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authorRickard Green <[email protected]>2019-01-10 16:45:14 +0100
committerRickard Green <[email protected]>2019-01-11 15:41:39 +0100
commiteaaecd5aeba890a012ede00d76e60e994926f4a6 (patch)
tree05140428724bef98e36e327815adec1407da26e7 /erts
parentdb6059a9217767a6e42e93cec05089c0ec977d20 (diff)
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Fix bug causing dirty scheduler sleeper list inconsistency
Diffstat (limited to 'erts')
-rw-r--r--erts/emulator/beam/erl_process.c176
-rw-r--r--erts/emulator/beam/erl_process.h2
2 files changed, 119 insertions, 59 deletions
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 9f6adb03d0..0090a7f69c 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -88,10 +88,6 @@
#undef HARDDEBUG
#endif
-#ifdef HARDDEBUG
-#define HARDDEBUG_RUNQS
-#endif
-
#ifdef HIPE
#include "hipe_mode_switch.h" /* for hipe_init_process() */
#include "hipe_signal.h" /* for hipe_thread_signal_init() */
@@ -3420,6 +3416,46 @@ static void suspend_scheduler(ErtsSchedulerData *esdp);
#endif /* ERTS_SMP */
+#ifdef HARDDEBUG
+#define ERTS_HDBG_CHK_SLEEP_LIST(SL, L, F, FN) \
+ check_sleepers_list((SL), (L), (F), (FN))
+static void check_sleepers_list(ErtsSchedulerSleepList *sl,
+ int lock,
+ ErtsSchedulerSleepInfo *find,
+ ErtsSchedulerSleepInfo *find_not)
+{
+ ErtsSchedulerSleepInfo *last_out;
+ int found = 0;
+
+ if (lock)
+ erts_smp_spin_lock(&sl->lock);
+
+ ERTS_ASSERT(!find_not || (!find_not->next && !find_not->prev));
+
+ last_out = sl->list;
+ if (last_out) {
+ ErtsSchedulerSleepInfo *tmp = last_out;
+ do {
+ ERTS_ASSERT(tmp->next);
+ ERTS_ASSERT(tmp->prev);
+ ERTS_ASSERT(tmp->next->prev == tmp);
+ ERTS_ASSERT(tmp->prev->next == tmp);
+ ERTS_ASSERT(tmp != find_not);
+ if (tmp == find)
+ found = !0;
+ tmp = tmp->next;
+
+ } while (tmp != last_out);
+ }
+ ERTS_ASSERT(!find || found);
+
+ if (lock)
+ erts_smp_spin_unlock(&sl->lock);
+}
+#else
+#define ERTS_HDBG_CHK_SLEEP_LIST(SL, L, F, FN) ((void) 0)
+#endif
+
static void
scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
{
@@ -3436,32 +3472,12 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
ERTS_SMP_LC_ASSERT(erts_smp_lc_runq_is_locked(rq));
-#ifdef ERTS_DIRTY_SCHEDULERS
- if (ERTS_RUNQ_IX_IS_DIRTY(rq->ix))
- erts_smp_spin_lock(&rq->sleepers.lock);
-#endif
flgs = sched_prep_spin_wait(ssi);
if (flgs & ERTS_SSI_FLG_SUSPENDED) {
/* Go suspend instead... */
-#ifdef ERTS_DIRTY_SCHEDULERS
- if (ERTS_RUNQ_IX_IS_DIRTY(rq->ix))
- erts_smp_spin_unlock(&rq->sleepers.lock);
-#endif
return;
}
-#ifdef ERTS_DIRTY_SCHEDULERS
- if (ERTS_RUNQ_IX_IS_DIRTY(rq->ix)) {
- ssi->prev = NULL;
- ssi->next = rq->sleepers.list;
