1 //===-- stats.h -------------------------------------------------*- C++ -*-===// 2 // 3 // Part of the LLVM Project, under the Apache License v2.0 with LLVM Exceptions. 4 // See https://llvm.org/LICENSE.txt for license information. 5 // SPDX-License-Identifier: Apache-2.0 WITH LLVM-exception 6 // 7 //===----------------------------------------------------------------------===// 8 9 #ifndef SCUDO_STATS_H_ 10 #define SCUDO_STATS_H_ 11 12 #include "atomic_helpers.h" 13 #include "list.h" 14 #include "mutex.h" 15 16 #include <string.h> 17 18 namespace scudo { 19 20 // Memory allocator statistics 21 enum StatType { StatAllocated, StatFree, StatMapped, StatCount }; 22 23 typedef uptr StatCounters[StatCount]; 24 25 // Per-thread stats, live in per-thread cache. We use atomics so that the 26 // numbers themselves are consistent. But we don't use atomic_{add|sub} or a 27 // lock, because those are expensive operations , and we only care for the stats 28 // to be "somewhat" correct: eg. if we call GlobalStats::get while a thread is 29 // LocalStats::add'ing, this is OK, we will still get a meaningful number. 30 class LocalStats { 31 public: 32 void initLinkerInitialized() {} 33 void init() { memset(this, 0, sizeof(*this)); } 34 35 void add(StatType I, uptr V) { 36 V += atomic_load_relaxed(&StatsArray[I]); 37 atomic_store_relaxed(&StatsArray[I], V); 38 } 39 40 void sub(StatType I, uptr V) { 41 V = atomic_load_relaxed(&StatsArray[I]) - V; 42 atomic_store_relaxed(&StatsArray[I], V); 43 } 44 45 void set(StatType I, uptr V) { atomic_store_relaxed(&StatsArray[I], V); } 46 47 uptr get(StatType I) const { return atomic_load_relaxed(&StatsArray[I]); } 48 49 LocalStats *Next; 50 LocalStats *Prev; 51 52 private: 53 atomic_uptr StatsArray[StatCount]; 54 }; 55 56 // Global stats, used for aggregation and querying. 57 class GlobalStats : public LocalStats { 58 public: 59 void initLinkerInitialized() {} 60 void init() { 61 LocalStats::init(); 62 Mutex.init(); 63 StatsList = {}; 64 initLinkerInitialized(); 65 } 66 67 void link(LocalStats *S) { 68 ScopedLock L(Mutex); 69 StatsList.push_back(S); 70 } 71 72 void unlink(LocalStats *S) { 73 ScopedLock L(Mutex); 74 StatsList.remove(S); 75 for (uptr I = 0; I < StatCount; I++) 76 add(static_cast<StatType>(I), S->get(static_cast<StatType>(I))); 77 } 78 79 void get(uptr *S) const { 80 ScopedLock L(Mutex); 81 for (uptr I = 0; I < StatCount; I++) 82 S[I] = LocalStats::get(static_cast<StatType>(I)); 83 for (const auto &Stats : StatsList) { 84 for (uptr I = 0; I < StatCount; I++) 85 S[I] += Stats.get(static_cast<StatType>(I)); 86 } 87 // All stats must be non-negative. 88 for (uptr I = 0; I < StatCount; I++) 89 S[I] = static_cast<sptr>(S[I]) >= 0 ? S[I] : 0; 90 } 91 92 void disable() { Mutex.lock(); } 93 void enable() { Mutex.unlock(); } 94 95 private: 96 mutable HybridMutex Mutex; 97 DoublyLinkedList<LocalStats> StatsList; 98 }; 99 100 } // namespace scudo 101 102 #endif // SCUDO_STATS_H_ 103