| /* |
| * Copyright (C) 2016, 2018 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 "WebProcessPool.h" |
| #include <stdio.h> |
| #include <stdlib.h> |
| #include <string.h> |
| #include <unistd.h> |
| #include <wtf/Threading.h> |
| #include <wtf/UniStdExtras.h> |
| |
| namespace WebKit { |
| |
| static const size_t notSet = static_cast<size_t>(-1); |
| |
| static const Seconds s_minPollingInterval { 1_s }; |
| static const Seconds s_maxPollingInterval { 5_s }; |
| static const double s_minUsedMemoryPercentageForPolling = 50; |
| static const double s_maxUsedMemoryPercentageForPolling = 85; |
| static const int s_memoryPresurePercentageThreshold = 90; |
| static const int s_memoryPresurePercentageThresholdCritical = 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 Seconds 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_maxPollingInterval; |
| |
| if (usedPercentage >= s_maxUsedMemoryPercentageForPolling) |
| return s_minPollingInterval; |
| |
| return s_minPollingInterval + (s_maxPollingInterval - s_minPollingInterval) * |
| ((s_maxUsedMemoryPercentageForPolling - usedPercentage) / (s_maxUsedMemoryPercentageForPolling - s_minUsedMemoryPercentageForPolling)); |
| } |
| |
| MemoryPressureMonitor& MemoryPressureMonitor::singleton() |
| { |
| static NeverDestroyed<MemoryPressureMonitor> memoryMonitor; |
| return memoryMonitor; |
| } |
| |
| void MemoryPressureMonitor::start() |
| { |
| if (m_started) |
| return; |
| |
| m_started = true; |
| |
| Thread::create("MemoryPressureMonitor", [this] { |
| Seconds pollInterval = s_maxPollingInterval; |
| while (true) { |
| sleep(pollInterval); |
| |
| int usedPercentage = systemMemoryUsedAsPercentage(); |
| if (usedPercentage == -1) { |
| WTFLogAlways("Failed to get the memory usage"); |
| break; |
| } |
| |
| if (usedPercentage >= s_memoryPresurePercentageThreshold) { |
| bool isCritical = (usedPercentage >= s_memoryPresurePercentageThresholdCritical); |
| for (auto* processPool : WebProcessPool::allProcessPools()) |
| processPool->sendMemoryPressureEvent(isCritical); |
| } |
| pollInterval = pollIntervalForUsedMemoryPercentage(usedPercentage); |
| } |
| })->detach(); |
| } |
| |
| |
| } // namespace WebKit |
| |
| #endif // OS(LINUX) |