- if (rq->sleepers.list)
- rq->sleepers.list->prev = ssi;
- rq->sleepers.list = ssi;
- erts_smp_spin_unlock(&rq->sleepers.lock);
- dirty_active(esdp, -1);
- }
-#endif
-
/*
* If all schedulers are waiting, one of them *should*
* be waiting in erl_sys_schedule()
@@ -3471,6 +3487,28 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
sched_waiting(esdp->no, rq);
+#ifdef ERTS_DIRTY_SCHEDULERS
+ if (ERTS_RUNQ_IX_IS_DIRTY(rq->ix)) {
+ erts_smp_spin_lock(&rq->sleepers.lock);
+ ERTS_HDBG_CHK_SLEEP_LIST(&rq->sleepers, 0, NULL, ssi);
+ ASSERT(!ssi->next); /* Not in sleepers list */
+ ASSERT(!ssi->prev);
+ if (!rq->sleepers.list) {
+ ssi->next = ssi->prev = ssi;
+ rq->sleepers.list = ssi;
+ }
+ else {
+ ssi->prev = rq->sleepers.list;
+ ssi->next = rq->sleepers.list->next;
+ ssi->prev->next = ssi;
+ ssi->next->prev = ssi;
+ }
+ ERTS_HDBG_CHK_SLEEP_LIST(&rq->sleepers, 0, ssi, NULL);
+ erts_smp_spin_unlock(&rq->sleepers.lock);
+ dirty_active(esdp, -1);
+ }
+#endif
+
erts_smp_runq_unlock(rq);
spincount = sched_busy_wait.tse;
@@ -3597,7 +3635,31 @@ scheduler_wait(int *fcalls, ErtsSchedulerData *esdp, ErtsRunQueue *rq)
erts_thr_progress_active(esdp, thr_prgr_active = 1);
sched_wall_time_change(esdp, 1);
}
-
+
+#ifdef ERTS_DIRTY_SCHEDULERS
+ if (ERTS_RUNQ_IX_IS_DIRTY(rq->ix)) {
+ erts_smp_spin_lock(&rq->sleepers.lock);
+ ERTS_HDBG_CHK_SLEEP_LIST(&rq->sleepers, 0, ssi->next ? ssi : NULL, NULL);
+ if (ssi->next) { /* Still in list... */
+ if (ssi->next == ssi) {
+ ASSERT(rq->sleepers.list == ssi);
+ ASSERT(ssi->prev == ssi);
+ rq->sleepers.list = NULL;
+ }
+ else {
+ ASSERT(ssi->prev != ssi);
+ if (rq->sleepers.list == ssi)
+ rq->sleepers.list = ssi->next;
+ ssi->prev->next = ssi->next;
+ ssi->next->prev = ssi->prev;
+ }
+ ssi->next = ssi->prev = NULL;
+ }
+ ERTS_HDBG_CHK_SLEEP_LIST(&rq->sleepers, 0, NULL, ssi);
+ erts_smp_spin_unlock(&rq->sleepers.lock);
+ }
+#endif
+
erts_smp_runq_lock(rq);
sched_active(esdp->no, rq);
@@ -3883,55 +3945,44 @@ wake_scheduler(ErtsRunQueue *rq)
#ifdef ERTS_DIRTY_SCHEDULERS
static void
-wake_dirty_schedulers(ErtsRunQueue *rq, int one)
+wake_dirty_scheduler(ErtsRunQueue *rq)
{
- ErtsSchedulerSleepInfo *ssi;
+ ErtsSchedulerSleepInfo *lo_ssi, *fo_ssi;
ErtsSchedulerSleepList *sl;
ASSERT(ERTS_RUNQ_IX_IS_DIRTY(rq->ix));
sl = &rq->sleepers;
erts_smp_spin_lock(&sl->lock);
- ssi = sl->list;
- if (!ssi) {
+ ERTS_HDBG_CHK_SLEEP_LIST(&rq->sleepers, 0, NULL, NULL);
+ lo_ssi = sl->list;
+ if (!lo_ssi) {
erts_smp_spin_unlock(&sl->lock);
- if (one)
- wake_scheduler(rq);
- } else if (one) {
+ wake_scheduler(rq);
+ }
+ else {
erts_aint32_t flgs;
- if (ssi->prev)
- ssi->prev->next = ssi->next;
- else {
- ASSERT(sl->list == ssi);
