3 files changed, 36 insertions, 1 deletions
diff --git a/src/core/ext/lb_policy/pick_first/pick_first.c b/src/core/ext/lb_policy/pick_first/pick_first.c
index 5926f9d70b..0d215cd196 100644
--- a/src/core/ext/lb_policy/pick_first/pick_first.c
+++ b/src/core/ext/lb_policy/pick_first/pick_first.c
@@ -109,7 +109,7 @@ static void pf_shutdown(grpc_exec_ctx *exec_ctx, grpc_lb_policy *pol) {
   if (selected != NULL) {
     grpc_connected_subchannel_notify_on_state_change(
         exec_ctx, selected, NULL, NULL, &p->connectivity_changed);
-  } else {
+  } else if (p->num_subchannels > 0) {
     grpc_subchannel_notify_on_state_change(
         exec_ctx, p->subchannels[p->checking_subchannel], NULL, NULL,
         &p->connectivity_changed);
diff --git a/src/core/lib/support/log.c b/src/core/lib/support/log.c
index 04156a5b1f..882abf673c 100644
--- a/src/core/lib/support/log.c
+++ b/src/core/lib/support/log.c
@@ -31,14 +31,20 @@
  *
  */
 
+#include <grpc/support/alloc.h>
+#include <grpc/support/atm.h>
 #include <grpc/support/log.h>
 #include <grpc/support/port_platform.h>
 
+#include "src/core/lib/support/env.h"
+#include "src/core/lib/support/string.h"
+
 #include <stdio.h>
 #include <string.h>
 
 extern void gpr_default_log(gpr_log_func_args *args);
 static gpr_log_func g_log_func = gpr_default_log;
+static gpr_atm g_min_severity_to_print = GPR_LOG_VERBOSITY_UNSET;
 
 const char *gpr_log_severity_string(gpr_log_severity severity) {
   switch (severity) {
@@ -54,6 +60,9 @@ const char *gpr_log_severity_string(gpr_log_severity severity) {
 
 void gpr_log_message(const char *file, int line, gpr_log_severity severity,
                      const char *message) {
+  if ((gpr_atm)severity < gpr_atm_no_barrier_load(&g_min_severity_to_print))
+    return;
+
   gpr_log_func_args lfargs;
   memset(&lfargs, 0, sizeof(lfargs));
   lfargs.file = file;
@@ -63,4 +72,28 @@ void gpr_log_message(const char *file, int line, gpr_log_severity severity,
   g_log_func(&lfargs);
 }
 
+void gpr_set_log_verbosity(gpr_log_severity min_severity_to_print) {
+  gpr_atm_no_barrier_store(&g_min_severity_to_print,
+                           (gpr_atm)min_severity_to_print);
+}
+
+void gpr_log_verbosity_init() {
+  char *verbosity = gpr_getenv("GRPC_VERBOSITY");
+  if (verbosity == NULL) return;
+
+  gpr_atm min_severity_to_print = GPR_LOG_VERBOSITY_UNSET;
+  if (strcmp(verbosity, "DEBUG") == 0) {
+    min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_DEBUG;
+  } else if (strcmp(verbosity, "INFO") == 0) {
+    min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_INFO;
+  } else if (strcmp(verbosity, "ERROR") == 0) {
+    min_severity_to_print = (gpr_atm)GPR_LOG_SEVERITY_ERROR;
+  }
+  gpr_free(verbosity);
+  if ((gpr_atm_no_barrier_load(&g_min_severity_to_print)) ==
+      GPR_LOG_VERBOSITY_UNSET) {
+    gpr_atm_no_barrier_store(&g_min_severity_to_print, min_severity_to_print);
+  }
+}
+
 void gpr_set_log_function(gpr_log_func f) { g_log_func = f; }
diff --git a/src/core/lib/surface/init.c b/src/core/lib/surface/init.c
index ec75af6e06..d4eb2f8ddd 100644
--- a/src/core/lib/surface/init.c
+++ b/src/core/lib/surface/init.c
@@ -38,6 +38,7 @@
 
 #include <grpc/grpc.h>
 #include <grpc/support/alloc.h>
+#include <grpc/support/log.h>
 #include <grpc/support/time.h>
 #include "src/core/lib/channel/channel_stack.h"
 #include "src/core/lib/channel/compress_filter.h"
@@ -69,6 +70,7 @@ static gpr_mu g_init_mu;
 static int g_initializations;
 
 static void do_basic_init(void) {
+  gpr_log_verbosity_init();
   gpr_mu_init(&g_init_mu);
   grpc_register_built_in_plugins();
   g_initializations = 0;