Srinivas Paladugu | c826175 | 2019-01-09 10:54:52 -0800 | [diff] [blame] | 1 | /* |
| 2 | * Copyright (C) 2019 The Android Open Source Project |
| 3 | * |
| 4 | * Licensed under the Apache License, Version 2.0 (the "License"); |
| 5 | * you may not use this file except in compliance with the License. |
| 6 | * You may obtain a copy of the License at |
| 7 | * |
| 8 | * http://www.apache.org/licenses/LICENSE-2.0 |
| 9 | * |
| 10 | * Unless required by applicable law or agreed to in writing, software |
| 11 | * distributed under the License is distributed on an "AS IS" BASIS, |
| 12 | * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. |
| 13 | * See the License for the specific language governing permissions and |
| 14 | * limitations under the License. |
| 15 | */ |
| 16 | |
| 17 | package com.android.server; |
| 18 | |
| 19 | import android.app.job.JobInfo; |
| 20 | import android.app.job.JobParameters; |
| 21 | import android.app.job.JobScheduler; |
| 22 | import android.app.job.JobService; |
| 23 | import android.content.ComponentName; |
| 24 | import android.content.Context; |
| 25 | import android.os.FileUtils; |
| 26 | import android.os.SystemProperties; |
| 27 | import android.util.Slog; |
| 28 | |
| 29 | import java.io.File; |
| 30 | import java.io.IOException; |
| 31 | import java.util.concurrent.TimeUnit; |
| 32 | |
| 33 | /** |
| 34 | * Schedules jobs for triggering zram writeback. |
| 35 | */ |
| 36 | public final class ZramWriteback extends JobService { |
| 37 | private static final String TAG = "ZramWriteback"; |
| 38 | private static final boolean DEBUG = false; |
| 39 | |
| 40 | private static final ComponentName sZramWriteback = |
| 41 | new ComponentName("android", ZramWriteback.class.getName()); |
| 42 | |
| 43 | private static final int MARK_IDLE_JOB_ID = 811; |
| 44 | private static final int WRITEBACK_IDLE_JOB_ID = 812; |
| 45 | |
| 46 | private static final int MAX_ZRAM_DEVICES = 256; |
| 47 | private static int sZramDeviceId = 0; |
| 48 | |
| 49 | private static final String IDLE_SYS = "/sys/block/zram%d/idle"; |
| 50 | private static final String IDLE_SYS_ALL_PAGES = "all"; |
| 51 | |
| 52 | private static final String WB_SYS = "/sys/block/zram%d/writeback"; |
| 53 | private static final String WB_SYS_IDLE_PAGES = "idle"; |
| 54 | |
| 55 | private static final String WB_STATS_SYS = "/sys/block/zram%d/bd_stat"; |
| 56 | private static final int WB_STATS_MAX_FILE_SIZE = 128; |
| 57 | |
| 58 | private static final String BDEV_SYS = "/sys/block/zram%d/backing_dev"; |
| 59 | |
| 60 | private static final String MARK_IDLE_DELAY_PROP = "ro.zram.mark_idle_delay_mins"; |
| 61 | private static final String FIRST_WB_DELAY_PROP = "ro.zram.first_wb_delay_mins"; |
| 62 | private static final String PERIODIC_WB_DELAY_PROP = "ro.zram.periodic_wb_delay_hours"; |
| 63 | |
| 64 | private void markPagesAsIdle() { |
| 65 | String idlePath = String.format(IDLE_SYS, sZramDeviceId); |
| 66 | try { |
| 67 | FileUtils.stringToFile(new File(idlePath), IDLE_SYS_ALL_PAGES); |
| 68 | } catch (IOException e) { |
| 69 | Slog.e(TAG, "Failed to write to " + idlePath); |
| 70 | } |
| 71 | } |
| 72 | |
| 73 | private void flushIdlePages() { |
| 74 | if (DEBUG) Slog.d(TAG, "Start writing back idle pages to disk"); |
| 75 | String wbPath = String.format(WB_SYS, sZramDeviceId); |
| 76 | try { |
| 77 | FileUtils.stringToFile(new File(wbPath), WB_SYS_IDLE_PAGES); |
| 78 | } catch (IOException e) { |
| 79 | Slog.e(TAG, "Failed to write to " + wbPath); |
| 80 | } |
| 81 | if (DEBUG) Slog.d(TAG, "Finished writeback back idle pages"); |
| 82 | } |
| 83 | |
| 84 | private int getWrittenPageCount() { |
| 85 | String wbStatsPath = String.format(WB_STATS_SYS, sZramDeviceId); |
| 86 | try { |
| 87 | String wbStats = FileUtils |
