Function getMachineRAMInfo

flow/Platform.actor.cpp:443–569

#endif

void getMachineRAMInfo(MachineRAMInfo& memInfo) {
#if defined(__linux__)
	std::ifstream zoneInfoFileStream("/proc/zoneinfo", std::ifstream::in);
	int64_t lowWatermark = 0;
	if (!zoneInfoFileStream.good()) {
		TraceEvent(SevWarnAlways, "GetMachineZoneInfo").GetLastError();
	} else {
		std::stringstream zoneInfoStream;
		zoneInfoStream << zoneInfoFileStream.rdbuf();
		lowWatermark = getLowWatermark(zoneInfoStream) * 4; // Convert from 4K pages to KB
	}

	std::ifstream fileStream("/proc/meminfo", std::ifstream::in);
	if (!fileStream.good()) {
		TraceEvent(SevError, "GetMachineMemInfo").GetLastError();
		throw platform_error();
	}

	std::map<StringRef, int64_t> request = {
		{ LiteralStringRef("MemTotal:"), 0 },       { LiteralStringRef("MemFree:"), 0 },
		{ LiteralStringRef("MemAvailable:"), -1 },  { LiteralStringRef("Active(file):"), 0 },
		{ LiteralStringRef("Inactive(file):"), 0 }, { LiteralStringRef("SwapTotal:"), 0 },
		{ LiteralStringRef("SwapFree:"), 0 },       { LiteralStringRef("SReclaimable:"), 0 },
	};

	std::stringstream memInfoStream;
	memInfoStream << fileStream.rdbuf();
	getMemoryInfo(request, memInfoStream);

	int64_t memFree = request[LiteralStringRef("MemFree:")];
	int64_t pageCache = request[LiteralStringRef("Active(file):")] + request[LiteralStringRef("Inactive(file):")];
	int64_t slabReclaimable = request[LiteralStringRef("SReclaimable:")];
	int64_t usedSwap = request[LiteralStringRef("SwapTotal:")] - request[LiteralStringRef("SwapFree:")];

	memInfo.total = 1024 * request[LiteralStringRef("MemTotal:")];
	if (request[LiteralStringRef("MemAvailable:")] != -1) {
		memInfo.available = 1024 * (request[LiteralStringRef("MemAvailable:")] - usedSwap);
	} else {
		memInfo.available =
		    1024 * (std::max<int64_t>(0,
		                              (memFree - lowWatermark) + std::max(pageCache - lowWatermark, pageCache / 2) +
		                                  std::max(slabReclaimable - lowWatermark, slabReclaimable / 2)) -
		            usedSwap);
	}

	memInfo.committed = memInfo.total - memInfo.available;
#elif defined(__FreeBSD__)
	int status;

	u_int page_size;
	u_int free_count;
	u_int active_count;
	u_int inactive_count;
	u_int wire_count;

	size_t uint_size;

	uint_size = sizeof(page_size);