/**
* Kill the task and clean up ProcessTreeInfo
*
* @param tid task attempt ID of the task to be killed.
* @param msg diagonostic message
* @param wasFailure if true, fail the task
*/
private void killTask(TaskAttemptID tid, String msg, boolean wasFailure) {
// Kill the task and mark it as killed.
taskTracker.cleanUpOverMemoryTask(tid, wasFailure, msg);
// Now destroy the ProcessTree, remove it from monitoring map.
ProcessTreeInfo ptInfo = processTreeInfoMap.get(tid);
ProcfsBasedProcessTree pTree = ptInfo.getProcessTree();
try {
LinuxSystemCall.killProcessGroup(Integer.parseInt(ptInfo.getPID()));
} catch (java.io.IOException e) {
LOG.error("Could not kill process group " + ptInfo.getPID(), e);
}
processTreeInfoMap.remove(tid);
LOG.info("Removed ProcessTree with root " + ptInfo.getPID());
}
private void killTasksWithLeastProgress(long memoryStillInUsage) {
List<TaskAttemptID> tasksToKill = new ArrayList<TaskAttemptID>();
List<TaskAttemptID> tasksToExclude = new ArrayList<TaskAttemptID>();
// Find tasks to kill so as to get memory usage under limits.
while (memoryStillInUsage > maxMemoryAllowedForAllTasks) {
// Exclude tasks that are already marked for
// killing.
TaskInProgress task = taskTracker.findTaskToKill(tasksToExclude);
if (task == null) {
break; // couldn't find any more tasks to kill.
}
TaskAttemptID tid = task.getTask().getTaskID();
if (processTreeInfoMap.containsKey(tid)) {
ProcessTreeInfo ptInfo = processTreeInfoMap.get(tid);
ProcfsBasedProcessTree pTree = ptInfo.getProcessTree();
memoryStillInUsage -= pTree.getCumulativeVmem();
tasksToKill.add(tid);
}
// Exclude this task from next search because it is already
// considered.
tasksToExclude.add(tid);
}
// Now kill the tasks.
if (!tasksToKill.isEmpty()) {
for (TaskAttemptID tid : tasksToKill) {
String msg =
"Killing one of the least progress tasks - "
+ tid
+ ", as the cumulative memory usage of all the tasks on "
+ "the TaskTracker exceeds virtual memory limit "
+ maxMemoryAllowedForAllTasks
+ ".";
LOG.warn(msg);
killTask(tid, msg, false);
}
} else {
LOG.info(
"The total memory usage is overflowing TTs limits. "
+ "But found no alive task to kill for freeing memory.");
}
}
/**
* Return the cumulative rss memory used by a task
*
* @param tid the task attempt ID of the task
* @return rss memory usage in bytes. 0 if the process tree is not available
*/
private long getTaskCumulativeRssmem(TaskAttemptID tid) {
ProcessTreeInfo ptInfo = processTreeInfoMap.get(tid);
ProcfsBasedProcessTree pTree = ptInfo.getProcessTree();
return pTree == null ? 0 : pTree.getCumulativeVmem();
}
@Override
public void run() {
LOG.info("Starting thread: " + this.getClass());
while (running) {
try {
// Print the processTrees for debugging.
if (LOG.isDebugEnabled()) {
StringBuffer tmp = new StringBuffer("[ ");
for (ProcessTreeInfo p : processTreeInfoMap.values()) {
tmp.append(p.getPID());
tmp.append(" ");
}
LOG.debug("Current ProcessTree list : " + tmp.substring(0, tmp.length()) + "]");
}
// Add new Tasks
synchronized (tasksToBeAdded) {
processTreeInfoMap.putAll(tasksToBeAdded);
tasksToBeAdded.clear();
}
// Remove finished Tasks
synchronized (tasksToBeRemoved) {
for (TaskAttemptID tid : tasksToBeRemoved) {
processTreeInfoMap.remove(tid);
}
tasksToBeRemoved.clear();
}
long memoryStillInUsage = 0;
long rssMemoryStillInUsage = 0;
// Now, check memory usage and kill any overflowing tasks
for (Iterator<Map.Entry<TaskAttemptID, ProcessTreeInfo>> it =
processTreeInfoMap.entrySet().iterator();
it.hasNext(); ) {
Map.Entry<TaskAttemptID, ProcessTreeInfo> entry = it.next();
TaskAttemptID tid = entry.getKey();
ProcessTreeInfo ptInfo = entry.getValue();
try {
String pId = ptInfo.getPID();
// Initialize any uninitialized processTrees
if (pId == null) {
// get pid from taskAttemptId
pId = taskTracker.getPid(ptInfo.getTID());
if (pId != null) {
// PID will be null, either if the pid file is yet to be created
// or if the tip is finished and we removed pidFile, but the TIP
// itself is still retained in runningTasks till successful
// transmission to JT
// create process tree object
long sleeptimeBeforeSigkill =
taskTracker
.getJobConf()
.getLong(
"mapred.tasktracker.tasks.sleeptime-before-sigkill",
ProcessTree.DEFAULT_SLEEPTIME_BEFORE_SIGKILL);
ProcfsBasedProcessTree pt =
new ProcfsBasedProcessTree(
pId, ProcessTree.isSetsidAvailable, sleeptimeBeforeSigkill);
LOG.debug("Tracking ProcessTree " + pId + " for the first time");
ptInfo.setPid(pId);
ptInfo.setProcessTree(pt);
}
}
// End of initializing any uninitialized processTrees
if (pId == null) {
continue; // processTree cannot be tracked
}
LOG.debug("Constructing ProcessTree for : PID = " + pId + " TID = " + tid);
ProcfsBasedProcessTree pTree = ptInfo.getProcessTree();
pTree = pTree.getProcessTree(); // get the updated process-tree
ptInfo.setProcessTree(pTree); // update ptInfo with process-tree of
// updated state
long currentMemUsage = pTree.getCumulativeVmem();
long currentRssMemUsage = pTree.getCumulativeRssmem();
// as processes begin with an age 1, we want to see if there
// are processes more than 1 iteration old.
