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-rw-r--r--erts/emulator/beam/erl_process.c192
1 files changed, 158 insertions, 34 deletions
diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index b7499c5b5a..e4584e7cc2 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -959,10 +959,24 @@ typedef struct {
erts_smp_atomic32_t refc;
} ErtsSchedWallTimeReq;
+typedef struct {
+ Process *proc;
+ Eterm ref;
+ Eterm ref_heap[REF_THING_SIZE];
+ Uint req_sched;
+ erts_smp_atomic32_t refc;
+} ErtsSystemCheckReq;
+
+
ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(swtreq,
- ErtsSchedWallTimeReq,
- 5,
- ERTS_ALC_T_SCHED_WTIME_REQ)
+ ErtsSchedWallTimeReq,
+ 5,
+ ERTS_ALC_T_SCHED_WTIME_REQ)
+
+ERTS_SCHED_PREF_QUICK_ALLOC_IMPL(screq,
+ ErtsSystemCheckReq,
+ 5,
+ ERTS_ALC_T_SYS_CHECK_REQ)
static void
reply_sched_wall_time(void *vswtrp)
@@ -1095,6 +1109,75 @@ erts_sched_wall_time_request(Process *c_p, int set, int enable)
return ref;
}
+static void
+reply_system_check(void *vscrp)
+{
+ ErtsSchedulerData *esdp = erts_get_scheduler_data();
+ ErtsSystemCheckReq *scrp = (ErtsSystemCheckReq *) vscrp;
+ ErtsProcLocks rp_locks = (scrp->req_sched == esdp->no ? ERTS_PROC_LOCK_MAIN : 0);
+ Process *rp = scrp->proc;
+ Eterm msg;
+ Eterm *hp = NULL;
+ Eterm **hpp;
+ Uint sz;
+ ErlOffHeap *ohp = NULL;
+ ErtsMessage *mp = NULL;
+
+ ASSERT(esdp);
+#ifdef ERTS_DIRTY_SCHEDULERS
+ ASSERT(!ERTS_SCHEDULER_IS_DIRTY(esdp));
+#endif
+
+ sz = REF_THING_SIZE;
+ mp = erts_alloc_message_heap(rp, &rp_locks, sz, &hp, &ohp);
+ hpp = &hp;
+ msg = STORE_NC(hpp, ohp, scrp->ref);
+
+ erts_queue_message(rp, &rp_locks, mp, msg, NIL);
+
+ if (scrp->req_sched == esdp->no)
+ rp_locks &= ~ERTS_PROC_LOCK_MAIN;
+
+ if (rp_locks)
+ erts_smp_proc_unlock(rp, rp_locks);
+
+ erts_proc_dec_refc(rp);
+
+ if (erts_smp_atomic32_dec_read_nob(&scrp->refc) == 0)
+ screq_free(vscrp);
+}
+
+
+Eterm erts_system_check_request(Process *c_p) {
+ ErtsSchedulerData *esdp = ERTS_PROC_GET_SCHDATA(c_p);
+ Eterm ref;
+ ErtsSystemCheckReq *scrp;
+ Eterm *hp;
+
+ scrp = screq_alloc();
+ ref = erts_make_ref(c_p);
+ hp = &scrp->ref_heap[0];
+
+ scrp->proc = c_p;
+ scrp->ref = STORE_NC(&hp, NULL, ref);
+ scrp->req_sched = esdp->no;
+ erts_smp_atomic32_init_nob(&scrp->refc, (erts_aint32_t) erts_no_schedulers);
+
+ erts_proc_add_refc(c_p, (Sint) erts_no_schedulers);
+
+#ifdef ERTS_SMP
+ if (erts_no_schedulers > 1)
+ erts_schedule_multi_misc_aux_work(1,
+ erts_no_schedulers,
+ reply_system_check,
+ (void *) scrp);
+#endif
+
+ reply_system_check((void *) scrp);
+
+ return ref;
+}
+
static ERTS_INLINE ErtsProcList *
proclist_create(Process *p)
{
@@ -5775,6 +5858,7 @@ erts_init_scheduling(int no_schedulers, int no_schedulers_online
init_misc_aux_work();
init_swtreq_alloc();
+ init_screq_alloc();
erts_atomic32_init_nob(&debug_wait_completed_count, 0); /* debug only */
debug_wait_completed_flags = 0;
@@ -6577,9 +6661,6 @@ suspend_process(Process *c_p, Process *p)
if (suspended) {
- ASSERT(!(ERTS_PSFLG_RUNNING & state)
- || p == erts_get_current_process());
-
if (suspended > 0 && erts_system_profile_flags.runnable_procs) {
/* 'state' is before our change... */
@@ -8514,9 +8595,8 @@ pid2proc_not_running(Process *c_p, ErtsProcLocks c_p_locks,
resume_process(rp, rp_locks);
}
else {
-
rp = erts_pid2proc(c_p, c_p_locks|ERTS_PROC_LOCK_STATUS,
- pid, pid_locks|ERTS_PROC_LOCK_STATUS);
+ pid, ERTS_PROC_LOCK_STATUS);
if (!rp) {
c_p->flags &= ~F_P2PNR_RESCHED;
@@ -8525,40 +8605,84 @@ pid2proc_not_running(Process *c_p, ErtsProcLocks c_p_locks,
ASSERT(!(c_p->flags & F_P2PNR_RESCHED));
- if (suspend) {
- if (suspend_process(c_p, rp))
- goto done;
- }
- else {
- if (!((ERTS_PSFLG_RUNNING|ERTS_PSFLG_RUNNING_SYS)
- & erts_smp_atomic32_read_acqb(&rp->state)))
- goto done;
+ /*
+ * Suspend the other process in order to prevent
+ * it from being selected for normal execution.
