Merge github.com:grpc/grpc into trim-the-locks

17 files changed, 472 insertions, 184 deletions

diff --git a/src/core/lib/http/parser.c b/src/core/lib/http/parser.c
index 2f84adc187..b9c56c103c 100644
--- a/src/core/lib/http/parser.c
+++ b/src/core/lib/http/parser.c
@@ -284,9 +284,9 @@ static grpc_error *addbyte(grpc_http_parser *parser, uint8_t byte,
     case GRPC_HTTP_HEADERS:
       if (parser->cur_line_length >= GRPC_HTTP_PARSER_MAX_HEADER_LENGTH) {
         if (grpc_http1_trace)
-          gpr_log(GPR_ERROR, "HTTP client max line length (%d) exceeded",
+          gpr_log(GPR_ERROR, "HTTP header max line length (%d) exceeded",
                   GRPC_HTTP_PARSER_MAX_HEADER_LENGTH);
-        return GRPC_ERROR_NONE;
+        return GRPC_ERROR_CREATE("HTTP header max line length exceeded");
       }
       parser->cur_line[parser->cur_line_length] = byte;
       parser->cur_line_length++;
diff --git a/src/core/lib/iomgr/error.c b/src/core/lib/iomgr/error.c
index dbe5b139f9..7cdbe30198 100644
--- a/src/core/lib/iomgr/error.c
+++ b/src/core/lib/iomgr/error.c
@@ -35,6 +35,7 @@
 
 #include <string.h>
 
+#include <grpc/slice.h>
 #include <grpc/status.h>
 #include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
@@ -47,46 +48,7 @@
 
 #include "src/core/lib/iomgr/error_internal.h"
 #include "src/core/lib/profiling/timers.h"
-
-static void destroy_integer(void *key) {}
-
-static void *copy_integer(void *key) { return key; }
-
-static long compare_integers(void *key1, void *key2) {
-  return GPR_ICMP((uintptr_t)key1, (uintptr_t)key2);
-}
-
-static void destroy_string(void *str) { gpr_free(str); }
-
-static void *copy_string(void *str) { return gpr_strdup(str); }
-
-static void destroy_err(void *err) { GRPC_ERROR_UNREF(err); }
-
-static void *copy_err(void *err) { return GRPC_ERROR_REF(err); }
-
-static void destroy_time(void *tm) { gpr_free(tm); }
-
-static gpr_timespec *box_time(gpr_timespec tm) {
-  gpr_timespec *out = gpr_malloc(sizeof(*out));
-  *out = tm;
-  return out;
-}
-
-static void *copy_time(void *tm) { return box_time(*(gpr_timespec *)tm); }
-
-static const gpr_avl_vtable avl_vtable_ints = {destroy_integer, copy_integer,
-                                               compare_integers,
-                                               destroy_integer, copy_integer};
-
-static const gpr_avl_vtable avl_vtable_strs = {destroy_integer, copy_integer,
-                                               compare_integers, destroy_string,
-                                               copy_string};
-
-static const gpr_avl_vtable avl_vtable_times = {
-    destroy_integer, copy_integer, compare_integers, destroy_time, copy_time};
-
-static const gpr_avl_vtable avl_vtable_errs = {
-    destroy_integer, copy_integer, compare_integers, destroy_err, copy_err};
+#include "src/core/lib/slice/slice_internal.h"
 
 static const char *error_int_name(grpc_error_ints key) {
   switch (key) {
@@ -120,6 +82,8 @@ static const char *error_int_name(grpc_error_ints key) {
       return "limit";
     case GRPC_ERROR_INT_OCCURRED_DURING_WRITE:
       return "occurred_during_write";
+    case GRPC_ERROR_INT_MAX:
+      GPR_UNREACHABLE_CODE(return "unknown");
   }
   GPR_UNREACHABLE_CODE(return "unknown");
 }
@@ -150,6 +114,8 @@ static const char *error_str_name(grpc_error_strs key) {
       return "filename";
     case GRPC_ERROR_STR_QUEUED_BUFFERS:
       return "queued_buffers";
+    case GRPC_ERROR_STR_MAX:
+      GPR_UNREACHABLE_CODE(return "unknown");
   }
   GPR_UNREACHABLE_CODE(return "unknown");
 }
@@ -158,6 +124,8 @@ static const char *error_time_name(grpc_error_times key) {
   switch (key) {
     case GRPC_ERROR_TIME_CREATED:
       return "created";
+    case GRPC_ERROR_TIME_MAX:
+      GPR_UNREACHABLE_CODE(return "unknown");
   }
   GPR_UNREACHABLE_CODE(return "unknown");
 }
@@ -184,12 +152,36 @@ grpc_error *grpc_error_ref(grpc_error *err) {
 }
 #endif
 
+static void unref_errs(grpc_error *err) {
+  uint8_t slot = err->first_err;
+  while (slot != UINT8_MAX) {
+    grpc_linked_error *lerr = (grpc_linked_error *)(err->arena + slot);
+    GRPC_ERROR_UNREF(lerr->err);
+    GPR_ASSERT(err->last_err == slot ? lerr->next == UINT8_MAX
+                                     : lerr->next != UINT8_MAX);
+    slot = lerr->next;
+  }
+}
+
+static void unref_slice(grpc_slice slice) {
+  grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
+  grpc_slice_unref_internal(&exec_ctx, slice);
+  grpc_exec_ctx_finish(&exec_ctx);
+}
+
+static void unref_strs(grpc_error *err) {
+  for (size_t which = 0; which < GRPC_ERROR_STR_MAX; ++which) {
+    uint8_t slot = err->strs[which];
+    if (slot != UINT8_MAX) {
+      unref_slice(*(grpc_slice *)(err->arena + slot));
+    }
+  }
+}
+
 static void error_destroy(grpc_error *err) {
   GPR_ASSERT(!grpc_error_is_special(err));
-  gpr_avl_unref(err->ints);
-  gpr_avl_unref(err->strs);
-  gpr_avl_unref(err->errs);
-  gpr_avl_unref(err->times);
+  unref_errs(err);
+  unref_strs(err);
   gpr_free((void *)gpr_atm_acq_load(&err->error_string));
   gpr_free(err);
 }
@@ -213,67 +205,189 @@ void grpc_error_unref(grpc_error *err) {
 }
 #endif
 
