/* * Copyright (C) 2016 Igalia S.L. * * Redistribution and use in source and binary forms, with or without * modification, are permitted provided that the following conditions * are met: * 1. Redistributions of source code must retain the above copyright * notice, this list of conditions and the following disclaimer. * 2. Redistributions in binary form must reproduce the above copyright * notice, this list of conditions and the following disclaimer in the * documentation and/or other materials provided with the distribution. * * THIS SOFTWARE IS PROVIDED BY APPLE INC. AND ITS CONTRIBUTORS ``AS IS'' * AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, * THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR * PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL APPLE INC. OR ITS CONTRIBUTORS * BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL, SPECIAL, EXEMPLARY, OR * CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT LIMITED TO, PROCUREMENT OF * SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, DATA, OR PROFITS; OR BUSINESS * INTERRUPTION) HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN * CONTRACT, STRICT LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) * ARISING IN ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF * THE POSSIBILITY OF SUCH DAMAGE. */ #include "config.h" #include "MemoryPressureMonitor.h" #if OS(LINUX) #include "Attachment.h" #include #include #include #include #include #include #include #include #include #include #include #include namespace WebKit { static const size_t notSet = static_cast(-1); static const double s_minPollingIntervalInSeconds = 1; static const double s_maxPollingIntervalInSeconds = 5; static const double s_minUsedMemoryPercentageForPolling = 50; static const double s_maxUsedMemoryPercentageForPolling = 90; static const int s_memoryPresurePercentageThreshold = 95; static size_t lowWatermarkPages() { FILE* file = fopen("/proc/zoneinfo", "r"); if (!file) return notSet; size_t low = 0; bool inZone = false; bool foundLow = false; char buffer[128]; while (char* line = fgets(buffer, 128, file)) { if (!strncmp(line, "Node", 4)) { inZone = true; foundLow = false; continue; } char* token = strtok(line, " "); if (!token) continue; if (!strcmp(token, "low")) { if (!inZone || foundLow) { low = notSet; break; } token = strtok(nullptr, " "); if (!token) { low = notSet; break; } low += atoll(token); foundLow = true; } } fclose(file); return low; } static inline size_t systemPageSize() { static size_t pageSize = 0; if (!pageSize) pageSize = sysconf(_SC_PAGE_SIZE); return pageSize; } // If MemAvailable was not present in /proc/meminfo, because it's an old kernel version, // we can do the same calculation with the information we have from meminfo and the low watermaks. // See https://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=34e431b0ae398fc54ea69ff85ec700722c9da773 static size_t calculateMemoryAvailable(size_t memoryFree, size_t activeFile, size_t inactiveFile, size_t slabReclaimable) { if (memoryFree == notSet || activeFile == notSet || inactiveFile == notSet || slabReclaimable == notSet) return notSet; size_t lowWatermark = lowWatermarkPages(); if (lowWatermark == notSet) return notSet; lowWatermark *= systemPageSize() / KB; // Estimate the amount of memory available for userspace allocations, without causing swapping. // Free memory cannot be taken below the low watermark, before the system starts swapping. lowWatermark *= systemPageSize() / KB; size_t memoryAvailable = memoryFree - lowWatermark; // Not all the page cache can be freed, otherwise the system will start swapping. Assume at least // half of the page cache, or the low watermark worth of cache, needs to stay. size_t pageCache = activeFile + inactiveFile; pageCache -= std::min(pageCache / 2, lowWatermark); memoryAvailable += pageCache; // Part of the reclaimable slab consists of items that are in use, and cannot be freed. // Cap this estimate at the low watermark. memoryAvailable += slabReclaimable - std::min(slabReclaimable / 2, lowWatermark); return