[resource_quota] Remove periodic resource quota experiment (#31670)

bazel/experiments.bzl

@@ -60,15 +60,6 @@ EXPERIMENTS = {
         "flow_control_test": [
             "tcp_read_chunks",
         ],
-        "hpack_test": [
-            "periodic_resource_quota_reclamation",
-        ],
-        "promise_test": [
-            "periodic_resource_quota_reclamation",
-        ],
-        "resource_quota_test": [
-            "periodic_resource_quota_reclamation",
-        ],
     },
     "opt": {
     },

src/core/lib/experiments/experiments.cc

@@ -37,8 +37,6 @@ const char* const description_flow_control_fixes =
     "Various fixes for flow control, max frame size setting.";
 const char* const description_memory_pressure_controller =
     "New memory pressure controller";
-const char* const description_periodic_resource_quota_reclamation =
-    "Periodically return memory to the resource quota";
 const char* const description_unconstrained_max_quota_buffer_size =
     "Discard the cap on the max free pool size for one memory allocator";
 const char* const description_new_hpack_huffman_decoder =
@@ -70,8 +68,6 @@ const ExperimentMetadata g_experiment_metadata[] = {
     {"flow_control_fixes", description_flow_control_fixes, false},
     {"memory_pressure_controller", description_memory_pressure_controller,
      false},
-    {"periodic_resource_quota_reclamation",
-     description_periodic_resource_quota_reclamation, true},
     {"unconstrained_max_quota_buffer_size",
      description_unconstrained_max_quota_buffer_size, false},
     {"new_hpack_huffman_decoder", description_new_hpack_huffman_decoder,

src/core/lib/experiments/experiments.h

@@ -33,20 +33,17 @@ inline bool IsFlowControlFixesEnabled() { return IsExperimentEnabled(4); }
 inline bool IsMemoryPressureControllerEnabled() {
   return IsExperimentEnabled(5);
 }
-inline bool IsPeriodicResourceQuotaReclamationEnabled() {
-  return IsExperimentEnabled(6);
-}
 inline bool IsUnconstrainedMaxQuotaBufferSizeEnabled() {
-  return IsExperimentEnabled(7);
+  return IsExperimentEnabled(6);
 }
-inline bool IsNewHpackHuffmanDecoderEnabled() { return IsExperimentEnabled(8); }
-inline bool IsEventEngineClientEnabled() { return IsExperimentEnabled(9); }
-inline bool IsMonitoringExperimentEnabled() { return IsExperimentEnabled(10); }
+inline bool IsNewHpackHuffmanDecoderEnabled() { return IsExperimentEnabled(7); }
+inline bool IsEventEngineClientEnabled() { return IsExperimentEnabled(8); }
+inline bool IsMonitoringExperimentEnabled() { return IsExperimentEnabled(9); }
 inline bool IsPromiseBasedClientCallEnabled() {
-  return IsExperimentEnabled(11);
+  return IsExperimentEnabled(10);
 }
 inline bool IsPosixEventEngineEnablePollingEnabled() {
-  return IsExperimentEnabled(12);
+  return IsExperimentEnabled(11);
 }
 
 struct ExperimentMetadata {
@@ -55,7 +52,7 @@ struct ExperimentMetadata {
   bool default_value;
 };
 
-constexpr const size_t kNumExperiments = 13;
+constexpr const size_t kNumExperiments = 12;
 extern const ExperimentMetadata g_experiment_metadata[kNumExperiments];
 
 }  // namespace grpc_core

src/core/lib/experiments/experiments.yaml

@@ -67,7 +67,7 @@
     on the peer's memory pressure which is reflected in its max http2 frame
     size.
   default: false
-  expiry: 2022/11/01
+  expiry: 2023/01/01
   owner: vigneshbabu@google.com
   test_tags: ["flow_control_test"]
 - name: flow_control_fixes
@@ -84,13 +84,6 @@
   expiry: 2023/01/01
   owner: ctiller@google.com
   test_tags: [resource_quota_test]
-- name: periodic_resource_quota_reclamation
-  description:
-    Periodically return memory to the resource quota
-  default: true
-  expiry: 2023/04/01
-  owner: ctiller@google.com
-  test_tags: [resource_quota_test, promise_test, hpack_test]
 - name: unconstrained_max_quota_buffer_size
   description:
     Discard the cap on the max free pool size for one memory allocator

src/core/lib/resource_quota/memory_quota.cc

@@ -253,9 +253,7 @@ void GrpcMemoryAllocatorImpl::MaybeDonateBack() {
         free > kMaxQuotaBufferSize / 2) {
       ret = std::max(ret, free - kMaxQuotaBufferSize / 2);
     }
-    if (IsPeriodicResourceQuotaReclamationEnabled()) {
-      ret = std::max(ret, free > 8192 ? free / 2 : free);
-    }
+    ret = std::max(ret, free > 8192 ? free / 2 : free);
     const size_t new_free = free - ret;
     if (free_bytes_.compare_exchange_weak(free, new_free,
                                           std::memory_order_acq_rel,

src/core/lib/resource_quota/memory_quota.h

@@ -367,8 +367,7 @@ class GrpcMemoryAllocatorImpl final : public EventEngineMemoryAllocatorImpl {
     size_t prev_free = free_bytes_.fetch_add(n, std::memory_order_release);
     if ((!IsUnconstrainedMaxQuotaBufferSizeEnabled() &&
          prev_free + n > kMaxQuotaBufferSize) ||
-        (IsPeriodicResourceQuotaReclamationEnabled() &&
-         donate_back_.Tick([](Duration) {}))) {
+        donate_back_.Tick([](Duration) {})) {
       // Try to immediately return some free'ed memory back to the total quota.
       MaybeDonateBack();
     }