+static uint8_t get_placement(grpc_error **err, size_t size) {
+  GPR_ASSERT(*err);
+  uint8_t slots = (uint8_t)(size / sizeof(intptr_t));
+  if ((*err)->arena_size + slots > (*err)->arena_capacity) {
+    (*err)->arena_capacity = (uint8_t)(3 * (*err)->arena_capacity / 2);
+    *err = gpr_realloc(
+        *err, sizeof(grpc_error) + (*err)->arena_capacity * sizeof(intptr_t));
+  }
+  uint8_t placement = (*err)->arena_size;
+  (*err)->arena_size = (uint8_t)((*err)->arena_size + slots);
+  return placement;
+}
+
+static void internal_set_int(grpc_error **err, grpc_error_ints which,
+                             intptr_t value) {
+  // GPR_ASSERT((*err)->ints[which] == UINT8_MAX); // TODO, enforce this
+  uint8_t slot = (*err)->ints[which];
+  if (slot == UINT8_MAX) {
+    slot = get_placement(err, sizeof(value));
+  }
+  (*err)->ints[which] = slot;
+  (*err)->arena[slot] = value;
+}
+
+static void internal_set_str(grpc_error **err, grpc_error_strs which,
+                             grpc_slice value) {
+  // GPR_ASSERT((*err)->strs[which] == UINT8_MAX); // TODO, enforce this
+  uint8_t slot = (*err)->strs[which];
+  if (slot == UINT8_MAX) {
+    slot = get_placement(err, sizeof(value));
+  } else {
+    unref_slice(*(grpc_slice *)((*err)->arena + slot));
+  }
+  (*err)->strs[which] = slot;
+  memcpy((*err)->arena + slot, &value, sizeof(value));
+}
+
+static void internal_set_time(grpc_error **err, grpc_error_times which,
+                              gpr_timespec value) {
+  // GPR_ASSERT((*err)->times[which] == UINT8_MAX); // TODO, enforce this
+  uint8_t slot = (*err)->times[which];
+  if (slot == UINT8_MAX) {
+    slot = get_placement(err, sizeof(value));
+  }
+  (*err)->times[which] = slot;
+  memcpy((*err)->arena + slot, &value, sizeof(value));
+}
+
+static void internal_add_error(grpc_error **err, grpc_error *new) {
+  grpc_linked_error new_last = {new, UINT8_MAX};
+  uint8_t slot = get_placement(err, sizeof(grpc_linked_error));
+  if ((*err)->first_err == UINT8_MAX) {
+    GPR_ASSERT((*err)->last_err == UINT8_MAX);
+    (*err)->last_err = slot;
+    (*err)->first_err = slot;
+  } else {
+    GPR_ASSERT((*err)->last_err != UINT8_MAX);
+    grpc_linked_error *old_last =
+        (grpc_linked_error *)((*err)->arena + (*err)->last_err);
+    old_last->next = slot;
+    (*err)->last_err = slot;
+  }
+  memcpy((*err)->arena + slot, &new_last, sizeof(grpc_linked_error));
+}
+
+#define SLOTS_PER_INT (sizeof(intptr_t) / sizeof(intptr_t))
+#define SLOTS_PER_STR (sizeof(grpc_slice) / sizeof(intptr_t))
+#define SLOTS_PER_TIME (sizeof(gpr_timespec) / sizeof(intptr_t))
+#define SLOTS_PER_LINKED_ERROR (sizeof(grpc_linked_error) / sizeof(intptr_t))
+
+// size of storing one int and two slices and a timespec. For line, desc, file,
+// and time created
+#define DEFAULT_ERROR_CAPACITY \
+  (SLOTS_PER_INT + (SLOTS_PER_STR * 2) + SLOTS_PER_TIME)
+
+// It is very common to include and extra int and string in an error
+#define SURPLUS_CAPACITY (2 * SLOTS_PER_INT + SLOTS_PER_TIME)
+
 grpc_error *grpc_error_create(const char *file, int line, const char *desc,
                               grpc_error **referencing,
                               size_t num_referencing) {
   GPR_TIMER_BEGIN("grpc_error_create", 0);
-  grpc_error *err = gpr_malloc(sizeof(*err));
+  uint8_t initial_arena_capacity = (uint8_t)(
+      DEFAULT_ERROR_CAPACITY +
+      (uint8_t)(num_referencing * SLOTS_PER_LINKED_ERROR) + SURPLUS_CAPACITY);
+  grpc_error *err =
+      gpr_malloc(sizeof(*err) + initial_arena_capacity * sizeof(intptr_t));
   if (err == NULL) {  // TODO(ctiller): make gpr_malloc return NULL
     return GRPC_ERROR_OOM;
   }
 #ifdef GRPC_ERROR_REFCOUNT_DEBUG
   gpr_log(GPR_DEBUG, "%p create [%s:%d]", err, file, line);
 #endif
-  err->ints = gpr_avl_add(gpr_avl_create(&avl_vtable_ints),
-                          (void *)(uintptr_t)GRPC_ERROR_INT_FILE_LINE,
-                          (void *)(uintptr_t)line);
-  err->strs = gpr_avl_add(
-      gpr_avl_add(gpr_avl_create(&avl_vtable_strs),
-                  (void *)(uintptr_t)GRPC_ERROR_STR_FILE, gpr_strdup(file)),
-      (void *)(uintptr_t)GRPC_ERROR_STR_DESCRIPTION, gpr_strdup(desc));
-  err->errs = gpr_avl_create(&avl_vtable_errs);
-  err->next_err = 0;
-  for (size_t i = 0; i < num_referencing; i++) {
+
+  err->arena_size = 0;
+  err->arena_capacity = initial_arena_capacity;
+  err->first_err = UINT8_MAX;
+  err->last_err = UINT8_MAX;
+
+  memset(err->ints, UINT8_MAX, GRPC_ERROR_INT_MAX);
+  memset(err->strs, UINT8_MAX, GRPC_ERROR_STR_MAX);
+  memset(err->times, UINT8_MAX, GRPC_ERROR_TIME_MAX);
+
+  internal_set_int(&err, GRPC_ERROR_INT_FILE_LINE, line);
+  internal_set_str(&err, GRPC_ERROR_STR_FILE,
+                   grpc_slice_from_static_string(file));
+  internal_set_str(
+      &err, GRPC_ERROR_STR_DESCRIPTION,
+      grpc_slice_from_copied_buffer(
+          desc,
+          strlen(desc) +
+              1));  // TODO, pull this up.  // TODO(ncteisen), pull this up.
+
+  for (size_t i = 0; i < num_referencing; ++i) {
     if (referencing[i] == GRPC_ERROR_NONE) continue;
-    err->errs = gpr_avl_add(err->errs, (void *)(err->next_err++),
-                            GRPC_ERROR_REF(referencing[i]));
+    internal_add_error(
+        &err,
+        GRPC_ERROR_REF(
+            referencing[i]));  // TODO(ncteisen), change ownership semantics
   }
-  err->times = gpr_avl_add(gpr_avl_create(&avl_vtable_times),
-                           (void *)(uintptr_t)GRPC_ERROR_TIME_CREATED,
-                           box_time(gpr_now(GPR_CLOCK_REALTIME)));
+
+  internal_set_time(&err, GRPC_ERROR_TIME_CREATED, gpr_now(GPR_CLOCK_REALTIME));
+
   gpr_atm_no_barrier_store(&err->error_string, 0);
   gpr_ref_init(&err->refs, 1);
   GPR_TIMER_END("grpc_error_create", 0);
   return err;
 }
 
