Don't go to single-scheduler mode when managing breakpoints

Calls to erlang:set_trace_pattern/3 will no longer block all
other schedulers.

We will still go to single-scheduler mode when new code is loaded
for a module that is traced, or when loading code when there is a
default trace pattern set. That is not impossible to fix, but that
requires much closer cooperation between tracing BIFs and the loader
BIFs.

1 files changed, 55 insertions, 0 deletions

diff --git a/erts/emulator/beam/erl_process.c b/erts/emulator/beam/erl_process.c
index 3d978f4994..e07c9ae2b0 100644
--- a/erts/emulator/beam/erl_process.c
+++ b/erts/emulator/beam/erl_process.c
@@ -530,6 +530,7 @@ dbg_chk_aux_work_val(erts_aint32_t value)
 #endif
 #ifdef ERTS_SMP
     valid |= ERTS_SSI_AUX_WORK_CODE_IX_ACTIVATION;
+    valid |= ERTS_SSI_AUX_WORK_FINISH_BP;
 #endif
 #ifdef ERTS_SSI_AUX_WORK_REAP_PORTS
     valid |= ERTS_SSI_AUX_WORK_REAP_PORTS;
@@ -1446,6 +1447,55 @@ handle_code_ix_activation(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 }
 #endif /* ERTS_SMP */
 
+#ifdef ERTS_SMP
+void
+erts_notify_finish_breakpointing(Process* p)
+{
+    ErtsAuxWorkData* awdp = &p->scheduler_data->aux_work_data;
+
+    ASSERT(awdp->bp_ix_activation.stager == NULL);
+    awdp->bp_ix_activation.stager = p;
+    awdp->bp_ix_activation.thr_prgr = erts_thr_progress_later(awdp->esdp);
+    erts_thr_progress_wakeup(awdp->esdp, awdp->bp_ix_activation.thr_prgr);
+    erts_smp_proc_inc_refc(p);
+    set_aux_work_flags_wakeup_relb(p->scheduler_data->ssi,
+				   ERTS_SSI_AUX_WORK_FINISH_BP);
+}
+
+static erts_aint32_t
+handle_finish_bp(ErtsAuxWorkData* awdp, erts_aint32_t aux_work)
+{
+    ErtsThrPrgrVal current = haw_thr_prgr_current(awdp);
+
+    if (!erts_thr_progress_has_reached_this(current,
+					    awdp->bp_ix_activation.thr_prgr)) {
+	return aux_work & ~ERTS_SSI_AUX_WORK_FINISH_BP;
+    }
+    if (erts_finish_breakpointing()) { /* Not done */
+	/* Arrange for being called again */
+	awdp->bp_ix_activation.thr_prgr =
+	    erts_thr_progress_later(awdp->esdp);
+	erts_thr_progress_wakeup(awdp->esdp, awdp->bp_ix_activation.thr_prgr);
+    } else {			/* Done */
+	Process* p;
+
+	unset_aux_work_flags(awdp->ssi, ERTS_SSI_AUX_WORK_FINISH_BP);
+	p = awdp->bp_ix_activation.stager;
+#ifdef DEBUG
+	awdp->bp_ix_activation.stager = NULL;
+#endif
+	erts_smp_proc_lock(p, ERTS_PROC_LOCK_STATUS);
+	if (!ERTS_PROC_IS_EXITING(p)) {
+	    erts_resume(p, ERTS_PROC_LOCK_STATUS);
+	}
+	erts_smp_proc_unlock(p, ERTS_PROC_LOCK_STATUS);
+	erts_smp_proc_dec_refc(p);
+	erts_release_code_write_permission();
+    }
+    return aux_work & ~ERTS_SSI_AUX_WORK_FINISH_BP;
+}
+#endif /* ERTS_SMP */
+
 static ERTS_INLINE erts_aint32_t
 handle_fix_alloc(ErtsAuxWorkData *awdp, erts_aint32_t aux_work)
 {
@@ -1817,6 +1867,11 @@ handle_aux_work(ErtsAuxWorkData *awdp, erts_aint32_t orig_aux_work, int waiting)
     HANDLE_AUX_WORK(ERTS_SSI_AUX_WORK_REAP_PORTS,
 		    handle_reap_ports);
 
+#ifdef ERTS_SMP
+    HANDLE_AUX_WORK(ERTS_SSI_AUX_WORK_FINISH_BP,
+		    handle_finish_bp);
+#endif
+
     ERTS_DBG_CHK_AUX_WORK_VAL(aux_work);
 
 #ifdef ERTS_SMP