Bug 1822451 - Add about:memory entries for PHC r=glandium (dcda564f) · Commits · clairehurst / Tor Browser

memory/build/replace_malloc_bridge.h

+22 −2

Original line number	Diff line number	Diff line
		@@ -117,6 +117,16 @@ struct DMDFuncs;

		namespace phc {
		class AddrInfo;

		struct MemoryUsage {
		// The amount of memory used for PHC metadata, eg information about each
		// allocation including stacks.
		size_t mMetadataBytes = 0;

		// The amount of memory lost due to rounding allocation sizes up to the
		// nearest page. AKA internal fragmentation.
		size_t mFragmentationBytes = 0;
		};
		} // namespace phc

		// Callbacks to register debug file handles for Poison IO interpose.
		@@ -126,11 +136,10 @@ struct DebugFdRegistry {

		virtual void UnRegisterHandle(intptr_t aFd);
		};

		} // namespace mozilla

		struct ReplaceMallocBridge {
		ReplaceMallocBridge() : mVersion(4) {}
		ReplaceMallocBridge() : mVersion(5) {}

		// This method was added in version 1 of the bridge.
		virtual mozilla::dmd::DMDFuncs* GetDMDFuncs() { return nullptr; }
		@@ -182,6 +191,10 @@ struct ReplaceMallocBridge {
		// This method was added in version 4 of the bridge.
		virtual bool IsPHCEnabledOnCurrentThread() { return false; }

		// Return PHC memory usage information by filling in the supplied structure.
		// This method was added in version 5 of the bridge.
		virtual void PHCMemoryUsage(mozilla::phc::MemoryUsage& aMemoryUsage) {}

		# ifndef REPLACE_MALLOC_IMPL
		// Returns the replace-malloc bridge if its version is at least the
		// requested one.
		@@ -249,6 +262,13 @@ struct ReplaceMalloc {
		auto singleton = ReplaceMallocBridge::Get(/* minimumVersion */ 4);
		return singleton ? singleton->IsPHCEnabledOnCurrentThread() : false;
		}

		static void PHCMemoryUsage(mozilla::phc::MemoryUsage& aMemoryUsage) {
		auto singleton = ReplaceMallocBridge::Get(/* minimumVersion */ 5);
		if (singleton) {
		singleton->PHCMemoryUsage(aMemoryUsage);
		}
		}
		};
		# endif

memory/replace/phc/PHC.cpp

+35 −3

Original line number	Diff line number	Diff line
		@@ -656,6 +656,12 @@ class GMut {
		(kPageSize - 1));
		}

		// The internal fragmentation for this allocation.
		size_t FragmentationBytes() const {
		MOZ_ASSERT(kPageSize >= UsableSize());
		return mState == AllocPageState::InUse ? kPageSize - UsableSize() : 0;
		}

		// The allocation stack.
		// - NeverAllocated: Nothing.
		// - InUse \| Freed: Some.
		@@ -719,6 +725,15 @@ class GMut {
		return page.UsableSize();
		}

		// The total fragmentation in PHC
		size_t FragmentationBytes() const {
		size_t sum = 0;
		for (auto page : mAllocPages) {
		sum += page.FragmentationBytes();
		}
		return sum;
		}

		void SetPageInUse(GMutLock aLock, uintptr_t aIndex,
		const Maybe<arena_id_t>& aArenaId, uint8_t* aBaseAddr,
		const StackTrace& aAllocStack) {
		@@ -1389,6 +1404,11 @@ static size_t replace_malloc_usable_size(usable_ptr_t aPtr) {
		return gMut->PageUsableSize(lock, index);
		}

		static size_t metadata_size() {
		return sMallocTable.malloc_usable_size(gConst) +
		sMallocTable.malloc_usable_size(gMut);
		}

		void replace_jemalloc_stats(jemalloc_stats_t* aStats,
		jemalloc_bin_stats_t* aBinStats) {
		sMallocTable.jemalloc_stats_internal(aStats, aBinStats);
		@@ -1419,10 +1439,11 @@ void replace_jemalloc_stats(jemalloc_stats_t* aStats,
		// aStats.page_cache and aStats.bin_unused are left unchanged because PHC
		// doesn't have anything corresponding to those.

		// gConst and gMut are normal heap allocations, so they're measured by
		// The metadata is stored in normal heap allocations, so they're measured by
		// mozjemalloc as `allocated`. Move them into `bookkeeping`.
		size_t bookkeeping = sMallocTable.malloc_usable_size(gConst) +
		sMallocTable.malloc_usable_size(gMut);
		// They're also reported under explicit/heap-overhead/phc/fragmentation in
		// about:memory.
		size_t bookkeeping = metadata_size();
		aStats->allocated -= bookkeeping;
		aStats->bookkeeping += bookkeeping;
		}
		@@ -1554,6 +1575,17 @@ class PHCBridge : public ReplaceMallocBridge {
		LOG("IsPHCEnabledOnCurrentThread: %zu\n", size_t(enabled));
		return enabled;
		}

		virtual void PHCMemoryUsage(
		mozilla::phc::MemoryUsage& aMemoryUsage) override {
		aMemoryUsage.mMetadataBytes = metadata_size();
		if (gMut) {
		MutexAutoLock lock(GMut::sMutex);
		aMemoryUsage.mFragmentationBytes = gMut->FragmentationBytes();
		} else {
		aMemoryUsage.mFragmentationBytes = 0;
		}
		}
		};

		// WARNING: this function runs very early -- before all static initializers

xpcom/base/moz.build

+3 −0

Original line number	Diff line number	Diff line
		@@ -220,6 +220,9 @@ if CONFIG["OS_TARGET"] == "Linux":
		"AvailableMemoryWatcherUtils.h",
		]

		if CONFIG["MOZ_PHC"]:
		DEFINES["MOZ_PHC"] = True

		GeneratedFile("ErrorList.h", script="ErrorList.py", entry_point="error_list_h")
		GeneratedFile(
		"ErrorNamesInternal.h", script="ErrorList.py", entry_point="error_names_internal_h"

xpcom/base/nsMemoryReporterManager.cpp

+19 −0

Original line number	Diff line number	Diff line
		@@ -1335,6 +1335,25 @@ class JemallocHeapReporter final : public nsIMemoryReporter {
		MOZ_COLLECT_REPORT(
		"heap-chunksize", KIND_OTHER, UNITS_BYTES, stats.chunksize,
		"Size of chunks.");

		#ifdef MOZ_PHC
		mozilla::phc::MemoryUsage usage;
		ReplaceMalloc::PHCMemoryUsage(usage);

		MOZ_COLLECT_REPORT(
		"explicit/heap-overhead/phc/metadata", KIND_NONHEAP, UNITS_BYTES,
		usage.mMetadataBytes,
		"Memory used by PHC to store stacks and other metadata for each allocation");
		MOZ_COLLECT_REPORT(
		"explicit/heap-overhead/phc/fragmentation", KIND_NONHEAP, UNITS_BYTES,
		usage.mFragmentationBytes,
		"The amount of memory lost due to rounding up allocations to the next page "
		"size. "
		"This is also known as 'internal fragmentation'. "
		"Note that all allocators have some internal fragmentation, there may still "
		"be some internal fragmentation without PHC.");
		#endif

		// clang-format on

		return NS_OK;