+static void ref_strs(grpc_error *err) {
+  for (size_t i = 0; i < GRPC_ERROR_STR_MAX; ++i) {
+    uint8_t slot = err->strs[i];
+    if (slot != UINT8_MAX) {
+      grpc_slice_ref_internal(*(grpc_slice *)(err->arena + slot));
+    }
+  }
+}
+
+static void ref_errs(grpc_error *err) {
+  uint8_t slot = err->first_err;
+  while (slot != UINT8_MAX) {
+    grpc_linked_error *lerr = (grpc_linked_error *)(err->arena + slot);
+    GRPC_ERROR_REF(lerr->err);
+    slot = lerr->next;
+  }
+}
+
 static grpc_error *copy_error_and_unref(grpc_error *in) {
   GPR_TIMER_BEGIN("copy_error_and_unref", 0);
   grpc_error *out;
   if (grpc_error_is_special(in)) {
-    if (in == GRPC_ERROR_NONE)
-      out = grpc_error_set_int(GRPC_ERROR_CREATE("no error"),
-                               GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_OK);
-    else if (in == GRPC_ERROR_OOM)
-      out = GRPC_ERROR_CREATE("oom");
-    else if (in == GRPC_ERROR_CANCELLED)
-      out =
-          grpc_error_set_int(GRPC_ERROR_CREATE("cancelled"),
-                             GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_CANCELLED);
-    else
-      out = GRPC_ERROR_CREATE("unknown");
+    out = GRPC_ERROR_CREATE("unknown");
+    if (in == GRPC_ERROR_NONE) {
+      internal_set_str(&out, GRPC_ERROR_STR_DESCRIPTION,
+                       grpc_slice_from_static_string("no error"));
+      internal_set_int(&out, GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_OK);
+    } else if (in == GRPC_ERROR_OOM) {
+      internal_set_str(&out, GRPC_ERROR_STR_DESCRIPTION,
+                       grpc_slice_from_static_string("oom"));
+    } else if (in == GRPC_ERROR_CANCELLED) {
+      internal_set_str(&out, GRPC_ERROR_STR_DESCRIPTION,
+                       grpc_slice_from_static_string("cancelled"));
+      internal_set_int(&out, GRPC_ERROR_INT_GRPC_STATUS, GRPC_STATUS_CANCELLED);
+    }
+  } else if (gpr_ref_is_unique(&in->refs)) {
+    out = in;
   } else {
-    out = gpr_malloc(sizeof(*out));
+    uint8_t new_arena_capacity = in->arena_capacity;
+    // the returned err will be added to, so we ensure this is room to avoid
+    // unneeded allocations.
+    if (in->arena_capacity - in->arena_size < (uint8_t)SLOTS_PER_STR) {
+      new_arena_capacity = (uint8_t)(3 * new_arena_capacity / 2);
+    }
+    out = gpr_malloc(sizeof(*in) + new_arena_capacity * sizeof(intptr_t));
 #ifdef GRPC_ERROR_REFCOUNT_DEBUG
     gpr_log(GPR_DEBUG, "%p create copying %p", out, in);
 #endif
-    out->ints = gpr_avl_ref(in->ints);
-    out->strs = gpr_avl_ref(in->strs);
-    out->errs = gpr_avl_ref(in->errs);
-    out->times = gpr_avl_ref(in->times);
+    memcpy(out, in, sizeof(*in) + in->arena_size * sizeof(intptr_t));
+    out->arena_capacity = new_arena_capacity;
     gpr_atm_no_barrier_store(&out->error_string, 0);
-    out->next_err = in->next_err;
     gpr_ref_init(&out->refs, 1);
+    ref_strs(out);
+    ref_errs(out);
     GRPC_ERROR_UNREF(in);
   }
   GPR_TIMER_END("copy_error_and_unref", 0);
@@ -284,7 +398,7 @@ grpc_error *grpc_error_set_int(grpc_error *src, grpc_error_ints which,
                                intptr_t value) {
   GPR_TIMER_BEGIN("grpc_error_set_int", 0);
   grpc_error *new = copy_error_and_unref(src);
-  new->ints = gpr_avl_add(new->ints, (void *)(uintptr_t)which, (void *)value);
+  internal_set_int(&new, which, value);
   GPR_TIMER_END("grpc_error_set_int", 0);
   return new;
 }
@@ -302,7 +416,6 @@ static special_error_status_map error_status_map[] = {
 
 bool grpc_error_get_int(grpc_error *err, grpc_error_ints which, intptr_t *p) {
   GPR_TIMER_BEGIN("grpc_error_get_int", 0);
-  void *pp;
   if (grpc_error_is_special(err)) {
     if (which == GRPC_ERROR_INT_GRPC_STATUS) {
       for (size_t i = 0; i < GPR_ARRAY_SIZE(error_status_map); i++) {
@@ -316,8 +429,9 @@ bool grpc_error_get_int(grpc_error *err, grpc_error_ints which, intptr_t *p) {
     GPR_TIMER_END("grpc_error_get_int", 0);
     return false;
   }
-  if (gpr_avl_maybe_get(err->ints, (void *)(uintptr_t)which, &pp)) {
-    if (p != NULL) *p = (intptr_t)pp;
+  uint8_t slot = err->ints[which];
+  if (slot != UINT8_MAX) {
+    if (p != NULL) *p = err->arena[slot];
     GPR_TIMER_END("grpc_error_get_int", 0);
     return true;
   }
@@ -329,8 +443,9 @@ grpc_error *grpc_error_set_str(grpc_error *src, grpc_error_strs which,
                                const char *value) {
   GPR_TIMER_BEGIN("grpc_error_set_str", 0);
   grpc_error *new = copy_error_and_unref(src);
-  new->strs =
-      gpr_avl_add(new->strs, (void *)(uintptr_t)which, gpr_strdup(value));
+  internal_set_str(&new, which,
+                   grpc_slice_from_copied_buffer(
+                       value, strlen(value) + 1));  // TODO, pull this up.
   GPR_TIMER_END("grpc_error_set_str", 0);
   return new;
 }
@@ -346,13 +461,19 @@ const char *grpc_error_get_str(grpc_error *err, grpc_error_strs which) {
     }
     return NULL;
   }
-  return gpr_avl_get(err->strs, (void *)(uintptr_t)which);
+  uint8_t slot = err->strs[which];
+  if (slot != UINT8_MAX) {
+    return (const char *)GRPC_SLICE_START_PTR(
+        *(grpc_slice *)(err->arena + slot));
+  } else {
+    return NULL;
+  }
 }
 
 grpc_error *grpc_error_add_child(grpc_error *src, grpc_error *child) {
   GPR_TIMER_BEGIN("grpc_error_add_child", 0);
   grpc_error *new = copy_error_and_unref(src);
-  new->errs = gpr_avl_add(new->errs, (void *)(new->next_err++), child);
+  internal_add_error(&new, child);
   GPR_TIMER_END("grpc_error_add_child", 0);
   return new;
 }
@@ -372,42 +493,6 @@ typedef struct {
   size_t cap_kvs;
 } kv_pairs;
 
