[scudo][standalone] Shift some data from dynamic to static

Summary:
Most of our larger data is dynamically allocated (via `map`) but it
became an hindrance with regard to init time, for a cost to benefit
ratio that is not great. So change the `TSD`s, `RegionInfo`, `ByteMap`
to be static.

Additionally, for reclaiming, we used mapped & unmapped a buffer each
time, which is costly. It turns out that we can have a static buffer,
and that there isn't much contention on it.

One of the other things changed here, is that we hard set the number
of TSDs on Android to the maximum number, as there could be a
situation where cores are put to sleep and we could miss some.

Subscribers: mgorny, #sanitizers, llvm-commits

Tags: #sanitizers, #llvm

Differential Revision: https://reviews.llvm.org/D74696

compiler-rt/lib/scudo/standalone/CMakeLists.txt

@@ -88,6 +88,7 @@ set(SCUDO_SOURCES
   flags_parser.cpp
   fuchsia.cpp
   linux.cpp
+  release.cpp
   report.cpp
   string_utils.cpp
   )

compiler-rt/lib/scudo/standalone/bytemap.h

@@ -17,12 +17,10 @@ namespace scudo {
 
 template <uptr Size> class FlatByteMap {
 public:
-  void initLinkerInitialized() {
-    Map = reinterpret_cast<u8 *>(map(nullptr, Size, "scudo:bytemap"));
-  }
-  void init() { initLinkerInitialized(); }
+  void initLinkerInitialized() {}
+  void init() { memset(Map, 0, sizeof(Map)); }
 
-  void unmapTestOnly() { unmap(reinterpret_cast<void *>(Map), Size); }
+  void unmapTestOnly() {}
 
   void set(uptr Index, u8 Value) {
     DCHECK_LT(Index, Size);
@@ -38,7 +36,7 @@ public:
   void enable() {}
 
 private:
-  u8 *Map;
+  u8 Map[Size];
 };
 
 } // namespace scudo

compiler-rt/lib/scudo/standalone/primary32.h

@@ -40,7 +40,8 @@ namespace scudo {
 
 template <class SizeClassMapT, uptr RegionSizeLog,
           s32 MinReleaseToOsIntervalMs = INT32_MIN,
-          s32 MaxReleaseToOsIntervalMs = INT32_MAX> class SizeClassAllocator32 {
+          s32 MaxReleaseToOsIntervalMs = INT32_MAX>
+class SizeClassAllocator32 {
 public:
   typedef SizeClassMapT SizeClassMap;
   // The bytemap can only track UINT8_MAX - 1 classes.
@@ -49,7 +50,8 @@ public:
   static_assert((1UL << RegionSizeLog) >= SizeClassMap::MaxSize, "");
   typedef SizeClassAllocator32<SizeClassMapT, RegionSizeLog,
                                MinReleaseToOsIntervalMs,
-                               MaxReleaseToOsIntervalMs> ThisT;
+                               MaxReleaseToOsIntervalMs>
+      ThisT;
   typedef SizeClassAllocatorLocalCache<ThisT> CacheT;
   typedef typename CacheT::TransferBatch TransferBatch;
   static const bool SupportsMemoryTagging = false;

compiler-rt/lib/scudo/standalone/primary64.h

@@ -46,10 +46,9 @@ template <class SizeClassMapT, uptr RegionSizeLog,
 class SizeClassAllocator64 {
 public:
   typedef SizeClassMapT SizeClassMap;
-  typedef SizeClassAllocator64<SizeClassMap, RegionSizeLog,
-                               MinReleaseToOsIntervalMs,
-                               MaxReleaseToOsIntervalMs,
-                               MaySupportMemoryTagging>
+  typedef SizeClassAllocator64<
+      SizeClassMap, RegionSizeLog, MinReleaseToOsIntervalMs,
+      MaxReleaseToOsIntervalMs, MaySupportMemoryTagging>
       ThisT;
   typedef SizeClassAllocatorLocalCache<ThisT> CacheT;
   typedef typename CacheT::TransferBatch TransferBatch;
@@ -69,11 +68,6 @@ public:
     PrimaryBase = reinterpret_cast<uptr>(
         map(nullptr, PrimarySize, "scudo:primary", MAP_NOACCESS, &Data));
 
