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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-exception6//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#include "thread_annotations.h"16 17#include <string.h>18 19namespace scudo {20 21// Memory allocator statistics22enum StatType { StatAllocated, StatFree, StatMapped, StatCount };23 24typedef uptr StatCounters[StatCount];25 26// Per-thread stats, live in per-thread cache. We use atomics so that the27// numbers themselves are consistent. But we don't use atomic_{add|sub} or a28// lock, because those are expensive operations , and we only care for the stats29// to be "somewhat" correct: eg. if we call GlobalStats::get while a thread is30// LocalStats::add'ing, this is OK, we will still get a meaningful number.31class LocalStats {32public:33 void init() {34 for (uptr I = 0; I < StatCount; I++)35 DCHECK_EQ(get(static_cast<StatType>(I)), 0U);36 }37 38 void add(StatType I, uptr V) {39 V += atomic_load_relaxed(&StatsArray[I]);40 atomic_store_relaxed(&StatsArray[I], V);41 }42 43 void sub(StatType I, uptr V) {44 V = atomic_load_relaxed(&StatsArray[I]) - V;45 atomic_store_relaxed(&StatsArray[I], V);46 }47 48 void set(StatType I, uptr V) { atomic_store_relaxed(&StatsArray[I], V); }49 50 uptr get(StatType I) const { return atomic_load_relaxed(&StatsArray[I]); }51 52 LocalStats *Next = nullptr;53 LocalStats *Prev = nullptr;54 55private:56 atomic_uptr StatsArray[StatCount] = {};57};58 59// Global stats, used for aggregation and querying.60class GlobalStats : public LocalStats {61public:62 void init() { LocalStats::init(); }63 64 void link(LocalStats *S) EXCLUDES(Mutex) {65 ScopedLock L(Mutex);66 StatsList.push_back(S);67 }68 69 void unlink(LocalStats *S) EXCLUDES(Mutex) {70 ScopedLock L(Mutex);71 StatsList.remove(S);72 for (uptr I = 0; I < StatCount; I++)73 add(static_cast<StatType>(I), S->get(static_cast<StatType>(I)));74 }75 76 void get(uptr *S) const EXCLUDES(Mutex) {77 ScopedLock L(Mutex);78 for (uptr I = 0; I < StatCount; I++)79 S[I] = LocalStats::get(static_cast<StatType>(I));80 for (const auto &Stats : StatsList) {81 for (uptr I = 0; I < StatCount; I++)82 S[I] += Stats.get(static_cast<StatType>(I));83 }84 // All stats must be non-negative.85 for (uptr I = 0; I < StatCount; I++)86 S[I] = static_cast<sptr>(S[I]) >= 0 ? S[I] : 0;87 }88 89 void lock() ACQUIRE(Mutex) { Mutex.lock(); }90 void unlock() RELEASE(Mutex) { Mutex.unlock(); }91 92 void disable() ACQUIRE(Mutex) { lock(); }93 void enable() RELEASE(Mutex) { unlock(); }94 95private:96 mutable HybridMutex Mutex;97 DoublyLinkedList<LocalStats> StatsList GUARDED_BY(Mutex);98};99 100} // namespace scudo101 102#endif // SCUDO_STATS_H_103