-static void append_kv(kv_pairs *kvs, char *key, char *value) {
-  if (kvs->num_kvs == kvs->cap_kvs) {
-    kvs->cap_kvs = GPR_MAX(3 * kvs->cap_kvs / 2, 4);
-    kvs->kvs = gpr_realloc(kvs->kvs, sizeof(*kvs->kvs) * kvs->cap_kvs);
-  }
-  kvs->kvs[kvs->num_kvs].key = key;
-  kvs->kvs[kvs->num_kvs].value = value;
-  kvs->num_kvs++;
-}
-
-static void collect_kvs(gpr_avl_node *node, char *key(void *k),
-                        char *fmt(void *v), kv_pairs *kvs) {
-  if (node == NULL) return;
-  append_kv(kvs, key(node->key), fmt(node->value));
-  collect_kvs(node->left, key, fmt, kvs);
-  collect_kvs(node->right, key, fmt, kvs);
-}
-
-static char *key_int(void *p) {
-  return gpr_strdup(error_int_name((grpc_error_ints)(uintptr_t)p));
-}
-
-static char *key_str(void *p) {
-  return gpr_strdup(error_str_name((grpc_error_strs)(uintptr_t)p));
-}
-
-static char *key_time(void *p) {
-  return gpr_strdup(error_time_name((grpc_error_times)(uintptr_t)p));
-}
-
-static char *fmt_int(void *p) {
-  char *s;
-  gpr_asprintf(&s, "%" PRIdPTR, (intptr_t)p);
-  return s;
-}
-
 static void append_chr(char c, char **s, size_t *sz, size_t *cap) {
   if (*sz == *cap) {
     *cap = GPR_MAX(8, 3 * *cap / 2);
@@ -459,6 +544,40 @@ static void append_esc_str(const char *str, char **s, size_t *sz, size_t *cap) {
   append_chr('"', s, sz, cap);
 }
 
+static void append_kv(kv_pairs *kvs, char *key, char *value) {
+  if (kvs->num_kvs == kvs->cap_kvs) {
+    kvs->cap_kvs = GPR_MAX(3 * kvs->cap_kvs / 2, 4);
+    kvs->kvs = gpr_realloc(kvs->kvs, sizeof(*kvs->kvs) * kvs->cap_kvs);
+  }
+  kvs->kvs[kvs->num_kvs].key = key;
+  kvs->kvs[kvs->num_kvs].value = value;
+  kvs->num_kvs++;
+}
+
+static char *key_int(grpc_error_ints which) {
+  return gpr_strdup(error_int_name(which));
+}
+
+static char *fmt_int(intptr_t p) {
+  char *s;
+  gpr_asprintf(&s, "%" PRIdPTR, p);
+  return s;
+}
+
+static void collect_ints_kvs(grpc_error *err, kv_pairs *kvs) {
+  for (size_t which = 0; which < GRPC_ERROR_INT_MAX; ++which) {
+    uint8_t slot = err->ints[which];
+    if (slot != UINT8_MAX) {
+      append_kv(kvs, key_int((grpc_error_ints)which),
+                fmt_int(err->arena[slot]));
+    }
+  }
+}
+
+static char *key_str(grpc_error_strs which) {
+  return gpr_strdup(error_str_name(which));
+}
+
 static char *fmt_str(void *p) {
   char *s = NULL;
   size_t sz = 0;
@@ -468,8 +587,22 @@ static char *fmt_str(void *p) {
   return s;
 }
 
-static char *fmt_time(void *p) {
-  gpr_timespec tm = *(gpr_timespec *)p;
+static void collect_strs_kvs(grpc_error *err, kv_pairs *kvs) {
+  for (size_t which = 0; which < GRPC_ERROR_STR_MAX; ++which) {
+    uint8_t slot = err->strs[which];
+    if (slot != UINT8_MAX) {
+      append_kv(
+          kvs, key_str((grpc_error_strs)which),
+          fmt_str(GRPC_SLICE_START_PTR(*(grpc_slice *)(err->arena + slot))));
+    }
+  }
+}
+
+static char *key_time(grpc_error_times which) {
+  return gpr_strdup(error_time_name(which));
+}
+
+static char *fmt_time(gpr_timespec tm) {
   char *out;
   char *pfx = "!!";
   switch (tm.clock_type) {
@@ -490,24 +623,37 @@ static char *fmt_time(void *p) {
   return out;
 }
 
-static void add_errs(gpr_avl_node *n, char **s, size_t *sz, size_t *cap,
-                     bool *first) {
-  if (n == NULL) return;
-  add_errs(n->left, s, sz, cap, first);
-  if (!*first) append_chr(',', s, sz, cap);
-  *first = false;
-  const char *e = grpc_error_string(n->value);
-  append_str(e, s, sz, cap);
-  add_errs(n->right, s, sz, cap, first);
+static void collect_times_kvs(grpc_error *err, kv_pairs *kvs) {
+  for (size_t which = 0; which < GRPC_ERROR_TIME_MAX; ++which) {
+    uint8_t slot = err->times[which];
+    if (slot != UINT8_MAX) {
+      append_kv(kvs, key_time((grpc_error_times)which),
+                fmt_time(*(gpr_timespec *)(err->arena + slot)));
+    }
+  }
+}
+
+static void add_errs(grpc_error *err, char **s, size_t *sz, size_t *cap) {
+  uint8_t slot = err->first_err;
+  bool first = true;
+  while (slot != UINT8_MAX) {
+    grpc_linked_error *lerr = (grpc_linked_error *)(err->arena + slot);
+    if (!first) append_chr(',', s, sz, cap);
+    first = false;
+    const char *e = grpc_error_string(lerr->err);
+    append_str(e, s, sz, cap);
+    GPR_ASSERT(err->last_err == slot ? lerr->next == UINT8_MAX
+                                     : lerr->next != UINT8_MAX);
+    slot = lerr->next;
+  }
 }
 
 static char *errs_string(grpc_error *err) {
   char *s = NULL;
   size_t sz = 0;
   size_t cap = 0;
-  bool first = true;
   append_chr('[', &s, &sz, &cap);
-  add_errs(err->errs.root, &s, &sz, &cap, &first);
+  add_errs(err, &s, &sz, &cap);
   append_chr(']', &s, &sz, &cap);
   append_chr(0, &s, &sz, &cap);
   return s;
@@ -555,10 +701,10 @@ const char *grpc_error_string(grpc_error *err) {
   kv_pairs kvs;
   memset(&kvs, 0, sizeof(kvs));
 