-    RegionInfoArray = reinterpret_cast<RegionInfo *>(
-        map(nullptr, sizeof(RegionInfo) * NumClasses, "scudo:regioninfo"));
-    DCHECK_EQ(reinterpret_cast<uptr>(RegionInfoArray) % SCUDO_CACHE_LINE_SIZE,
-              0);
-
     u32 Seed;
     if (UNLIKELY(!getRandom(reinterpret_cast<void *>(&Seed), sizeof(Seed))))
       Seed = static_cast<u32>(getMonotonicTime() ^ (PrimaryBase >> 12));
@@ -106,8 +100,6 @@ public:
 
   void unmapTestOnly() {
     unmap(reinterpret_cast<void *>(PrimaryBase), PrimarySize, UNMAP_ALL, &Data);
-    unmap(reinterpret_cast<void *>(RegionInfoArray),
-          sizeof(RegionInfo) * NumClasses);
   }
 
   TransferBatch *popBatch(CacheT *C, uptr ClassId) {
@@ -156,7 +148,7 @@ public:
     }
   }
 
-  template <typename F> void iterateOverBlocks(F Callback) const {
+  template <typename F> void iterateOverBlocks(F Callback) {
     for (uptr I = 0; I < NumClasses; I++) {
       if (I == SizeClassMap::BatchClassId)
         continue;
@@ -169,7 +161,7 @@ public:
     }
   }
 
-  void getStats(ScopedString *Str) const {
+  void getStats(ScopedString *Str) {
     // TODO(kostyak): get the RSS per region.
     uptr TotalMapped = 0;
     uptr PoppedBlocks = 0;
@@ -252,12 +244,12 @@ private:
   static_assert(sizeof(RegionInfo) % SCUDO_CACHE_LINE_SIZE == 0, "");
 
   uptr PrimaryBase;
-  RegionInfo *RegionInfoArray;
   MapPlatformData Data;
   atomic_s32 ReleaseToOsIntervalMs;
   bool UseMemoryTagging;
+  RegionInfo RegionInfoArray[NumClasses];
 
-  RegionInfo *getRegionInfo(uptr ClassId) const {
+  RegionInfo *getRegionInfo(uptr ClassId) {
     DCHECK_LT(ClassId, NumClasses);
     return &RegionInfoArray[ClassId];
   }
@@ -371,7 +363,7 @@ private:
     return B;
   }
 
-  void getStats(ScopedString *Str, uptr ClassId, uptr Rss) const {
+  void getStats(ScopedString *Str, uptr ClassId, uptr Rss) {
     RegionInfo *Region = getRegionInfo(ClassId);
     if (Region->MappedUser == 0)
       return;

compiler-rt/lib/scudo/standalone/release.cpp

@@ -0,0 +1,16 @@
+//===-- release.cpp ---------------------------------------------*- C++ -*-===//
+//
+// Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions.
+// See https://llvm.org/LICENSE.txt for license information.
+// SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception
+//
+//===----------------------------------------------------------------------===//
+
+#include "release.h"
+
+namespace scudo {
+
+HybridMutex PackedCounterArray::Mutex = {};
+uptr PackedCounterArray::StaticBuffer[1024];
+
+} // namespace scudo

compiler-rt/lib/scudo/standalone/release.h

@@ -11,6 +11,7 @@
 
 #include "common.h"
 #include "list.h"
+#include "mutex.h"
 
 namespace scudo {
 
@@ -39,11 +40,13 @@ private:
 };
 
