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YARN-6571. Fix JavaDoc issues in SchedulingPolicy

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(Contributed by Weiwei Yang via Daniel Templeton)
This commit is contained in:
Daniel Templeton 2017-05-10 14:30:34 -07:00
parent 3873904a94
commit e7654c4a1f
1 changed files with 30 additions and 8 deletions
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34
hadoop-yarn-project/hadoop-yarn/hadoop-yarn-server/hadoop-yarn-server-resourcemanager/src/main/java/org/apache/hadoop/yarn/server/resourcemanager/scheduler/fair/SchedulingPolicy.java
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@ -33,6 +33,21 @@
import java.util.Comparator;
import java.util.concurrent.ConcurrentHashMap;
/**
* The SchedulingPolicy is used by the fair scheduler mainly to determine
* what a queue's fair share and steady fair share should be as well as
* calculating available headroom. This determines how resources can be
* shared between running applications within a queue.
* <p>
* Every queue has a policy, including parents and children. If a child
* queue doesn't specify one, it inherits the parent's policy.
* The policy for a child queue must be compatible with the policy of
* the parent queue; there are some combinations that aren't allowed.
* See {@link SchedulingPolicy#isChildPolicyAllowed(SchedulingPolicy)}.
* The policy for a queue is specified by setting property
* <i>schedulingPolicy</i> in the fair scheduler configuration file.
* The default policy is {@link FairSharePolicy} if not specified.
*/
@Public
@Evolving
public abstract class SchedulingPolicy {
@ -43,9 +58,14 @@ public abstract class SchedulingPolicy {
getInstance(FairSharePolicy.class);
/**
* Returns a {@link SchedulingPolicy} instance corresponding to the passed clazz
* Returns a {@link SchedulingPolicy} instance corresponding
* to the passed clazz.
*
* @param clazz a class that extends {@link SchedulingPolicy}
* @return a {@link SchedulingPolicy} instance
*/
public static SchedulingPolicy getInstance(Class<? extends SchedulingPolicy> clazz) {
public static SchedulingPolicy getInstance(
Class<? extends SchedulingPolicy> clazz) {
SchedulingPolicy policy = ReflectionUtils.newInstance(clazz, null);
SchedulingPolicy policyRet = instances.putIfAbsent(clazz, policy);
if(policyRet != null) {
@ -63,7 +83,9 @@ public static SchedulingPolicy getInstance(Class<? extends SchedulingPolicy> cla
* canonical class name of the {@link SchedulingPolicy}.
*
* @param policy canonical class name or "drf" or "fair" or "fifo"
* @return a {@link SchedulingPolicy} instance parsed from given policy
* @throws AllocationConfigurationException
*
*/
@SuppressWarnings("unchecked")
public static SchedulingPolicy parse(String policy)
@ -158,7 +180,7 @@ public abstract void computeSteadyShares(
Collection<? extends FSQueue> queues, Resource totalResources);
/**
* Check if the resource usage is over the fair share under this policy
* Check if the resource usage is over the fair share under this policy.
*
* @param usage {@link Resource} the resource usage
* @param fairShare {@link Resource} the fair share
@ -168,10 +190,10 @@ public abstract boolean checkIfUsageOverFairShare(
Resource usage, Resource fairShare);
/**
* Get headroom by calculating the min of <code>clusterAvailable</code> and
* (<code>queueFairShare</code> - <code>queueUsage</code>) resources that are
* Get headroom by calculating the min of {@code clusterAvailable} and
* ({@code queueFairShare} - {@code queueUsage}) resources that are
* applicable to this policy. For eg if only memory then leave other
* resources such as CPU to same as clusterAvailable.
* resources such as CPU to same as {@code clusterAvailable}.
*
* @param queueFairShare fairshare in the queue
* @param queueUsage resources used in the queue