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Posted to mapreduce-commits@hadoop.apache.org by cd...@apache.org on 2009/10/19 02:19:23 UTC
svn commit: r826566 - in /hadoop/mapreduce/branches/branch-0.21: CHANGES.txt
src/contrib/fairscheduler/src/java/org/apache/hadoop/mapred/FairSchedulerServlet.java
Author: cdouglas
Date: Mon Oct 19 00:19:23 2009
New Revision: 826566
URL: http://svn.apache.org/viewvc?rev=826566&view=rev
Log:
MAPREDUCE-1070. Prevent a deadlock in the fair scheduler servlet.
Contributed by Todd Lipcon
Modified:
hadoop/mapreduce/branches/branch-0.21/CHANGES.txt
hadoop/mapreduce/branches/branch-0.21/src/contrib/fairscheduler/src/java/org/apache/hadoop/mapred/FairSchedulerServlet.java
Modified: hadoop/mapreduce/branches/branch-0.21/CHANGES.txt
URL: http://svn.apache.org/viewvc/hadoop/mapreduce/branches/branch-0.21/CHANGES.txt?rev=826566&r1=826565&r2=826566&view=diff
==============================================================================
--- hadoop/mapreduce/branches/branch-0.21/CHANGES.txt (original)
+++ hadoop/mapreduce/branches/branch-0.21/CHANGES.txt Mon Oct 19 00:19:23 2009
@@ -767,3 +767,6 @@
MAPREDUCE-1041. Make TaskInProgress::taskStatuses map package-private.
(Jothi Padmanabhan via cdouglas)
+
+ MAPREDUCE-1070. Prevent a deadlock in the fair scheduler servlet.
+ (Todd Lipcon via cdouglas)
Modified: hadoop/mapreduce/branches/branch-0.21/src/contrib/fairscheduler/src/java/org/apache/hadoop/mapred/FairSchedulerServlet.java
URL: http://svn.apache.org/viewvc/hadoop/mapreduce/branches/branch-0.21/src/contrib/fairscheduler/src/java/org/apache/hadoop/mapred/FairSchedulerServlet.java?rev=826566&r1=826565&r2=826566&view=diff
==============================================================================
--- hadoop/mapreduce/branches/branch-0.21/src/contrib/fairscheduler/src/java/org/apache/hadoop/mapred/FairSchedulerServlet.java (original)
+++ hadoop/mapreduce/branches/branch-0.21/src/contrib/fairscheduler/src/java/org/apache/hadoop/mapred/FairSchedulerServlet.java Mon Oct 19 00:19:23 2009
@@ -18,7 +18,9 @@
package org.apache.hadoop.mapred;
+import java.io.ByteArrayOutputStream;
import java.io.IOException;
+import java.io.OutputStream;
import java.io.PrintWriter;
import java.text.DateFormat;
import java.text.SimpleDateFormat;
@@ -118,7 +120,12 @@
}
// Print out the normal response
response.setContentType("text/html");
- PrintWriter out = new PrintWriter(response.getOutputStream());
+
+ // Because the client may read arbitrarily slow, and we hold locks while
+ // the servlet outputs, we want to write to our own buffer which we know
+ // won't block.
+ ByteArrayOutputStream baos = new ByteArrayOutputStream();
+ PrintWriter out = new PrintWriter(baos);
String hostname = StringUtils.simpleHostname(
jobTracker.getJobTrackerMachine());
out.print("<html><head>");
@@ -132,6 +139,11 @@
showJobs(out, advancedView);
out.print("</body></html>\n");
out.close();
+
+ // Flush our buffer to the real servlet output
+ OutputStream servletOut = response.getOutputStream();
+ baos.writeTo(servletOut);
+ servletOut.close();
}
/**
@@ -202,55 +214,57 @@
out.print("<th>Finished</th><th>Running</th><th>Fair Share</th>" +
(advancedView ? "<th>Weight</th>" : ""));
out.print("</tr>\n");
- Collection<JobInProgress> runningJobs = jobTracker.getRunningJobs();
- synchronized (scheduler) {
- for (JobInProgress job: runningJobs) {
- JobProfile profile = job.getProfile();
- JobInfo info = scheduler.infos.get(job);
- if (info == null) { // Job finished, but let's show 0's for info
- info = new JobInfo(null, null);
- }
- out.print("<tr>\n");
- out.printf("<td>%s</td>\n", DATE_FORMAT.format(
- new Date(job.getStartTime())));
- out.printf("<td><a href=\"jobdetails.jsp?jobid=%s\">%s</a></td>",
- profile.getJobID(), profile.getJobID());
- out.printf("<td>%s</td>\n", profile.getUser());
- out.printf("<td>%s</td>\n", profile.getJobName());
- if (JSPUtil.privateActionsAllowed()) {
- out.printf("<td>%s</td>\n", generateSelect(scheduler
- .getPoolManager().getPoolNames(), scheduler.getPoolManager()
- .getPoolName(job), "/scheduler?setPool=<CHOICE>&jobid="
- + profile.getJobID() + (advancedView ? "&advanced" : "")));
- out.printf("<td>%s</td>\n", generateSelect(Arrays
- .asList(new String[] { "VERY_LOW", "LOW", "NORMAL", "HIGH",
- "VERY_HIGH" }), job.getPriority().toString(),
- "/scheduler?setPriority=<CHOICE>&jobid=" + profile.getJobID()
- + (advancedView ? "&advanced" : "")));
- } else {
- out.printf("<td>%s</td>\n", scheduler.getPoolManager().getPoolName(job));
- out.printf("<td>%s</td>\n", job.getPriority().toString());
- }
- Pool pool = scheduler.getPoolManager().getPool(job);
- String mapShare = (pool.getSchedulingMode() == SchedulingMode.FAIR) ?