 // A packed array of Counters. Each counter occupies 2^N bits, enough to store
-// counter's MaxValue. Ctor will try to allocate the required Buffer via map()
-// and the caller is expected to check whether the initialization was successful
-// by checking isAllocated() result. For the performance sake, none of the
-// accessors check the validity of the arguments, It is assumed that Index is
-// always in [0, N) range and the value is not incremented past MaxValue.
+// counter's MaxValue. Ctor will try to use a static buffer first, and if that
+// fails (the buffer is too small or already locked), will allocate the
+// required Buffer via map(). The caller is expected to check whether the
+// initialization was successful by checking isAllocated() result. For
+// performance sake, none of the accessors check the validity of the arguments,
+// It is assumed that Index is always in [0, N) range and the value is not
+// incremented past MaxValue.
 class PackedCounterArray {
 public:
   PackedCounterArray(uptr NumCounters, uptr MaxValue) : N(NumCounters) {
@@ -66,11 +69,20 @@ public:
     BufferSize = (roundUpTo(N, static_cast<uptr>(1U) << PackingRatioLog) >>
                   PackingRatioLog) *
                  sizeof(*Buffer);
-    Buffer = reinterpret_cast<uptr *>(
-        map(nullptr, BufferSize, "scudo:counters", MAP_ALLOWNOMEM));
+    if (BufferSize <= StaticBufferSize && Mutex.tryLock()) {
+      Buffer = &StaticBuffer[0];
+      memset(Buffer, 0, BufferSize);
+    } else {
+      Buffer = reinterpret_cast<uptr *>(
+          map(nullptr, BufferSize, "scudo:counters", MAP_ALLOWNOMEM));
+    }
   }
   ~PackedCounterArray() {
-    if (isAllocated())
+    if (!isAllocated())
+      return;
+    if (Buffer == &StaticBuffer[0])
+      Mutex.unlock();
+    else
       unmap(reinterpret_cast<void *>(Buffer), BufferSize);
   }
 
@@ -110,6 +122,10 @@ private:
 
   uptr BufferSize;
   uptr *Buffer;
+
+  static HybridMutex Mutex;
+  static const uptr StaticBufferSize = 1024U;
+  static uptr StaticBuffer[StaticBufferSize];
 };
 
 template <class ReleaseRecorderT> class FreePagesRangeTracker {

compiler-rt/lib/scudo/standalone/tsd_exclusive.h

@@ -25,9 +25,7 @@ template <class Allocator> struct TSDRegistryExT {
   void initLinkerInitialized(Allocator *Instance) {
     Instance->initLinkerInitialized();
     CHECK_EQ(pthread_key_create(&PThreadKey, teardownThread<Allocator>), 0);
-    FallbackTSD = reinterpret_cast<TSD<Allocator> *>(
-        map(nullptr, sizeof(TSD<Allocator>), "scudo:tsd"));
-    FallbackTSD->initLinkerInitialized(Instance);
+    FallbackTSD.initLinkerInitialized(Instance);
     Initialized = true;
   }
   void init(Allocator *Instance) {
@@ -35,9 +33,7 @@ template <class Allocator> struct TSDRegistryExT {
     initLinkerInitialized(Instance);
   }
 
-  void unmapTestOnly() {
-    unmap(reinterpret_cast<void *>(FallbackTSD), sizeof(TSD<Allocator>));
-  }
+  void unmapTestOnly() {}
 
   ALWAYS_INLINE void initThreadMaybe(Allocator *Instance, bool MinimalInit) {
     if (LIKELY(State != ThreadState::NotInitialized))
@@ -51,23 +47,22 @@ template <class Allocator> struct TSDRegistryExT {
       *UnlockRequired = false;
       return &ThreadTSD;
     }
-    DCHECK(FallbackTSD);
-    FallbackTSD->lock();
+    FallbackTSD.lock();
     *UnlockRequired = true;
-    return FallbackTSD;
+    return &FallbackTSD;
   }
 
