more Ci fixes

.github/workflows/platform.yml

@@ -85,6 +85,12 @@ jobs:
       - name: Unload host AppArmor profiles
         run: sudo aa-teardown || true
 
+      # Some tests (e.g. sh6bench) keep tens of thousands of allocations live at
+      # once and some allocators (e.g. hardened_malloc) map guard pages per
+      # large allocation, so they hit vm.max_map_count. Increase to make them pass.
+      - name: Raise vm.max_map_count for the benchmarks
+        run: sudo sysctl -w vm.max_map_count=1048576
+
       - name: Build allocator and run benchmarks in Docker
         id: docker_build
         uses: docker/build-push-action@v7

README.md

@@ -81,6 +81,18 @@ sudo aa-teardown
 GitHub CI runners have this profile, so the CI workflow unloads the host
 profiles before building.
 
+**`sh6bench` reports "Out of memory" for some allocators although the machine
+has plenty of memory?**
+Some allocators (hardened_malloc `hm` for example) map guard pages around their
+allocations, so every live allocation costs at least one extra kernel mapping,
+and `sh6bench` keeps tens of thousands of them alive at once: with 16 threads it
+measures over 140000 mappings, more than the default `vm.max_map_count` of
+65530. Once the limit is reached, `mprotect` fails and `malloc` returns null.
+Raise the limit:
+```
+sudo sysctl -w vm.max_map_count=1048576
+```
+
 ## Current Allocators
 
 Supported allocators are as follow, see

build-bench-env.sh

@@ -649,16 +649,24 @@ fi
 
 if test "$setup_tcg" = "1"; then
   checkout tcg $version_tcg https://github.com/google/tcmalloc
+  # tcmalloc only builds static libraries, so add a target for the shared
+  # library that bench.sh preloads
+  set +e
+  patch -p1 -N -r- < ../../patches/tcg.patch
+  set -e
   if command -v bazelisk > /dev/null; then
-    USE_BAZEL_VERSION=$version_bazel bazelisk build -c opt tcmalloc
+    USE_BAZEL_VERSION=$version_bazel bazelisk build -c opt tcmalloc //tcmalloc:libtcmalloc.so
   else
-    bazel build -c opt tcmalloc
+    bazel build -c opt tcmalloc //tcmalloc:libtcmalloc.so
   fi
   popd
 fi
 
 if test "$setup_hd" = "1"; then
   checkout hd $version_hd https://github.com/emeryberger/Hoard
+  set +e
+  patch -p1 -N -r- < ../../patches/hoard.patch
+  set -e
   cd src
   if [ "`uname -m -s`" = "Darwin x86_64" ] ; then
     sed -i_orig 's/-arch arm64/ /g' GNUmakefile   # fix the makefile    

patches/hoard.patch

@@ -0,0 +1,17 @@
+diff --git a/src/source/libhoard.cpp b/src/source/libhoard.cpp
+index 0f7567a..0b36a79 100644
+--- a/src/source/libhoard.cpp
++++ b/src/source/libhoard.cpp
+@@ -163,3 +163,12 @@ extern "C" {
+ // include gnuwrapper here to aid inlining of xxmalloc + friends
+ #include "wrappers/gnuwrapper.cpp"
+ #endif
++
++
++// Heap-Layers' macwrapper.cpp defines these as weak defaults; its linux
++// wrapper.cpp calls them but libhoard.cpp did not define them, so libhoard.so
++// ended up with undefined symbols.
++extern "C" {
++  __attribute__((weak)) void xxfree_sized (void * ptr, size_t) { xxfree(ptr); }
++  __attribute__((weak)) void xxfree_aligned_sized (void * ptr, size_t, size_t) { xxfree(ptr); }
++}

patches/tcg.patch

@@ -0,0 +1,14 @@
+diff --git a/tcmalloc/BUILD b/tcmalloc/BUILD
+index 47b0f065..cfb1570a 100644
+--- a/tcmalloc/BUILD
++++ b/tcmalloc/BUILD
+@@ -1610,3 +1610,9 @@ cc_library(
+     ],
+     deps = ["@com_google_absl//absl/base:core_headers"],
+ )
++
++cc_binary(
++    name = "libtcmalloc.so",
++    linkshared = 1,
++    deps = [":tcmalloc"],
++)