- String.format("%.1f", info.mapSchedulable.getFairShare()) : "NA";
- out.printf("<td>%d / %d</td><td>%d</td><td>%s</td>\n",
- job.finishedMaps(), job.desiredMaps(),
- info.mapSchedulable.getRunningTasks(),
- mapShare);
- if (advancedView) {
- out.printf("<td>%.1f</td>\n", info.mapSchedulable.getWeight());
- }
- String reduceShare = (pool.getSchedulingMode() == SchedulingMode.FAIR) ?
- String.format("%.1f", info.reduceSchedulable.getFairShare()) : "NA";
- out.printf("<td>%d / %d</td><td>%d</td><td>%s</td>\n",
- job.finishedReduces(), job.desiredReduces(),
- info.reduceSchedulable.getRunningTasks(),
- reduceShare);
- if (advancedView) {
- out.printf("<td>%.1f</td>\n", info.reduceSchedulable.getWeight());
+ synchronized (jobTracker) {
+ Collection<JobInProgress> runningJobs = jobTracker.getRunningJobs();
+ synchronized (scheduler) {
+ for (JobInProgress job: runningJobs) {
+ JobProfile profile = job.getProfile();
+ JobInfo info = scheduler.infos.get(job);
+ if (info == null) { // Job finished, but let's show 0's for info
+ info = new JobInfo(null, null);
+ }
+ out.print("<tr>\n");
+ out.printf("<td>%s</td>\n", DATE_FORMAT.format(
+ new Date(job.getStartTime())));
+ out.printf("<td><a href=\"jobdetails.jsp?jobid=%s\">%s</a></td>",
+ profile.getJobID(), profile.getJobID());
+ out.printf("<td>%s</td>\n", profile.getUser());
+ out.printf("<td>%s</td>\n", profile.getJobName());
+ if (JSPUtil.privateActionsAllowed()) {
+ out.printf("<td>%s</td>\n", generateSelect(scheduler
+ .getPoolManager().getPoolNames(), scheduler.getPoolManager()
+ .getPoolName(job), "/scheduler?setPool=<CHOICE>&jobid="
+ + profile.getJobID() + (advancedView ? "&advanced" : "")));
+ out.printf("<td>%s</td>\n", generateSelect(Arrays
+ .asList(new String[] { "VERY_LOW", "LOW", "NORMAL", "HIGH",
+ "VERY_HIGH" }), job.getPriority().toString(),
+ "/scheduler?setPriority=<CHOICE>&jobid=" + profile.getJobID()
+ + (advancedView ? "&advanced" : "")));
+ } else {
+ out.printf("<td>%s</td>\n", scheduler.getPoolManager().getPoolName(job));
+ out.printf("<td>%s</td>\n", job.getPriority().toString());
+ }
+ Pool pool = scheduler.getPoolManager().getPool(job);
+ String mapShare = (pool.getSchedulingMode() == SchedulingMode.FAIR) ?
+ String.format("%.1f", info.mapSchedulable.getFairShare()) : "NA";
+ out.printf("<td>%d / %d</td><td>%d</td><td>%s</td>\n",
+ job.finishedMaps(), job.desiredMaps(),
+ info.mapSchedulable.getRunningTasks(),
+ mapShare);
+ if (advancedView) {
+ out.printf("<td>%.1f</td>\n", info.mapSchedulable.getWeight());
+ }
+ String reduceShare = (pool.getSchedulingMode() == SchedulingMode.FAIR) ?
+ String.format("%.1f", info.reduceSchedulable.getFairShare()) : "NA";
+ out.printf("<td>%d / %d</td><td>%d</td><td>%s</td>\n",
+ job.finishedReduces(), job.desiredReduces(),
+ info.reduceSchedulable.getRunningTasks(),
+ reduceShare);
+ if (advancedView) {
+ out.printf("<td>%.1f</td>\n", info.reduceSchedulable.getWeight());
+ }
+ out.print("</tr>\n");
}
- out.print("</tr>\n");
}
}
out.print("</table>\n");