-  collect_kvs(err->ints.root, key_int, fmt_int, &kvs);
-  collect_kvs(err->strs.root, key_str, fmt_str, &kvs);
-  collect_kvs(err->times.root, key_time, fmt_time, &kvs);
-  if (!gpr_avl_is_empty(err->errs)) {
+  collect_ints_kvs(err, &kvs);
+  collect_strs_kvs(err, &kvs);
+  collect_times_kvs(err, &kvs);
+  if (err->first_err != UINT8_MAX) {
     append_kv(&kvs, gpr_strdup("referenced_errors"), errs_string(err));
   }
 
diff --git a/src/core/lib/iomgr/error.h b/src/core/lib/iomgr/error.h
index 2613512acb..eb953947ae 100644
--- a/src/core/lib/iomgr/error.h
+++ b/src/core/lib/iomgr/error.h
@@ -102,6 +102,9 @@ typedef enum {
   GRPC_ERROR_INT_LIMIT,
   /// chttp2: did the error occur while a write was in progress
   GRPC_ERROR_INT_OCCURRED_DURING_WRITE,
+
+  /// Must always be last
+  GRPC_ERROR_INT_MAX,
 } grpc_error_ints;
 
 typedef enum {
@@ -129,11 +132,17 @@ typedef enum {
   GRPC_ERROR_STR_KEY,
   /// value associated with the error
   GRPC_ERROR_STR_VALUE,
+
+  /// Must always be last
+  GRPC_ERROR_STR_MAX,
 } grpc_error_strs;
 
 typedef enum {
   /// timestamp of error creation
   GRPC_ERROR_TIME_CREATED,
+
+  /// Must always be last
+  GRPC_ERROR_TIME_MAX,
 } grpc_error_times;
 
 /// The following "special" errors can be propagated without allocating memory.
@@ -184,8 +193,6 @@ void grpc_error_unref(grpc_error *err);
 grpc_error *grpc_error_set_int(grpc_error *src, grpc_error_ints which,
                                intptr_t value) GRPC_MUST_USE_RESULT;
 bool grpc_error_get_int(grpc_error *error, grpc_error_ints which, intptr_t *p);
-grpc_error *grpc_error_set_time(grpc_error *src, grpc_error_times which,
-                                gpr_timespec value) GRPC_MUST_USE_RESULT;
 grpc_error *grpc_error_set_str(grpc_error *src, grpc_error_strs which,
                                const char *value) GRPC_MUST_USE_RESULT;
 /// Returns NULL if the specified string is not set.
diff --git a/src/core/lib/iomgr/error_internal.h b/src/core/lib/iomgr/error_internal.h
index 1c89ead4ed..fb4814e41f 100644
--- a/src/core/lib/iomgr/error_internal.h
+++ b/src/core/lib/iomgr/error_internal.h
@@ -35,18 +35,28 @@
 #define GRPC_CORE_LIB_IOMGR_ERROR_INTERNAL_H
 
 #include <inttypes.h>
-#include <stdbool.h>
+#include <stdbool.h>  // TODO, do we need this?
 
-#include <grpc/support/avl.h>
+#include <grpc/support/sync.h>
+
+typedef struct grpc_linked_error grpc_linked_error;
+
+struct grpc_linked_error {
+  grpc_error *err;
+  uint8_t next;
+};
 
 struct grpc_error {
   gpr_refcount refs;
-  gpr_avl ints;
-  gpr_avl strs;
-  gpr_avl times;
-  gpr_avl errs;
-  uintptr_t next_err;
+  uint8_t ints[GRPC_ERROR_INT_MAX];
+  uint8_t strs[GRPC_ERROR_STR_MAX];
+  uint8_t times[GRPC_ERROR_TIME_MAX];
+  uint8_t first_err;
+  uint8_t last_err;
   gpr_atm error_string;
+  uint8_t arena_size;
+  uint8_t arena_capacity;
+  intptr_t arena[0];
 };
 
 bool grpc_error_is_special(grpc_error *err);
diff --git a/src/core/lib/iomgr/pollset_uv.c b/src/core/lib/iomgr/pollset_uv.c
index af33949c69..a2f81bcd78 100644
--- a/src/core/lib/iomgr/pollset_uv.c
+++ b/src/core/lib/iomgr/pollset_uv.c
@@ -39,6 +39,7 @@
 
 #include <string.h>
 
+#include <grpc/support/alloc.h>
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 
@@ -61,25 +62,30 @@ gpr_mu grpc_polling_mu;
    immediately in the next loop iteration.
    Note: In the future, if there is a bug that involves missing wakeups in the
    future, try adding a uv_async_t to kick the loop differently */
-uv_timer_t dummy_uv_handle;
+uv_timer_t *dummy_uv_handle;
 
 size_t grpc_pollset_size() { return sizeof(grpc_pollset); }
 
 void dummy_timer_cb(uv_timer_t *handle) {}
 
+void dummy_handle_close_cb(uv_handle_t *handle) { gpr_free(handle); }
+
 void grpc_pollset_global_init(void) {
   gpr_mu_init(&grpc_polling_mu);
-  uv_timer_init(uv_default_loop(), &dummy_uv_handle);
+  dummy_uv_handle = gpr_malloc(sizeof(uv_timer_t));
+  uv_timer_init(uv_default_loop(), dummy_uv_handle);
   grpc_pollset_work_run_loop = 1;
 }
 
-static void timer_close_cb(uv_handle_t *handle) { handle->data = (void *)1; }
-
 void grpc_pollset_global_shutdown(void) {
   gpr_mu_destroy(&grpc_polling_mu);
-  uv_close((uv_handle_t *)&dummy_uv_handle, timer_close_cb);
+  uv_close((uv_handle_t *)dummy_uv_handle, dummy_handle_close_cb);
 }
 
+static void timer_run_cb(uv_timer_t *timer) {}
+
+static void timer_close_cb(uv_handle_t *handle) { handle->data = (void *)1; }
+
 void grpc_pollset_init(grpc_pollset *pollset, gpr_mu **mu) {
   *mu = &grpc_polling_mu;
   uv_timer_init(uv_default_loop(), &pollset->timer);
@@ -95,7 +101,7 @@ void grpc_pollset_shutdown(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
     uv_run(uv_default_loop(), UV_RUN_NOWAIT);
   } else {
     // kick the loop once
-    uv_timer_start(&dummy_uv_handle, dummy_timer_cb, 0, 0);
+    uv_timer_start(dummy_uv_handle, dummy_timer_cb, 0, 0);
   }
   grpc_closure_sched(exec_ctx, closure, GRPC_ERROR_NONE);
 }
@@ -111,8 +117,6 @@ void grpc_pollset_destroy(grpc_pollset *pollset) {
   }
 }
 
