From f9e56609401e505c835796726eff35e650810fff Mon Sep 17 00:00:00 2001
From: Stefan Boberg <stefan.boberg@epicgames.com>
Date: Sun, 22 Mar 2026 10:57:12 +0100
Subject: Upgrade mimalloc to v2.2.7 and log active memory allocator (#876)
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- Upgrade mimalloc from v2.1.2 to v2.2.7. Note that mimalloc is no longer the default allocator so this only impacts users who somehow opt into mimalloc via `--malloc=mimalloc` or compile with different defaults
- Add all available mimalloc versions (1.6.7–3.2.8) to the package definition for testing
- Log the active memory allocator (with version where available) at server startup
- Annotate vendored rpmalloc with its source commit and version

## Notable changes in mimalloc 2.1.2 → 2.2.7

- **Memory release fix** (2.2.4): fix case where OS memory was not always fully released
- **Race condition fix** (2.2.6): fixed rare race condition and potential buffer overflow in debug statistics
- **Windows arm64 support** (2.1.9)
- **Guarded build** (2.1.9): new build mode that places OS guard pages behind objects to catch buffer overflows
- **THP awareness** (2.2.6): auto-detects transparent huge pages and adjusts purge size to avoid fragmentation
- **Faster TLS access on Windows** (2.2.6)
- **Improved calloc and aligned allocation performance** (2.2.6)
- **New diagnostic APIs** (2.2.2): `mi_options_print`, `mi_arenas_print`, `mi_stat_get` / `mi_stat_get_json`
- **macOS**: use `MADV_FREE_REUSABLE` for better memory behavior (2.2.4)
- **Build fixes**: Android, Xbox, musl, mingw, arm32, Debian 32-bit, non-BMI1 x64 systems

## Allocator logging

Added `FMalloc::GetName()` pure virtual so the server logs which allocator is active at startup:
```
zenserver - memory allocator: mimalloc 2.2.7
```

Allocator names include version where available:
- `mimalloc 2.2.7` (runtime version via `mi_version()`)
- `rpmalloc 1.5.0-dev.20250810` (ad-hoc version from vendored develop branch commit)
- `ansi`, `stomp` (no version info available)

## Test plan

- [x] Builds successfully on Windows (release)
- [x] Verify server startup log shows allocator name
- [x] Test with `--malloc=mimalloc` (default) and `--malloc=rpmalloc`
- [x] Run test suites to check for regressions
---
 src/zencore/memory/mallocansi.cpp | 6 ++++++
 1 file changed, 6 insertions(+)

(limited to 'src/zencore/memory/mallocansi.cpp')

diff --git a/src/zencore/memory/mallocansi.cpp b/src/zencore/memory/mallocansi.cpp
index 9c3936172..e9465b46b 100644
--- a/src/zencore/memory/mallocansi.cpp
+++ b/src/zencore/memory/mallocansi.cpp
@@ -248,4 +248,10 @@ FMallocAnsi::GetAllocationSize(void* Original, size_t& SizeOut)
 #endif
 }
 
+const char*
+FMallocAnsi::GetName() const
+{
+	return "ansi";
+}
+
 }  // namespace zen
-- 
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