| 88 | .readTextFile(new File(wbStatsPath), WB_STATS_MAX_FILE_SIZE, ""); |
| 89 | return Integer.parseInt(wbStats.trim().split("\\s+")[2], 10); |
| 90 | } catch (IOException e) { |
| 91 | Slog.e(TAG, "Failed to read writeback stats from " + wbStatsPath); |
| 92 | } |
| 93 | |
| 94 | return -1; |
| 95 | } |
| 96 | |
| 97 | private void markAndFlushPages() { |
| 98 | int pageCount = getWrittenPageCount(); |
| 99 | |
| 100 | flushIdlePages(); |
| 101 | markPagesAsIdle(); |
| 102 | |
| 103 | if (pageCount != -1) { |
| 104 | Slog.i(TAG, "Total pages written to disk is " + (getWrittenPageCount() - pageCount)); |
| 105 | } |
| 106 | } |
| 107 | |
| 108 | private static boolean isWritebackEnabled() { |
| 109 | try { |
| 110 | String backingDev = FileUtils |
| 111 | .readTextFile(new File(String.format(BDEV_SYS, sZramDeviceId)), 128, ""); |
| 112 | if (!"none".equals(backingDev.trim())) { |
| 113 | return true; |
| 114 | } else { |
| 115 | Slog.w(TAG, "Writeback device is not set"); |
| 116 | } |
| 117 | } catch (IOException e) { |
| 118 | Slog.w(TAG, "Writeback is not enabled on zram"); |
| 119 | } |
| 120 | return false; |
| 121 | } |
| 122 | |
| 123 | private static void schedNextWriteback(Context context) { |
| 124 | int nextWbDelay = SystemProperties.getInt(PERIODIC_WB_DELAY_PROP, 24); |
| 125 | JobScheduler js = (JobScheduler) context.getSystemService(Context.JOB_SCHEDULER_SERVICE); |
| 126 | |
| 127 | js.schedule(new JobInfo.Builder(WRITEBACK_IDLE_JOB_ID, sZramWriteback) |
| 128 | .setMinimumLatency(TimeUnit.HOURS.toMillis(nextWbDelay)) |
| 129 | .setRequiresDeviceIdle(true) |
| 130 | .build()); |
| 131 | } |
| 132 | |
| 133 | @Override |
| 134 | public boolean onStartJob(JobParameters params) { |
| 135 | |
| 136 | if (!isWritebackEnabled()) { |
| 137 | jobFinished(params, false); |
| 138 | return false; |
| 139 | } |
| 140 | |
| 141 | if (params.getJobId() == MARK_IDLE_JOB_ID) { |
| 142 | markPagesAsIdle(); |
| 143 | jobFinished(params, false); |
| 144 | return false; |
| 145 | } else { |
| 146 | new Thread("ZramWriteback_WritebackIdlePages") { |
| 147 | @Override |
| 148 | public void run() { |
| 149 | markAndFlushPages(); |
| 150 | schedNextWriteback(ZramWriteback.this); |
| 151 | jobFinished(params, false); |
| 152 | } |
| 153 | }.start(); |
| 154 | } |
| 155 | return true; |
| 156 | } |
| 157 | |
| 158 | @Override |
| 159 | public boolean onStopJob(JobParameters params) { |
| 160 | // The thread that triggers the writeback is non-interruptible |
| 161 | return false; |
| 162 | } |
| 163 | |
| 164 | /** |
| 165 | * Schedule the zram writeback job to trigger a writeback when idle |
| 166 | */ |
| 167 | public static void scheduleZramWriteback(Context context) { |
| 168 | int markIdleDelay = SystemProperties.getInt(MARK_IDLE_DELAY_PROP, 20); |
| 169 | int firstWbDelay = SystemProperties.getInt(FIRST_WB_DELAY_PROP, 180); |
| 170 | |
| 171 | JobScheduler js = (JobScheduler) context.getSystemService(Context.JOB_SCHEDULER_SERVICE); |
| 172 | |
| 173 | // Schedule a one time job to mark pages as idle. These pages will be written |
| 174 | // back at later point if they remain untouched. |
| 175 | js.schedule(new JobInfo.Builder(MARK_IDLE_JOB_ID, sZramWriteback) |
| 176 | .setMinimumLatency(TimeUnit.MINUTES.toMillis(markIdleDelay)) |
| 177 | .build()); |
| 178 | |
| 179 | // Schedule a one time job to flush idle pages to disk. |
| 180 | // After the initial writeback, subsequent writebacks are done at interval set |
| 181 | // by ro.zram.periodic_wb_delay_hours. |
| 182 | js.schedule(new JobInfo.Builder(WRITEBACK_IDLE_JOB_ID, sZramWriteback) |
| 183 | .setMinimumLatency(TimeUnit.MINUTES.toMillis(firstWbDelay)) |
| 184 | .setRequiresDeviceIdle(true) |
| 185 | .build()); |
| 186 | } |
| 187 | } |