-static void timer_run_cb(uv_timer_t *timer) {}
-
 grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
                               grpc_pollset_worker **worker_hdl,
                               gpr_timespec now, gpr_timespec deadline) {
@@ -145,7 +149,7 @@ grpc_error *grpc_pollset_work(grpc_exec_ctx *exec_ctx, grpc_pollset *pollset,
 
 grpc_error *grpc_pollset_kick(grpc_pollset *pollset,
                               grpc_pollset_worker *specific_worker) {
-  uv_timer_start(&dummy_uv_handle, dummy_timer_cb, 0, 0);
+  uv_timer_start(dummy_uv_handle, dummy_timer_cb, 0, 0);
   return GRPC_ERROR_NONE;
 }
 
diff --git a/src/core/lib/iomgr/resolve_address_uv.c b/src/core/lib/iomgr/resolve_address_uv.c
index 79ff910738..4d715be94c 100644
--- a/src/core/lib/iomgr/resolve_address_uv.c
+++ b/src/core/lib/iomgr/resolve_address_uv.c
@@ -40,6 +40,7 @@
 #include <grpc/support/host_port.h>
 #include <grpc/support/log.h>
 #include <grpc/support/string_util.h>
+#include <grpc/support/useful.h>
 
 #include "src/core/lib/iomgr/closure.h"
 #include "src/core/lib/iomgr/error.h"
@@ -54,8 +55,36 @@ typedef struct request {
   grpc_closure *on_done;
   grpc_resolved_addresses **addresses;
   struct addrinfo *hints;
+  char *host;
+  char *port;
 } request;
 
+static int retry_named_port_failure(int status, request *r,
+                                    uv_getaddrinfo_cb getaddrinfo_cb) {
+  if (status != 0) {
+    // This loop is copied from resolve_address_posix.c
+    char *svc[][2] = {{"http", "80"}, {"https", "443"}};
+    for (size_t i = 0; i < GPR_ARRAY_SIZE(svc); i++) {
+      if (strcmp(r->port, svc[i][0]) == 0) {
+        int retry_status;
+        uv_getaddrinfo_t *req = gpr_malloc(sizeof(uv_getaddrinfo_t));
+        req->data = r;
+        retry_status = uv_getaddrinfo(uv_default_loop(), req, getaddrinfo_cb,
+                                      r->host, svc[i][1], r->hints);
+        if (retry_status < 0 || getaddrinfo_cb == NULL) {
+          // The callback will not be called
+          gpr_free(req);
+        }
+        return retry_status;
+      }
+    }
+  }
+  /* If this function calls uv_getaddrinfo, it will return that function's
+     return value. That function only returns numbers <=0, so we can safely
+     return 1 to indicate that we never retried */
+  return 1;
+}
+
 static grpc_error *handle_addrinfo_result(int status, struct addrinfo *result,
                                           grpc_resolved_addresses **addresses) {
   struct addrinfo *resp;
@@ -97,13 +126,21 @@ static void getaddrinfo_callback(uv_getaddrinfo_t *req, int status,
   request *r = (request *)req->data;
   grpc_exec_ctx exec_ctx = GRPC_EXEC_CTX_INIT;
   grpc_error *error;
+  int retry_status;
+
+  gpr_free(req);
+  retry_status = retry_named_port_failure(status, r, getaddrinfo_callback);
+  if (retry_status == 0) {
+    // The request is being retried. Nothing should be done here
+    return;
+  }
+  /* Either no retry was attempted, or the retry failed. Either way, the
+     original error probably has more interesting information */
   error = handle_addrinfo_result(status, res, r->addresses);
   grpc_closure_sched(&exec_ctx, r->on_done, error);
   grpc_exec_ctx_finish(&exec_ctx);
-
   gpr_free(r->hints);
   gpr_free(r);
-  gpr_free(req);
   uv_freeaddrinfo(res);
 }
 
@@ -143,6 +180,7 @@ static grpc_error *blocking_resolve_address_impl(
   uv_getaddrinfo_t req;
   int s;
   grpc_error *err;
+  int retry_status;
 
   req.addrinfo = NULL;
 
@@ -158,6 +196,12 @@ static grpc_error *blocking_resolve_address_impl(
   hints.ai_flags = AI_PASSIVE;     /* for wildcard IP address */
 
   s = uv_getaddrinfo(uv_default_loop(), &req, NULL, host, port, &hints);
+  request r = {
+      .addresses = addresses, .hints = &hints, .host = host, .port = port};
+  retry_status = retry_named_port_failure(s, &r, NULL);
+  if (retry_status <= 0) {
+    s = retry_status;
+  }
   err = handle_addrinfo_result(s, req.addrinfo, addresses);
 
 done:
@@ -200,6 +244,8 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
   r = gpr_malloc(sizeof(request));
   r->on_done = on_done;
   r->addresses = addrs;
+  r->host = host;
+  r->port = port;
   req = gpr_malloc(sizeof(uv_getaddrinfo_t));
   req->data = r;
 
@@ -222,6 +268,8 @@ static void resolve_address_impl(grpc_exec_ctx *exec_ctx, const char *name,
     gpr_free(r);
     gpr_free(req);
     gpr_free(hints);
+    gpr_free(host);
+    gpr_free(port);
   }
 }
 
diff --git a/src/core/lib/iomgr/sockaddr_utils.c b/src/core/lib/iomgr/sockaddr_utils.c
index ffa62cb53c..9d2732666b 100644
--- a/src/core/lib/iomgr/sockaddr_utils.c
+++ b/src/core/lib/iomgr/sockaddr_utils.c
@@ -162,6 +162,7 @@ int grpc_sockaddr_to_string(char **out,
   char ntop_buf[INET6_ADDRSTRLEN];
   const void *ip = NULL;
   int port;
+  uint32_t sin6_scope_id = 0;
   int ret;
 
   *out = NULL;
@@ -177,10 +178,19 @@ int grpc_sockaddr_to_string(char **out,
     const struct sockaddr_in6 *addr6 = (const struct sockaddr_in6 *)addr;
     ip = &addr6->sin6_addr;
     port = ntohs(addr6->sin6_port);
+    sin6_scope_id = addr6->sin6_scope_id;
   }
   if (ip != NULL &&
       grpc_inet_ntop(addr->sa_family, ip, ntop_buf, sizeof(ntop_buf)) != NULL) {
-    ret = gpr_join_host_port(out, ntop_buf, port);
+    if (sin6_scope_id != 0) {
+      char *host_with_scope;
+      /* Enclose sin6_scope_id with the format defined in RFC 6784 section 2. */
+      gpr_asprintf(&host_with_scope, "%s%%25%" PRIu32, ntop_buf, sin6_scope_id);
+      ret = gpr_join_host_port(out, host_with_scope, port);
+      gpr_free(host_with_scope);
+    } else {
+      ret = gpr_join_host_port(out, ntop_buf, port);
+    }
   } else {
     ret = gpr_asprintf(out, "(sockaddr family=%d)", addr->sa_family);
   }
diff --git a/src/core/lib/iomgr/tcp_client_uv.c b/src/core/lib/iomgr/tcp_client_uv.c
index ae66577caf..618483d9cb 100644
--- a/src/core/lib/iomgr/tcp_client_uv.c
+++ b/src/core/lib/iomgr/tcp_client_uv.c
@@ -76,7 +76,6 @@ static void uv_tc_on_alarm(grpc_exec_ctx *exec_ctx, void *acp,
     const char *str = grpc_error_string(error);
     gpr_log(GPR_DEBUG, "CLIENT_CONNECT: %s: on_alarm: error=%s",
             connect->addr_name, str);
-    grpc_error_free_string(str);
   }
   if (error == GRPC_ERROR_NONE) {
     /* error == NONE implies that the timer ran out, and wasn't cancelled. If
diff --git a/src/core/lib/iomgr/tcp_server_posix.c b/src/core/lib/iomgr/tcp_server_posix.c
index 36f878fdd4..5f286a6723 100644
--- a/src/core/lib/iomgr/tcp_server_posix.c
+++ b/src/core/lib/iomgr/tcp_server_posix.c
@@ -114,6 +114,8 @@ struct grpc_tcp_server {
 
