/* * Copyright (C) 2018 The Android Open Source Project * * Licensed under the Apache License, Version 2.0 (the "License"); * you may not use this file except in compliance with the License. * You may obtain a copy of the License at * * http://www.apache.org/licenses/LICENSE-2.0 * * Unless required by applicable law or agreed to in writing, software * distributed under the License is distributed on an "AS IS" BASIS, * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. * See the License for the specific language governing permissions and * limitations under the License. */ package com.android.server.am; import static com.android.server.am.ActivityManagerDebugConfig.DEBUG_METRICS; import static com.android.server.am.ActivityManagerDebugConfig.TAG_AM; import static com.android.server.am.ActivityManagerDebugConfig.TAG_WITH_CLASS_NAME; import android.annotation.Nullable; import android.os.FileUtils; import android.util.Slog; import com.android.internal.annotations.VisibleForTesting; import java.io.File; import java.io.IOException; import java.util.Locale; import java.util.regex.Matcher; import java.util.regex.Pattern; /** * Static utility methods related to {@link MemoryStat}. */ final class MemoryStatUtil { private static final String TAG = TAG_WITH_CLASS_NAME ? "MemoryStatUtil" : TAG_AM; /** Path to check if device has memcg */ private static final String MEMCG_TEST_PATH = "/dev/memcg/apps/memory.stat"; /** Path to memory stat file for logging app start memory state */ private static final String MEMORY_STAT_FILE_FMT = "/dev/memcg/apps/uid_%d/pid_%d/memory.stat"; /** Path to procfs stat file for logging app start memory state */ private static final String PROC_STAT_FILE_FMT = "/proc/%d/stat"; private static final Pattern PGFAULT = Pattern.compile("total_pgfault (\\d+)"); private static final Pattern PGMAJFAULT = Pattern.compile("total_pgmajfault (\\d+)"); private static final Pattern RSS_IN_BYTES = Pattern.compile("total_rss (\\d+)"); private static final Pattern CACHE_IN_BYTES = Pattern.compile("total_cache (\\d+)"); private static final Pattern SWAP_IN_BYTES = Pattern.compile("total_swap (\\d+)"); private static final int PGFAULT_INDEX = 9; private static final int PGMAJFAULT_INDEX = 11; private static final int RSS_IN_BYTES_INDEX = 23; /** True if device has memcg */ private static volatile Boolean sDeviceHasMemCg; private MemoryStatUtil() {} /** * Reads memory stat for a process. * * Reads from memcg if available on device, else fallback to procfs. * Returns null if no stats can be read. */ @Nullable static MemoryStat readMemoryStatFromFilesystem(int uid, int pid) { return hasMemcg() ? readMemoryStatFromMemcg(uid, pid) : readMemoryStatFromProcfs(pid); } /** * Reads memory.stat of a process from memcg. * * Returns null if file is not found in memcg or if file has unrecognized contents. */ @Nullable static MemoryStat readMemoryStatFromMemcg(int uid, int pid) { final String path = String.format(Locale.US, MEMORY_STAT_FILE_FMT, uid, pid); return parseMemoryStatFromMemcg(readFileContents(path)); } /** * Reads memory stat of a process from procfs. * * Returns null if file is not found in procfs or if file has unrecognized contents. */ @Nullable static MemoryStat readMemoryStatFromProcfs(int pid) { final String path = String.format(Locale.US, PROC_STAT_FILE_FMT, pid); return parseMemoryStatFromProcfs(readFileContents(path)); } private static String readFileContents(String path) { final File file = new File(path); if (!file.exists()) { if (DEBUG_METRICS) Slog.i(TAG, path + " not found"); return null; } try { return FileUtils.readTextFile(file, 0 /* max */, null /* ellipsis */); } catch (IOException e) { Slog.e(TAG, "Failed to read file:", e); return null; } } /** * Parses relevant statistics out from the contents of a memory.stat file in memcg. */ @VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE) @Nullable static MemoryStat parseMemoryStatFromMemcg(String memoryStatContents) { if (memoryStatContents == null || memoryStatContents.isEmpty()) { return null; } final MemoryStat memoryStat = new MemoryStat(); Matcher m; m = PGFAULT.matcher(memoryStatContents); memoryStat.pgfault = m.find() ? Long.valueOf(m.group(1)) : 0; m = PGMAJFAULT.matcher(memoryStatContents); memoryStat.pgmajfault = m.find() ? Long.valueOf(m.group(1)) : 0; m = RSS_IN_BYTES.matcher(memoryStatContents); memoryStat.rssInBytes = m.find() ? Long.valueOf(m.group(1)) : 0; m = CACHE_IN_BYTES.matcher(memoryStatContents); memoryStat.cacheInBytes = m.find() ? Long.valueOf(m.group(1)) : 0; m = SWAP_IN_BYTES.matcher(memoryStatContents); memoryStat.swapInBytes = m.find() ? Long.valueOf(m.group(1)) : 0; return memoryStat; } /** * Parses relevant statistics out from the contents of a /proc/pid/stat file in procfs. */ @VisibleForTesting(visibility = VisibleForTesting.Visibility.PRIVATE) @Nullable static MemoryStat parseMemoryStatFromProcfs(String procStatContents) { if (procStatContents == null || procStatContents.isEmpty()) { return null; } final String[] splits = procStatContents.split(" "); if (splits.length < 24) { return null; } final MemoryStat memoryStat = new MemoryStat(); memoryStat.pgfault = Long.valueOf(splits[PGFAULT_INDEX]); memoryStat.pgmajfault = Long.valueOf(splits[PGMAJFAULT_INDEX]); memoryStat.rssInBytes = Long.valueOf(splits[RSS_IN_BYTES_INDEX]); return memoryStat; } /** * Checks if memcg is available on device. * * Touches the filesystem to do the check. */ static boolean hasMemcg() { if (sDeviceHasMemCg == null) { sDeviceHasMemCg = (new File(MEMCG_TEST_PATH)).exists(); } return sDeviceHasMemCg; } static final class MemoryStat { /** Number of page faults */ long pgfault; /** Number of major page faults */ long pgmajfault; /** Number of bytes of anonymous and swap cache memory */ long rssInBytes; /** Number of bytes of page cache memory */ long cacheInBytes; /** Number of bytes of swap usage */ long swapInBytes; } }