   // To disable the exclusive TSD registry, we effectively lock the fallback TSD
   // and force all threads to attempt to use it instead of their local one.
   void disable() {
     Mutex.lock();
-    FallbackTSD->lock();
+    FallbackTSD.lock();
     atomic_store(&Disabled, 1U, memory_order_release);
   }
 
   void enable() {
     atomic_store(&Disabled, 0U, memory_order_release);
-    FallbackTSD->unlock();
+    FallbackTSD.unlock();
     Mutex.unlock();
   }
 
@@ -96,7 +91,7 @@ private:
   pthread_key_t PThreadKey;
   bool Initialized;
   atomic_u8 Disabled;
-  TSD<Allocator> *FallbackTSD;
+  TSD<Allocator> FallbackTSD;
   HybridMutex Mutex;
   static THREADLOCAL ThreadState State;
   static THREADLOCAL TSD<Allocator> ThreadTSD;

compiler-rt/lib/scudo/standalone/tsd_shared.h

@@ -19,10 +19,9 @@ template <class Allocator, u32 MaxTSDCount> struct TSDRegistrySharedT {
     Instance->initLinkerInitialized();
     CHECK_EQ(pthread_key_create(&PThreadKey, nullptr), 0); // For non-TLS
     const u32 NumberOfCPUs = getNumberOfCPUs();
-    NumberOfTSDs =
-        (NumberOfCPUs == 0) ? MaxTSDCount : Min(NumberOfCPUs, MaxTSDCount);
-    TSDs = reinterpret_cast<TSD<Allocator> *>(
-        map(nullptr, sizeof(TSD<Allocator>) * NumberOfTSDs, "scudo:tsd"));
+    NumberOfTSDs = (SCUDO_ANDROID || NumberOfCPUs == 0)
+                       ? MaxTSDCount
+                       : Min(NumberOfCPUs, MaxTSDCount);
     for (u32 I = 0; I < NumberOfTSDs; I++)
       TSDs[I].initLinkerInitialized(Instance);
     // Compute all the coprimes of NumberOfTSDs. This will be used to walk the
@@ -48,8 +47,6 @@ template <class Allocator, u32 MaxTSDCount> struct TSDRegistrySharedT {
   }
 
   void unmapTestOnly() {
-    unmap(reinterpret_cast<void *>(TSDs),
-          sizeof(TSD<Allocator>) * NumberOfTSDs);
     setCurrentTSD(nullptr);
     pthread_key_delete(PThreadKey);
   }
@@ -162,11 +159,11 @@ private:
   pthread_key_t PThreadKey;
   atomic_u32 CurrentIndex;
   u32 NumberOfTSDs;
-  TSD<Allocator> *TSDs;
   u32 NumberOfCoPrimes;
   u32 CoPrimes[MaxTSDCount];
   bool Initialized;
   HybridMutex Mutex;
+  TSD<Allocator> TSDs[MaxTSDCount];
 #if SCUDO_LINUX && !_BIONIC
   static THREADLOCAL TSD<Allocator> *ThreadTSD;
 #endif

compiler-rt/lib/scudo/standalone/wrappers_c.inc

@@ -195,7 +195,7 @@ INTERFACE WEAK int SCUDO_PREFIX(malloc_info)(UNUSED int options, FILE *stream) {
       decltype(SCUDO_ALLOCATOR)::PrimaryT::SizeClassMap::MaxSize;
   auto *sizes = static_cast<scudo::uptr *>(
       SCUDO_PREFIX(calloc)(max_size, sizeof(scudo::uptr)));
-  auto callback = [](uintptr_t, size_t size, void* arg) {
+  auto callback = [](uintptr_t, size_t size, void *arg) {
     auto *sizes = reinterpret_cast<scudo::uptr *>(arg);
     if (size < max_size)
       sizes[size]++;