memoryAvailable; } static int systemMemoryUsedAsPercentage() { FILE* file = fopen("/proc/meminfo", "r"); if (!file) return -1; size_t memoryAvailable, memoryTotal, memoryFree, activeFile, inactiveFile, slabReclaimable; memoryAvailable = memoryTotal = memoryFree = activeFile = inactiveFile = slabReclaimable = notSet; char buffer[128]; while (char* line = fgets(buffer, 128, file)) { char* token = strtok(line, " "); if (!token) break; if (!strcmp(token, "MemAvailable:")) { if ((token = strtok(nullptr, " "))) { memoryAvailable = atoll(token); if (memoryTotal != notSet) break; } } else if (!strcmp(token, "MemTotal:")) { if ((token = strtok(nullptr, " "))) memoryTotal = atoll(token); else break; } else if (!strcmp(token, "MemFree:")) { if ((token = strtok(nullptr, " "))) memoryFree = atoll(token); else break; } else if (!strcmp(token, "Active(file):")) { if ((token = strtok(nullptr, " "))) activeFile = atoll(token); else break; } else if (!strcmp(token, "Inactive(file):")) { if ((token = strtok(nullptr, " "))) inactiveFile = atoll(token); else break; } else if (!strcmp(token, "SReclaimable:")) { if ((token = strtok(nullptr, " "))) slabReclaimable = atoll(token); else break; } if (memoryTotal != notSet && memoryFree != notSet && activeFile != notSet && inactiveFile != notSet && slabReclaimable != notSet) break; } fclose(file); if (!memoryTotal || memoryTotal == notSet) return -1; if (memoryAvailable == notSet) { memoryAvailable = calculateMemoryAvailable(memoryFree, activeFile, inactiveFile, slabReclaimable); if (memoryAvailable == notSet) return -1; } if (memoryAvailable > memoryTotal) return -1; return ((memoryTotal - memoryAvailable) * 100) / memoryTotal; } static inline double pollIntervalForUsedMemoryPercentage(int usedPercentage) { // Use a different poll interval depending on the currently memory used, // to avoid polling too often when the system is under low memory usage. if (usedPercentage < s_minUsedMemoryPercentageForPolling) return s_maxPollingIntervalInSeconds; if (usedPercentage >= s_maxUsedMemoryPercentageForPolling) return s_minPollingIntervalInSeconds; return s_minPollingIntervalInSeconds + (s_maxPollingIntervalInSeconds - s_minPollingIntervalInSeconds) * ((usedPercentage - s_minUsedMemoryPercentageForPolling) / (s_maxUsedMemoryPercentageForPolling - s_minUsedMemoryPercentageForPolling)); } static bool isSystemdMemoryPressureMonitorAvailable() { int fd = open("/sys/fs/cgroup/memory/memory.pressure_level", O_CLOEXEC | O_RDONLY); if (fd == -1) return false; close(fd); fd = open("/sys/fs/cgroup/memory/cgroup.event_control", O_CLOEXEC | O_WRONLY); if (fd == -1) return false; close(fd); return true; } bool MemoryPressureMonitor::isEnabled() { static std::once_flag onceFlag; static bool enabled; std::call_once(onceFlag, [] { enabled = !isSystemdMemoryPressureMonitorAvailable(); }); return enabled; } MemoryPressureMonitor& MemoryPressureMonitor::singleton() { ASSERT(isEnabled()); static NeverDestroyed memoryMonitor; return memoryMonitor; } MemoryPressureMonitor::MemoryPressureMonitor() : m_eventFD(eventfd(0, EFD_CLOEXEC)) { if (m_eventFD == -1) return; ThreadIdentifier threadIdentifier = createThread("MemoryPressureMonitor", [this] { double pollInterval = s_maxPollingIntervalInSeconds; while (true) { sleep(pollInterval); int usedPercentage = systemMemoryUsedAsPercentage(); if (usedPercentage == -1) { WTFLogAlways("Failed to get the memory usage"); break; } if (usedPercentage >= s_memoryPresurePercentageThreshold) { uint64_t fdEvent = 1; ssize_t bytesWritten = write(m_eventFD, &fdEvent, sizeof(uint64_t)); if (bytesWritten != sizeof(uint64_t)) { WTFLogAlways("Error writing to MemoryPressureMonitor eventFD: %s", strerror(errno)); break; } } pollInterval = pollIntervalForUsedMemoryPercentage(usedPercentage); } close(m_eventFD); }); detachThread(threadIdentifier); } IPC::Attachment MemoryPressureMonitor::createHandle() const { int duplicatedHandle = dupCloseOnExec(m_eventFD); if (duplicatedHandle == -1) return { }; return IPC::Attachment(duplicatedHandle); } } // namespace WebKit #endif // OS(LINUX)