Fix GC stress test.

kotlin-native/backend.native/tests/build.gradle

@@ -2970,6 +2970,12 @@ standaloneTest("leakMemoryWithTestRunner") {
 }
 
 standaloneTest("stress_gc_allocations") {
+    // TODO: Support obtaining peak RSS on more platforms.
+    enabled = (project.testTarget != "wasm32") &&
+        (project.testTarget != "watchos_arm32") &&
+        (project.testTarget != "watchos_arm64") &&
+        (project.testTarget != "watchos_x86") &&
+        (project.testTarget != "watchos_x64")
     source = "runtime/memory/stress_gc_allocations.kt"
     flags = ['-tr', '-Xopt-in=kotlin.native.internal.InternalForKotlinNative']
 }

kotlin-native/backend.native/tests/runtime/memory/stress_gc_allocations.kt

@@ -8,10 +8,11 @@ import kotlin.native.concurrent.*
 import kotlin.native.internal.MemoryUsageInfo
 
 object Blackhole {
-    private val hole = AtomicLong(0)
+    // On MIPS `AtomicLong` does not support `addAndGet`. TODO: Fix it.
+    private val hole = AtomicInt(0)
 
     fun consume(value: Any) {
-        hole.addAndGet(value.hashCode())
+        hole.addAndGet(value.hashCode().toInt())
     }
 
     fun discharge() {
@@ -50,8 +51,8 @@ fun test() {
     val value: Byte = 42
     // Try to make sure each page is written
     val stride = 4096
-    // Limit memory usage at ~200MiB
-    val rssDiffLimit: Long = 200_000_000
+    // Limit memory usage at ~500MiB. This limit was exercised by -Xallocator=mimalloc and legacy MM.
+    val rssDiffLimit: Long = 500_000_000
     // Trigger GC after ~100MiB are allocated
     val retainLimit: Long = 100_000_000
     val progressReportsCount = 100