   /* is this server shutting down? */
   bool shutdown;
+  /* have listeners been shutdown? */
+  bool shutdown_listeners;
   /* use SO_REUSEPORT */
   bool so_reuseport;
   /* expand wildcard addresses to a list of all local addresses */
@@ -161,7 +163,7 @@ grpc_error *grpc_tcp_server_create(grpc_exec_ctx *exec_ctx,
                                    grpc_tcp_server **server) {
   gpr_once_init(&check_init, init);
 
-  grpc_tcp_server *s = gpr_malloc(sizeof(grpc_tcp_server));
+  grpc_tcp_server *s = gpr_zalloc(sizeof(grpc_tcp_server));
   s->so_reuseport = has_so_reuseport;
   s->resource_quota = grpc_resource_quota_create(NULL);
   s->expand_wildcard_addrs = false;
@@ -422,7 +424,14 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
           grpc_fd_notify_on_read(exec_ctx, sp->emfd, &sp->read_closure);
           return;
         default:
-          gpr_log(GPR_ERROR, "Failed accept4: %s", strerror(errno));
+          gpr_mu_lock(&sp->server->mu);
+          if (!sp->server->shutdown_listeners) {
+            gpr_log(GPR_ERROR, "Failed accept4: %s", strerror(errno));
+          } else {
+            /* if we have shutdown listeners, accept4 could fail, and we
+               needn't notify users */
+          }
+          gpr_mu_unlock(&sp->server->mu);
           goto error;
       }
     }
@@ -438,11 +447,6 @@ static void on_read(grpc_exec_ctx *exec_ctx, void *arg, grpc_error *err) {
 
     grpc_fd *fdobj = grpc_fd_create(fd, name);
 
-    if (read_notifier_pollset == NULL) {
-      gpr_log(GPR_ERROR, "Read notifier pollset is not set on the fd");
-      goto error;
-    }
-
     grpc_pollset_add_fd(exec_ctx, read_notifier_pollset, fdobj);
 
     // Create acceptor.
@@ -941,6 +945,7 @@ void grpc_tcp_server_unref(grpc_exec_ctx *exec_ctx, grpc_tcp_server *s) {
 void grpc_tcp_server_shutdown_listeners(grpc_exec_ctx *exec_ctx,
                                         grpc_tcp_server *s) {
   gpr_mu_lock(&s->mu);
+  s->shutdown_listeners = true;
   /* shutdown all fd's */
   if (s->active_ports) {
     grpc_tcp_listener *sp;
diff --git a/src/core/lib/iomgr/udp_server.c b/src/core/lib/iomgr/udp_server.c
index 2a1c8d39fa..d1bcd89af1 100644
--- a/src/core/lib/iomgr/udp_server.c
+++ b/src/core/lib/iomgr/udp_server.c
@@ -485,7 +485,11 @@ void grpc_udp_server_start(grpc_exec_ctx *exec_ctx, grpc_udp_server *s,
                       grpc_schedule_on_exec_ctx);
     grpc_fd_notify_on_write(exec_ctx, sp->emfd, &sp->write_closure);
 
-    s->active_ports++;
+    /* Registered for both read and write callbacks: increment active_ports
+     * twice to account for this, and delay free-ing of memory until both
+     * on_read and on_write have fired. */
+    s->active_ports += 2;
+
     sp = sp->next;
   }
 
diff --git a/src/core/lib/iomgr/wakeup_fd_posix.h b/src/core/lib/iomgr/wakeup_fd_posix.h
index 71d32d97ba..c8dd242c75 100644
--- a/src/core/lib/iomgr/wakeup_fd_posix.h
+++ b/src/core/lib/iomgr/wakeup_fd_posix.h
@@ -46,7 +46,7 @@
  *
  * Setup:
  * 1. Before calling anything, call global_init() at least once.
- * 1. Call grpc_wakeup_fd_create() to get a wakeup_fd.
+ * 1. Call grpc_wakeup_fd_init() to set up a wakeup_fd.
  * 2. Add the result of GRPC_WAKEUP_FD_FD to the set of monitored file
  *    descriptors for the poll() style API you are using. Monitor the file
  *    descriptor for readability.
diff --git a/src/core/lib/support/sync.c b/src/core/lib/support/sync.c
index 44b83f8175..b52f004f74 100644
--- a/src/core/lib/support/sync.c
+++ b/src/core/lib/support/sync.c
@@ -37,6 +37,8 @@
 #include <grpc/support/log.h>
 #include <grpc/support/sync.h>
 
+#include <assert.h>
+
 /* Number of mutexes to allocate for events, to avoid lock contention.
    Should be a prime. */
 enum { event_sync_partitions = 31 };
@@ -99,8 +101,12 @@ void gpr_ref_init(gpr_refcount *r, int n) { gpr_atm_rel_store(&r->count, n); }
 void gpr_ref(gpr_refcount *r) { gpr_atm_no_barrier_fetch_add(&r->count, 1); }
 
 void gpr_ref_non_zero(gpr_refcount *r) {
+#ifndef NDEBUG
   gpr_atm prior = gpr_atm_no_barrier_fetch_add(&r->count, 1);
-  GPR_ASSERT(prior > 0);
+  assert(prior > 0);
+#else
+  gpr_ref(r);
+#endif
 }
 
 void gpr_refn(gpr_refcount *r, int n) {
@@ -113,6 +119,10 @@ int gpr_unref(gpr_refcount *r) {
   return prior == 1;
 }
 
+int gpr_ref_is_unique(gpr_refcount *r) {
+  return gpr_atm_acq_load(&r->count) == 1;
+}
+
 void gpr_stats_init(gpr_stats_counter *c, intptr_t n) {
   gpr_atm_rel_store(&c->value, n);
 }
diff --git a/src/core/lib/surface/call.c b/src/core/lib/surface/call.c
index cc57654ea4..c2547c5147 100644
--- a/src/core/lib/surface/call.c
+++ b/src/core/lib/surface/call.c
@@ -161,6 +161,7 @@ struct grpc_call {
   bool receiving_message;
   bool requested_final_op;
   bool received_final_op;
+  bool sent_any_op;
 