long curMemUsageOfAgedProcesses = pTree.getCumulativeVmem(1);
long limit = ptInfo.getMemLimit();
String user = taskTracker.getUserName(ptInfo.tid);
if (user == null) {
// If user is null the task is deleted from the TT memory
continue;
}
// Log RSS and virtual memory usage of all tasks
LOG.debug(
(String.format(
"Memory usage of ProcessTree %s : "
+ "[USER,TID,RSS,VMEM,VLimit,TotalRSSLimit]"
+ "=[%s,%s,%s,%s,%s,%s]",
pId,
user,
ptInfo.tid,
currentRssMemUsage,
currentMemUsage,
limit,
maxRssMemoryAllowedForAllTasks)));
if (doCheckVirtualMemory()
&& isProcessTreeOverLimit(
tid.toString(), currentMemUsage, curMemUsageOfAgedProcesses, limit)) {
// Task (the root process) is still alive and overflowing memory.
// Dump the process-tree and then clean it up.
String msg =
"TaskTree [pid="
+ pId
+ ",tipID="
+ tid
+ "] is running beyond memory-limits. Current usage : "
+ currentMemUsage
+ "bytes. Limit : "
+ limit
+ "bytes. Killing task. \nDump of the process-tree for "
+ tid
+ " : \n"
+ pTree.getProcessTreeDump();
LOG.warn(msg);
taskTracker.cleanUpOverMemoryTask(tid, true, msg);
LinuxSystemCall.killProcessGroup(Integer.parseInt(pId));
it.remove();
LOG.info("Removed ProcessTree with root " + pId);
} else {
// Accounting the total memory in usage for all tasks that are still
// alive and within limits.
memoryStillInUsage += currentMemUsage;
rssMemoryStillInUsage += currentRssMemUsage;
}
} catch (Exception e) {
// Log the exception and proceed to the next task.
LOG.warn(
"Uncaught exception in TaskMemoryManager " + "while managing memory of " + tid, e);
}
}
long availableRssMemory = resourceCalculator.getAvailablePhysicalMemorySize();
LOG.info(
"vMemory:"
+ memoryStillInUsage
+ " rssMemory:"
+ rssMemoryStillInUsage
+ " rssMemoryLimit:"
+ maxRssMemoryAllowedForAllTasks
+ " rssMemoryAvailable:"
+ availableRssMemory
+ " rssMemoryReserved:"
+ reservedRssMemory
+ " totalTasks:"
+ processTreeInfoMap.size());
if (doCheckVirtualMemory() && memoryStillInUsage > maxMemoryAllowedForAllTasks) {
LOG.warn(
"The total memory in usage "
+ memoryStillInUsage
+ " is overflowing TTs limits "
+ maxMemoryAllowedForAllTasks
+ ". Trying to kill a few tasks with the least progress.");
killTasksWithLeastProgress(memoryStillInUsage);
}
updateMaxRssMemory();
if (doCheckPhysicalMemory()
&& (rssMemoryStillInUsage > maxRssMemoryAllowedForAllTasks
|| availableRssMemory < reservedRssMemory)) {
LOG.warn(
"The total physical memory in usage "
+ rssMemoryStillInUsage
+ " is overflowing TTs limits "
+ maxRssMemoryAllowedForAllTasks
+ ". Trying to kill a few tasks with the highest memory.");
failTasksWithMaxRssMemory(rssMemoryStillInUsage, availableRssMemory);
}
// Sleep for some time before beginning next cycle
LOG.debug(this.getClass() + " : Sleeping for " + monitoringInterval + " ms");
Thread.sleep(monitoringInterval);
} catch (InterruptedException iex) {
if (running) {
LOG.error("Class " + this.getClass() + " was interrupted", iex);
}
} catch (Throwable t) {
LOG.error("Class " + this.getClass() + " encountered error", t);
}
}
}
