Author: markt
Date: Wed Oct 3 10:00:21 2012
New Revision: 1393381
URL: http://svn.apache.org/viewvc?rev=1393381&view=rev
Log:
Implement cache expiry during getResource()
Modified:
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/Cache.java
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/LocalStrings.properties
Modified:
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/Cache.java
URL:
http://svn.apache.org/viewvc/tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/Cache.java?rev=1393381&r1=1393380&r2=1393381&view=diff
==============================================================================
---
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/Cache.java
(original)
+++
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/Cache.java
Wed Oct 3 10:00:21 2012
@@ -38,7 +38,8 @@ public class Cache {
// based on profiler data.
private static final long CACHE_ENTRY_SIZE = 500;
- private static final long TARGET_FREE_PERCENT = 5;
+ private static final long TARGET_FREE_PERCENT_GET = 5;
+ private static final long TARGET_FREE_PERCENT_BACKGROUND = 10;
private final StandardRoot root;
private final AtomicLong size = new AtomicLong(0);
@@ -83,7 +84,20 @@ public class Cache {
size.addAndGet(delta);
if (size.get() > maxSize) {
- // TODO make room
+ // Process resources unordered for speed. Trades cache
+ // efficiency (younger entries may be evicted before older
+ // ones) for speed since this is on the critical path for
+ // request processing
+ long targetSize =
+ maxSize * (100 - TARGET_FREE_PERCENT_GET) / 100;
+ long newSize = evict(
+ targetSize, resourceCache.values().iterator());
+ if (newSize > maxSize) {
+ // Unable to create sufficient space for this resource
+ // Remove it from the cache
+ removeCacheEntry(path);
+ log.warn(sm.getString("cache.addFail"));
+ }
}
} else {
// Another thread added the entry to the cache
@@ -96,19 +110,34 @@ public class Cache {
}
protected void backgroundProcess() {
- long targetSize = maxSize * (100 - TARGET_FREE_PERCENT) / 100;
-
- long now = System.currentTimeMillis();
-
// Create an ordered set of all cached resources with the least
recently
- // used first.
+ // used first. This is a background process so we can afford to take
the
+ // time to order the elements first
TreeSet<CachedResource> orderedResources =
new TreeSet<>(new EvictionOrder());
orderedResources.addAll(resourceCache.values());
Iterator<CachedResource> iter = orderedResources.iterator();
- while (targetSize > size.get() && iter.hasNext()) {
+ long targetSize =
+ maxSize * (100 - TARGET_FREE_PERCENT_BACKGROUND) / 100;
+ long newSize = evict(targetSize, iter);
+
+ if (targetSize > newSize) {
+ log.info(sm.getString("cache.backgroundEvictFail",
+ Long.valueOf(TARGET_FREE_PERCENT_BACKGROUND),
+ root.getContext().getName(),
+ Long.valueOf(newSize / 1024)));
+ }
+ }
+
+ private long evict(long targetSize, Iterator<CachedResource> iter) {
+
+ long now = System.currentTimeMillis();
+
+ long newSize = size.get();
+
+ while (targetSize > newSize && iter.hasNext()) {
CachedResource resource = iter.next();
// Don't expire anything that has been checked within the TTL
@@ -118,15 +147,11 @@ public class Cache {
// Remove the entry from the cache
removeCacheEntry(resource.getWebappPath());
- }
- long cacheSize = size.get();
- if (targetSize > cacheSize) {
- log.info(sm.getString("cache.backgroundEvict",
- Long.valueOf(TARGET_FREE_PERCENT),
- root.getContext().getName(),
- Long.valueOf(cacheSize / 1024)));
+ newSize = size.get();
}
+
+ return newSize;
}
private void removeCacheEntry(String path) {
Modified:
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/LocalStrings.properties
URL:
http://svn.apache.org/viewvc/tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/LocalStrings.properties?rev=1393381&r1=1393380&r2=1393381&view=diff
==============================================================================
---
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/LocalStrings.properties
(original)
+++
tomcat/sandbox/trunk-resources/java/org/apache/catalina/webresources/LocalStrings.properties
Wed Oct 3 10:00:21 2012
@@ -16,7 +16,8 @@
abstractResource.getContentFail=Unable to return [{0}] as a byte array
abstractResource.getContentTooLarge=Unable to return [{0}] as a byte array
since the resource is [{1}] bytes in size which is larger than the maximum size
of a byte array
-cache.backgroundEvict=The background cache eviction process was unable to free
[{0}] percent of the cache for Context [{1}] - consider increasing the maximum
size of the cache. After eviction approximately [{2}] KB of data remained in
the cache.
+cache.addFail=Unable to add the resource at [{0}] to the cache because there
was insufficient free space available after evicting expired cache entries -
consider increasing the maximum size of the cache
+cache.backgroundEvictFail=The background cache eviction process was unable to
free [{0}] percent of the cache for Context [{1}] - consider increasing the
maximum size of the cache. After eviction approximately [{2}] KB of data
remained in the cache.
dirResourceSet.writeExists=The target of the write already exists
dirResourceSet.writeNpe=The input stream may not be null
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