   /* have we received initial metadata */
   bool has_initial_md_been_received;
@@ -488,7 +489,7 @@ void grpc_call_destroy(grpc_call *c) {
   gpr_mu_lock(&c->mu);
   GPR_ASSERT(!c->destroy_called);
   c->destroy_called = 1;
-  cancel = !c->received_final_op;
+  cancel = c->sent_any_op && !c->received_final_op;
   gpr_mu_unlock(&c->mu);
   if (cancel) {
     cancel_with_error(&exec_ctx, c, STATUS_FROM_API_OVERRIDE,
@@ -1678,6 +1679,7 @@ static grpc_call_error call_start_batch(grpc_exec_ctx *exec_ctx,
   grpc_closure_init(&bctl->finish_batch, finish_batch, bctl,
                     grpc_schedule_on_exec_ctx);
   stream_op->on_complete = &bctl->finish_batch;
+  call->sent_any_op = true;
   gpr_mu_unlock(&call->mu);
 
   execute_op(exec_ctx, call, stream_op);
diff --git a/src/core/lib/transport/error_utils.c b/src/core/lib/transport/error_utils.c
index da77828d9c..ef55e561fb 100644
--- a/src/core/lib/transport/error_utils.c
+++ b/src/core/lib/transport/error_utils.c
@@ -44,12 +44,12 @@ static grpc_error *recursively_find_error_with_field(grpc_error *error,
   }
   if (grpc_error_is_special(error)) return NULL;
   // Otherwise, search through its children.
-  intptr_t key = 0;
-  while (true) {
-    grpc_error *child_error = gpr_avl_get(error->errs, (void *)key++);
-    if (child_error == NULL) break;
-    grpc_error *result = recursively_find_error_with_field(child_error, which);
-    if (result != NULL) return result;
+  uint8_t slot = error->first_err;
+  while (slot != UINT8_MAX) {
+    grpc_linked_error *lerr = (grpc_linked_error *)(error->arena + slot);
+    grpc_error *result = recursively_find_error_with_field(lerr->err, which);
+    if (result) return result;
+    slot = lerr->next;
   }
   return NULL;
 }
@@ -112,13 +112,13 @@ bool grpc_error_has_clear_grpc_status(grpc_error *error) {
   if (grpc_error_get_int(error, GRPC_ERROR_INT_GRPC_STATUS, NULL)) {
     return true;
   }
-  intptr_t key = 0;
-  while (true) {
-    grpc_error *child_error = gpr_avl_get(error->errs, (void *)key++);
-    if (child_error == NULL) break;
-    if (grpc_error_has_clear_grpc_status(child_error)) {
+  uint8_t slot = error->first_err;
+  while (slot != UINT8_MAX) {
+    grpc_linked_error *lerr = (grpc_linked_error *)(error->arena + slot);
+    if (grpc_error_has_clear_grpc_status(lerr->err)) {
       return true;
     }
+    slot = lerr->next;
   }
   return false;
 }
diff --git a/src/core/lib/transport/transport.c b/src/core/lib/transport/transport.c
index 004e748f25..165950e288 100644
--- a/src/core/lib/transport/transport.c
+++ b/src/core/lib/transport/transport.c
@@ -84,6 +84,39 @@ void grpc_stream_unref(grpc_exec_ctx *exec_ctx,
   }
 }
 
+#define STREAM_REF_FROM_SLICE_REF(p)         \
+  ((grpc_stream_refcount *)(((uint8_t *)p) - \
+                            offsetof(grpc_stream_refcount, slice_refcount)))
+
+static void slice_stream_ref(void *p) {
+#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+  grpc_stream_ref(STREAM_REF_FROM_SLICE_REF(p), "slice");
+#else
+  grpc_stream_ref(STREAM_REF_FROM_SLICE_REF(p));
+#endif
+}
+
+static void slice_stream_unref(grpc_exec_ctx *exec_ctx, void *p) {
+#ifdef GRPC_STREAM_REFCOUNT_DEBUG
+  grpc_stream_unref(exec_ctx, STREAM_REF_FROM_SLICE_REF(p), "slice");
+#else
+  grpc_stream_unref(exec_ctx, STREAM_REF_FROM_SLICE_REF(p));
+#endif
+}
+
+grpc_slice grpc_slice_from_stream_owned_buffer(grpc_stream_refcount *refcount,
+                                               void *buffer, size_t length) {
+  slice_stream_ref(&refcount->slice_refcount);
+  return (grpc_slice){.refcount = &refcount->slice_refcount,
+                      .data.refcounted = {.bytes = buffer, .length = length}};
+}
+
+static const grpc_slice_refcount_vtable stream_ref_slice_vtable = {
+    .ref = slice_stream_ref,
+    .unref = slice_stream_unref,
+    .eq = grpc_slice_default_eq_impl,
+    .hash = grpc_slice_default_hash_impl};
+
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
 void grpc_stream_ref_init(grpc_stream_refcount *refcount, int initial_refs,
                           grpc_iomgr_cb_func cb, void *cb_arg,
@@ -95,6 +128,8 @@ void grpc_stream_ref_init(grpc_stream_refcount *refcount, int initial_refs,
 #endif
   gpr_ref_init(&refcount->refs, initial_refs);
   grpc_closure_init(&refcount->destroy, cb, cb_arg, grpc_schedule_on_exec_ctx);
+  refcount->slice_refcount.vtable = &stream_ref_slice_vtable;
+  refcount->slice_refcount.sub_refcount = &refcount->slice_refcount;
 }
 
 static void move64(uint64_t *from, uint64_t *to) {
diff --git a/src/core/lib/transport/transport.h b/src/core/lib/transport/transport.h
index bb23c0225a..cc1c277b35 100644
--- a/src/core/lib/transport/transport.h
+++ b/src/core/lib/transport/transport.h
@@ -64,6 +64,7 @@ typedef struct grpc_stream_refcount {
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
   const char *object_type;
 #endif
+  grpc_slice_refcount slice_refcount;
 } grpc_stream_refcount;
 
 #ifdef GRPC_STREAM_REFCOUNT_DEBUG
@@ -84,6 +85,11 @@ void grpc_stream_unref(grpc_exec_ctx *exec_ctx, grpc_stream_refcount *refcount);
   grpc_stream_ref_init(rc, ir, cb, cb_arg)
 #endif
 
+/* Wrap a buffer that is owned by some stream object into a slice that shares
+   the same refcount */
+grpc_slice grpc_slice_from_stream_owned_buffer(grpc_stream_refcount *refcount,
+                                               void *buffer, size_t length);
+
 typedef struct {
   uint64_t framing_bytes;
   uint64_t data_bytes;
diff --git a/src/core/lib/tsi/test_creds/BUILD b/src/core/lib/tsi/test_creds/BUILD
index dcd6d930a8..5cf04caf17 100644
--- a/src/core/lib/tsi/test_creds/BUILD
+++ b/src/core/lib/tsi/test_creds/BUILD
@@ -27,6 +27,8 @@
 # (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 # OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 
+licenses(["notice"])  # 3-clause BSD
+
 exports_files([
     "ca.pem",
     "server1.key",