[compiler-rt] [scudo] Secondary release to OS uses LRU to scan. (PR #163691)

[via llvm-commits]

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@@ -503,3 +508,83 @@ TEST(ScudoSecondaryTest, AllocatorCacheOptions) {
       Info.Cache->setOption(scudo::Option::MaxCacheEntrySize, 1UL << 20));
   EXPECT_TRUE(Info.Cache->canCache(1UL << 16));
 }
+
+TEST(ScudoSecondaryTest, ReleaseOlderThanAllEntries) {
+  CacheInfoType<TestCacheConfig> Info;
+  using CacheConfig = CacheInfoType<TestCacheConfig>::CacheConfig;
+
+  Info.Cache->releaseOlderThanTestOnly(UINT64_MAX);
+
+  Info.fillCacheWithSameSizeBlocks(CacheConfig::getDefaultMaxEntriesCount(),
+                                   1024);
+  for (size_t I = 0; I < Info.MemMaps.size(); I++) {
+    // Set the first u32 value to a non-zero value.
+    *reinterpret_cast<scudo::u32 *>(Info.MemMaps[I].getBase()) = 10;
+  }
+
+  Info.Cache->releaseOlderThanTestOnly(UINT64_MAX);
+
+  EXPECT_EQ(Info.MemMaps.size(), CacheConfig::getDefaultMaxEntriesCount());
+  for (size_t I = 0; I < Info.MemMaps.size(); I++) {
+    // All released maps will now be zero.
+    EXPECT_EQ(*reinterpret_cast<scudo::u32 *>(Info.MemMaps[I].getBase()), 0U);
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ChiaHungDuan wrote:

Got it!

https://github.com/llvm/llvm-project/pull/163691