From 26a029d407be480d791972afb5975cf62c9360a6 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Fri, 19 Apr 2024 02:47:55 +0200 Subject: Adding upstream version 124.0.1. Signed-off-by: Daniel Baumann --- .../public/ProfileBufferChunkManager.h | 134 +++++++++++++++++++++ 1 file changed, 134 insertions(+) create mode 100644 mozglue/baseprofiler/public/ProfileBufferChunkManager.h (limited to 'mozglue/baseprofiler/public/ProfileBufferChunkManager.h') diff --git a/mozglue/baseprofiler/public/ProfileBufferChunkManager.h b/mozglue/baseprofiler/public/ProfileBufferChunkManager.h new file mode 100644 index 0000000000..e7f12bf21f --- /dev/null +++ b/mozglue/baseprofiler/public/ProfileBufferChunkManager.h @@ -0,0 +1,134 @@ +/* -*- Mode: C++; tab-width: 2; indent-tabs-mode: nil; c-basic-offset: 2 -*- */ +/* vim: set ts=8 sts=2 et sw=2 tw=80: */ +/* This Source Code Form is subject to the terms of the Mozilla Public + * License, v. 2.0. If a copy of the MPL was not distributed with this + * file, You can obtain one at http://mozilla.org/MPL/2.0/. */ + +#ifndef ProfileBufferChunkManager_h +#define ProfileBufferChunkManager_h + +#include "mozilla/ProfileBufferChunk.h" +#include "mozilla/ScopeExit.h" + +#include + +namespace mozilla { + +// Manages the ProfileBufferChunks for this process. +// The main user of this class is the buffer that needs chunks to store its +// data. +// The main ProfileBufferChunks responsibilities are: +// - It can create new chunks, they are called "unreleased". +// - Later these chunks are returned here, and become "released". +// - The manager is free to destroy or recycle the oldest released chunks +// (usually to reclaim memory), and will inform the user through a provided +// callback. +// - The user may access still-alive released chunks. +class ProfileBufferChunkManager { + public: + virtual ~ProfileBufferChunkManager() +#ifdef DEBUG + { + MOZ_ASSERT(!mUser, "Still registered when being destroyed"); + } +#else + = default; +#endif + + // Expected maximum size needed to store one stack sample. + // Most ChunkManager sub-classes will require chunk sizes, this can serve as + // a minimum recommendation to hold most backtraces. + constexpr static ProfileBufferChunk::Length scExpectedMaximumStackSize = + 128 * 1024; + + // Estimated maximum buffer size. + [[nodiscard]] virtual size_t MaxTotalSize() const = 0; + + // Create or recycle a chunk right now. May return null in case of allocation + // failure. + // Note that the chunk-destroyed callback may be invoked during this call; + // user should be careful with reentrancy issues. + [[nodiscard]] virtual UniquePtr GetChunk() = 0; + + // `aChunkReceiver` may be called with a new or recycled chunk, or nullptr. + // (See `FulfillChunkRequests()` regarding when the callback may happen.) + virtual void RequestChunk( + std::function)>&& aChunkReceiver) = 0; + + // This method may be invoked at any time on any thread (and not necessarily + // by the main user of this class), to do the work necessary to respond to a + // previous `RequestChunk()`. + // It is optional: If it is never called, or called too late, the user is + // responsible for directly calling `GetChunk()` when a chunk is really + // needed (or it should at least fail gracefully). + // The idea is to fulfill chunk request on a separate thread, and most + // importantly outside of profiler calls, to avoid doing expensive memory + // allocations during these calls. + virtual void FulfillChunkRequests() = 0; + + // One chunk is released by the user, the ProfileBufferChunkManager should + // keep it as long as possible (depending on local or global memory/time + // limits). Note that the chunk-destroyed callback may be invoked during this + // call; user should be careful with reentrancy issues. + virtual void ReleaseChunk(UniquePtr aChunk) = 0; + + // `aChunkDestroyedCallback` will be called whenever the contents of a + // previously-released chunk is about to be destroyed or recycled. + // Note that it may be called during other functions above, or at other times + // from the same or other threads; user should be careful with reentrancy + // issues. + virtual void SetChunkDestroyedCallback( + std::function&& + aChunkDestroyedCallback) = 0; + + // Give away all released chunks that have not yet been destroyed. + [[nodiscard]] virtual UniquePtr + GetExtantReleasedChunks() = 0; + + // Let a callback see all released chunks that have not yet been destroyed, if + // any. Return whatever the callback returns. + template + [[nodiscard]] auto PeekExtantReleasedChunks(Callback&& aCallback) { + const ProfileBufferChunk* chunks = PeekExtantReleasedChunksAndLock(); + auto unlock = + MakeScopeExit([&]() { UnlockAfterPeekExtantReleasedChunks(); }); + return std::forward(aCallback)(chunks); + } + + // Chunks that were still unreleased will never be released. + virtual void ForgetUnreleasedChunks() = 0; + + [[nodiscard]] virtual size_t SizeOfExcludingThis( + MallocSizeOf aMallocSizeOf) const = 0; + [[nodiscard]] virtual size_t SizeOfIncludingThis( + MallocSizeOf aMallocSizeOf) const = 0; + + protected: + // Derived classes to implement `PeekExtantReleasedChunks` through these: + virtual const ProfileBufferChunk* PeekExtantReleasedChunksAndLock() = 0; + virtual void UnlockAfterPeekExtantReleasedChunks() = 0; + +#ifdef DEBUG + public: + // DEBUG checks ensuring that this manager and its users avoid UAFs. + // Derived classes should assert that mUser is not null in their functions. + + void RegisteredWith(const void* aUser) { + MOZ_ASSERT(!mUser); + MOZ_ASSERT(aUser); + mUser = aUser; + } + + void DeregisteredFrom(const void* aUser) { + MOZ_ASSERT(mUser == aUser); + mUser = nullptr; + } + + protected: + const void* mUser = nullptr; +#endif // DEBUG +}; + +} // namespace mozilla + +#endif // ProfileBufferChunkManager_h -- cgit v1.2.3