->gpnum, + rnp->level, rnp->grplo, + rnp->grphi, rnp->qsmask); raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ } @@ -939,6 +956,7 @@ static void rcu_report_qs_rsp(struct rcu_state *rsp, unsigned long flags) if (gp_duration > rsp->gp_max) rsp->gp_max = gp_duration; rsp->completed = rsp->gpnum; + trace_rcu_grace_period(rsp->name, rsp->completed, "end"); rsp->signaled = RCU_GP_IDLE; rcu_start_gp(rsp, flags); /* releases root node's rnp->lock. */ } @@ -967,6 +985,10 @@ rcu_report_qs_rnp(unsigned long mask, struct rcu_state *rsp, return; } rnp->qsmask &= ~mask; + trace_rcu_quiescent_state_report(rsp->name, rnp->gpnum, + mask, rnp->qsmask, rnp->level, + rnp->grplo, rnp->grphi, + !!rnp->gp_tasks); if (rnp->qsmask != 0 || rcu_preempt_blocked_readers_cgp(rnp)) { /* Other bits still set at this level, so done. */ @@ -1135,11 +1157,20 @@ static void __rcu_offline_cpu(int cpu, struct rcu_state *rsp) if (rnp->qsmaskinit != 0) { if (rnp != rdp->mynode) raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ + else + trace_rcu_grace_period(rsp->name, + rnp->gpnum + 1 - + !!(rnp->qsmask & mask), + "cpuofl"); break; } - if (rnp == rdp->mynode) + if (rnp == rdp->mynode) { + trace_rcu_grace_period(rsp->name, + rnp->gpnum + 1 - + !!(rnp->qsmask & mask), + "cpuofl"); need_report = rcu_preempt_offline_tasks(rsp, rnp, rdp); - else + } else raw_spin_unlock(&rnp->lock); /* irqs remain disabled. */ mask = rnp->grpmask; rnp = rnp->parent; @@ -1226,7 +1257,7 @@ static void rcu_do_batch(struct rcu_state *rsp, struct rcu_data *rdp) next = list->next; prefetch(next); debug_rcu_head_unqueue(list); - __rcu_reclaim(list); + __rcu_reclaim(rsp->name, list); list = next; if (++count >= bl) break; @@ -1552,6 +1583,12 @@ __call_rcu(struct rcu_head *head, void (*func)(struct rcu_head *rcu), rdp->nxttail[RCU_NEXT_TAIL] = &head->next; rdp->qlen++; + if (__is_kfree_rcu_offset((unsigned long)func)) + trace_rcu_kfree_callback(rsp->name, head, (unsigned long)func, + rdp->qlen); + else + trace_rcu_callback(rsp->name, head, rdp->qlen); + /* If interrupts were disabled, don't dive into RCU core. */ if (irqs_disabled_flags(flags)) { local_irq_restore(flags); @@ -1850,6 +1887,7 @@ rcu_boot_init_percpu_data(int cpu, struct rcu_state *rsp) rdp->dynticks = &per_cpu(rcu_dynticks, cpu); #endif /* #ifdef CONFIG_NO_HZ */ rdp->cpu = cpu; + rdp->rsp = rsp; raw_spin_unlock_irqrestore(&rnp->lock, flags); } @@ -1898,6 +1936,7 @@ rcu_init_percpu_data(int cpu, struct rcu_state *rsp, int preemptible) rdp->gpnum = rnp->completed; /* if GP in progress... */ rdp->completed = rnp->completed; rdp->passed_quiesc_completed = rnp->completed - 1; + trace_rcu_grace_period(rsp->name, rdp->gpnum, "cpuonl"); } raw_spin_unlock(&rnp->lock); /* irqs already disabled. */ rnp = rnp->parent; diff --git a/kernel/rcutree.h b/kernel/rcutree.h index eee6c9406b4..d11a0065321 100644 --- a/kernel/rcutree.h +++ b/kernel/rcutree.h @@ -299,6 +299,7 @@ struct rcu_data { unsigned long n_rp_need_nothing; int cpu; + struct rcu_state *rsp; }; /* Values for signaled field in struct rcu_state. */ diff --git a/kernel/rcutree_plugin.h b/kernel/rcutree_plugin.h index 94d9ca1e406..bdb2e82f78d 100644 --- a/kernel/rcutree_plugin.h +++ b/kernel/rcutree_plugin.h @@ -124,6 +124,8 @@ static void rcu_preempt_qs(int cpu) rdp->passed_quiesc_completed = rdp->gpnum - 1; barrier(); + if (rdp->passed_quiesc == 0) + trace_rcu_grace_period("rcu_preempt", rdp->gpnum, "cpuqs"); rdp->passed_quiesc = 1; current->rcu_read_unlock_special &= ~RCU_READ_UNLOCK_NEED_QS; } @@ -190,6 +192,11 @@ static void rcu_preempt_note_context_switch(int cpu) if (rnp->qsmask & rdp->grpmask) rnp->gp_tasks = &t->rcu_node_entry; } + trace_rcu_preempt_task(rdp->rsp->name, + t->pid, + (rnp->qsmask & rdp->grpmask) + ? rnp->gpnum + : rnp->gpnum + 1); raw_spin_unlock_irqrestore(&rnp->lock, flags); } else if (t->rcu_read_lock_nesting < 0 && t->rcu_read_unlock_special) { @@ -344,6 +351,8 @@ static noinline void rcu_read_unlock_special(struct task_struct *t) smp_mb(); /* ensure expedited fastpath sees end of RCU c-s. */ np = rcu_next_node_entry(t, rnp); list_del_init(&t->rcu_node_entry); + trace_rcu_unlock_preempted_task("rcu_preempt", + rnp->gpnum, t->pid); if (&t->rcu_node_entry == rnp->gp_tasks) rnp->gp_tasks = np; if (&t->rcu_node_entry == rnp->exp_tasks) @@ -364,10 +373,17 @@ static noinline void rcu_read_unlock_special(struct task_struct *t) * we aren't waiting on any CPUs, report the quiescent state. * Note that rcu_report_unblock_qs_rnp() releases rnp->lock. */ - if (empty) - raw_spin_unlock_irqrestore(&rnp->lock, flags); - else + if (!empty && !rcu_preempt_blocked_readers_cgp(rnp)) { + trace_rcu_quiescent_state_report("preempt_rcu", + rnp->gpnum, + 0, rnp->qsmask, + rnp->level, + rnp->grplo, + rnp->grphi, + !!rnp->gp_tasks); rcu_report_unblock_qs_rnp(rnp, flags); + } else + raw_spin_unlock_irqrestore(&rnp->lock, flags); #ifdef CONFIG_RCU_BOOST /* Unboost if we were boosted. */ |