perf_hooks: add NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP constant

V8's Minor Mark-Sweep collector, enabled with the --minor-ms flag
(available since Node.js 22), reports garbage collection performance
entries with kind kGCTypeMinorMarkSweep (value 2). perf_hooks exposed
constants for every other GC kind (major, minor, incremental, weakcb)
but not this one, so consumers inspecting performanceEntry.detail.kind
had no constant to compare against and saw an unmapped value.

Expose it as perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP,
mirroring the existing v8::GCType mappings, and document it alongside
the other GC kinds.

Signed-off-by: Attila Szegedi <attila.szegedi@datadoghq.com>

Author: szegedi

doc/api/perf_hooks.md

@@ -643,6 +643,7 @@ The value may be one of:
 
 * `perf_hooks.constants.NODE_PERFORMANCE_GC_MAJOR`
 * `perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR`
+* `perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP`
 * `perf_hooks.constants.NODE_PERFORMANCE_GC_INCREMENTAL`
 * `perf_hooks.constants.NODE_PERFORMANCE_GC_WEAKCB`
 
@@ -654,6 +655,7 @@ When `performanceEntry.type` is equal to `'gc'`, the
 * `kind` {number} One of:
   * `perf_hooks.constants.NODE_PERFORMANCE_GC_MAJOR`
   * `perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR`
+  * `perf_hooks.constants.NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP`
   * `perf_hooks.constants.NODE_PERFORMANCE_GC_INCREMENTAL`
   * `perf_hooks.constants.NODE_PERFORMANCE_GC_WEAKCB`
 * `flags` {number} One of:

src/node_perf.cc

@@ -365,6 +365,7 @@ void CreatePerContextProperties(Local<Object> target,
 
   NODE_DEFINE_CONSTANT(constants, NODE_PERFORMANCE_GC_MAJOR);
   NODE_DEFINE_CONSTANT(constants, NODE_PERFORMANCE_GC_MINOR);
+  NODE_DEFINE_CONSTANT(constants, NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP);
   NODE_DEFINE_CONSTANT(constants, NODE_PERFORMANCE_GC_INCREMENTAL);
   NODE_DEFINE_CONSTANT(constants, NODE_PERFORMANCE_GC_WEAKCB);
 

src/node_perf.h

@@ -63,6 +63,7 @@ inline PerformanceEntryType ToPerformanceEntryTypeEnum(
 enum PerformanceGCKind {
   NODE_PERFORMANCE_GC_MAJOR = v8::GCType::kGCTypeMarkSweepCompact,
   NODE_PERFORMANCE_GC_MINOR = v8::GCType::kGCTypeScavenge,
+  NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP = v8::GCType::kGCTypeMinorMarkSweep,
   NODE_PERFORMANCE_GC_INCREMENTAL = v8::GCType::kGCTypeIncrementalMarking,
   NODE_PERFORMANCE_GC_WEAKCB = v8::GCType::kGCTypeProcessWeakCallbacks
 };

test/parallel/test-performance-gc-minor-ms.js

@@ -0,0 +1,33 @@
+// Flags: --expose-gc --no-warnings --minor-ms
+'use strict';
+
+// When V8's Minor Mark-Sweep collector is enabled (--minor-ms), minor garbage
+// collections are reported with kind NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP
+// rather than NODE_PERFORMANCE_GC_MINOR.
+
+const common = require('../common');
+const assert = require('assert');
+const {
+  PerformanceObserver,
+  constants
+} = require('perf_hooks');
+
+const {
+  NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP,
+  NODE_PERFORMANCE_GC_FLAGS_FORCED
+} = constants;
+
+const obs = new PerformanceObserver(common.mustCallAtLeast((list) => {
+  const entry = list.getEntries()[0];
+  assert(entry);
+  assert.strictEqual(entry.name, 'gc');
+  assert.strictEqual(entry.entryType, 'gc');
+  assert.strictEqual(entry.detail.kind, NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP);
+  assert.strictEqual(entry.detail.flags, NODE_PERFORMANCE_GC_FLAGS_FORCED);
+  obs.disconnect();
+}));
+obs.observe({ entryTypes: ['gc'] });
+
+globalThis.gc({ type: 'minor' });
+// Keep the event loop alive to witness the GC async callback happen.
+setImmediate(() => setImmediate(() => 0));

test/parallel/test-performance-gc.js

@@ -11,6 +11,7 @@ const {
 const {
   NODE_PERFORMANCE_GC_MAJOR,
   NODE_PERFORMANCE_GC_MINOR,
+  NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP,
   NODE_PERFORMANCE_GC_INCREMENTAL,
   NODE_PERFORMANCE_GC_WEAKCB,
   NODE_PERFORMANCE_GC_FLAGS_FORCED
@@ -19,6 +20,7 @@ const {
 const kinds = [
   NODE_PERFORMANCE_GC_MAJOR,
   NODE_PERFORMANCE_GC_MINOR,
+  NODE_PERFORMANCE_GC_MINOR_MARK_SWEEP,
   NODE_PERFORMANCE_GC_INCREMENTAL,
   NODE_PERFORMANCE_GC_WEAKCB,
 ];