- sl->list = ssi->next;
+ fo_ssi = lo_ssi->next;
+ ASSERT(fo_ssi->prev == lo_ssi);
+ if (fo_ssi == lo_ssi) {
+ ASSERT(lo_ssi->prev == lo_ssi);
+ sl->list = NULL;
+ }
+ else {
+ ASSERT(lo_ssi->prev != lo_ssi);
+ lo_ssi->next = fo_ssi->next;
+ fo_ssi->next->prev = fo_ssi->prev;
}
- if (ssi->next)
- ssi->next->prev = ssi->prev;
-
- erts_smp_spin_unlock(&sl->lock);
-
- ERTS_THR_MEMORY_BARRIER;
- flgs = ssi_flags_set_wake(ssi);
- erts_sched_finish_poke(ssi, flgs);
- } else {
- sl->list = NULL;
+ fo_ssi->next = fo_ssi->prev = NULL;
+ ERTS_HDBG_CHK_SLEEP_LIST(&rq->sleepers, 0, NULL, fo_ssi);
erts_smp_spin_unlock(&sl->lock);
ERTS_THR_MEMORY_BARRIER;
- do {
- ErtsSchedulerSleepInfo *wake_ssi = ssi;
- ssi = ssi->next;
- erts_sched_finish_poke(wake_ssi, ssi_flags_set_wake(wake_ssi));
- } while (ssi);
+ flgs = ssi_flags_set_wake(fo_ssi);
+ erts_sched_finish_poke(fo_ssi, flgs);
}
}
-static void
-wake_dirty_scheduler(ErtsRunQueue *rq)
-{
- wake_dirty_schedulers(rq, 1);
-}
-
#endif
#define ERTS_NO_USED_RUNQS_SHIFT 16
@@ -6371,6 +6422,8 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online
for (ix = 0; ix < no_dirty_cpu_schedulers; ix++) {
ErtsSchedulerSleepInfo *ssi = &aligned_dirty_cpu_sched_sleep_info[ix].ssi;
erts_smp_atomic32_init_nob(&ssi->flags, 0);
+ ssi->next = NULL;
+ ssi->prev = NULL;
ssi->event = NULL; /* initialized in sched_dirty_cpu_thread_func */
erts_atomic32_init_nob(&ssi->aux_work, 0);
}
@@ -6381,6 +6434,8 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online
for (ix = 0; ix < no_dirty_io_schedulers; ix++) {
ErtsSchedulerSleepInfo *ssi = &aligned_dirty_io_sched_sleep_info[ix].ssi;
erts_smp_atomic32_init_nob(&ssi->flags, 0);
+ ssi->next = NULL;
+ ssi->prev = NULL;
ssi->event = NULL; /* initialized in sched_dirty_io_thread_func */
erts_atomic32_init_nob(&ssi->aux_work, 0);
}
@@ -7895,6 +7950,11 @@ suspend_scheduler(ErtsSchedulerData *esdp)
return;
}
+#ifdef HARDDEBUG
+ if (sched_type != ERTS_SCHED_NORMAL)
+ ERTS_HDBG_CHK_SLEEP_LIST(&esdp->run_queue->sleepers, !0, NULL, ssi);
+#endif
+
if (erts_smp_atomic32_read_nob(&ssi->flags) & ERTS_SSI_FLG_MSB_EXEC) {
ASSERT(no == 1);
if (!msb_scheduler_type_switch(sched_type, esdp, no))
diff --git a/erts/emulator/beam/erl_process.h b/erts/emulator/beam/erl_process.h
index 5cac939771..b3385b780f 100644
--- a/erts/emulator/beam/erl_process.h
+++ b/erts/emulator/beam/erl_process.h
@@ -368,7 +368,7 @@ typedef struct ErtsSchedulerSleepInfo_ ErtsSchedulerSleepInfo;
#ifdef ERTS_DIRTY_SCHEDULERS
typedef struct {
erts_smp_spinlock_t lock;
- ErtsSchedulerSleepInfo *list;
+ ErtsSchedulerSleepInfo *list; /* circular lifo list; points to last out */
} ErtsSchedulerSleepList;
#endif