+ * This will however not prevent it from being
+ * selected for execution of a system task. If
+ * it is selected for execution of a system task
+ * we might be blocked for quite a while if the
+ * try-lock below fails. That is, there is room
+ * for improvement here...
+ */
- }
+ if (!suspend_process(c_p, rp)) {
+ /* Other process running */
- /* Other process running */
+ ASSERT(ERTS_PSFLG_RUNNING
+ & erts_smp_atomic32_read_nob(&rp->state));
- /*
- * If we got pending suspenders and suspend ourselves waiting
- * to suspend another process we might deadlock.
- * In this case we have to yield, be suspended by
- * someone else and then do it all over again.
- */
- if (!c_p->pending_suspenders) {
- /* Mark rp pending for suspend by c_p */
- add_pend_suspend(rp, c_p->common.id, handle_pend_sync_suspend);
- ASSERT(is_nil(c_p->suspendee));
+ running:
- /* Suspend c_p; when rp is suspended c_p will be resumed. */
- suspend_process(c_p, c_p);
- c_p->flags |= F_P2PNR_RESCHED;
+ /*
+ * If we got pending suspenders and suspend ourselves waiting
+ * to suspend another process we might deadlock.
+ * In this case we have to yield, be suspended by
+ * someone else and then do it all over again.
+ */
+ if (!c_p->pending_suspenders) {
+ /* Mark rp pending for suspend by c_p */
+ add_pend_suspend(rp, c_p->common.id, handle_pend_sync_suspend);
+ ASSERT(is_nil(c_p->suspendee));
+
+ /* Suspend c_p; when rp is suspended c_p will be resumed. */
+ suspend_process(c_p, c_p);
+ c_p->flags |= F_P2PNR_RESCHED;
+ }
+ /* Yield (caller is assumed to yield immediately in bif). */
+ erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
+ rp = ERTS_PROC_LOCK_BUSY;
+ }
+ else {
+ ErtsProcLocks need_locks = pid_locks & ~ERTS_PROC_LOCK_STATUS;
+ if (need_locks && erts_smp_proc_trylock(rp, need_locks) == EBUSY) {
+ if (ERTS_PSFLG_RUNNING_SYS
+ & erts_smp_atomic32_read_nob(&rp->state)) {
+ /* Executing system task... */
+ resume_process(rp, ERTS_PROC_LOCK_STATUS);
+ goto running;
+ }
+ erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
+ /*
+ * If we are unlucky, the process just got selected for
+ * execution of a system task. In this case we may be
+ * blocked here for quite a while... Execution of system
+ * tasks are fortunately quite rare events. We try to
+ * avoid this by checking if it is in a state executing
+ * system tasks (above), but it will not prevent all
+ * scenarios for a long block here...
+ */
+ rp = erts_pid2proc(c_p, c_p_locks|ERTS_PROC_LOCK_STATUS,
+ pid, pid_locks|ERTS_PROC_LOCK_STATUS);
+ if (!rp)
+ goto done;
+ }
+
+ /*
+ * The previous suspend has prevented the process
+ * from being selected for normal execution regardless
+ * of locks held or not held on it...
+ */
+ ASSERT(!(ERTS_PSFLG_RUNNING
+ & erts_smp_atomic32_read_nob(&rp->state)));
+
+ if (!suspend)
+ resume_process(rp, pid_locks|ERTS_PROC_LOCK_STATUS);
}
- /* Yield (caller is assumed to yield immediately in bif). */
- erts_smp_proc_unlock(rp, pid_locks|ERTS_PROC_LOCK_STATUS);
- rp = ERTS_PROC_LOCK_BUSY;
}
done:
+
if (rp && rp != ERTS_PROC_LOCK_BUSY && !(pid_locks & ERTS_PROC_LOCK_STATUS))
erts_smp_proc_unlock(rp, ERTS_PROC_LOCK_STATUS);
if (unlock_c_p_status)
generated by cgit v1.2.3 (git 2.25.1) at 2024-07-24 13:11:43 +0000