diff --git a/src/applications/cache/spec/PhabricatorDataCacheSpec.php b/src/applications/cache/spec/PhabricatorDataCacheSpec.php
index 482af00d00..bf6a495f7f 100644
--- a/src/applications/cache/spec/PhabricatorDataCacheSpec.php
+++ b/src/applications/cache/spec/PhabricatorDataCacheSpec.php
@@ -1,139 +1,145 @@
 <?php
 
 final class PhabricatorDataCacheSpec extends PhabricatorCacheSpec {
 
   private $cacheSummary;
 
   public function setCacheSummary(array $cache_summary) {
     $this->cacheSummary = $cache_summary;
     return $this;
   }
 
   public function getCacheSummary() {
     return $this->cacheSummary;
   }
 
   public static function getActiveCacheSpec() {
     $spec = new PhabricatorDataCacheSpec();
 
     // NOTE: If APCu is installed, it reports that APC is installed.
     if (extension_loaded('apc') && !extension_loaded('apcu')) {
       $spec->initAPCSpec();
     } else if (extension_loaded('apcu')) {
       $spec->initAPCuSpec();
     } else {
       $spec->initNoneSpec();
     }
 
     return $spec;
   }
 
   private function initAPCSpec() {
     $this
       ->setName(pht('APC User Cache'))
       ->setVersion(phpversion('apc'));
 
     if (ini_get('apc.enabled')) {
       $this
         ->setIsEnabled(true)
         ->setClearCacheCallback('apc_clear_cache');
       $this->initAPCCommonSpec();
     } else {
       $this->setIsEnabled(false);
       $this->raiseEnableAPCIssue();
     }
   }
 
   private function initAPCuSpec() {
     $this
       ->setName(pht('APCu'))
       ->setVersion(phpversion('apcu'));
 
     if (ini_get('apc.enabled')) {
+      if (function_exists('apcu_clear_cache')) {
+        $clear_callback = 'apcu_clear_cache';
+      } else {
+        $clear_callback = 'apc_clear_cache';
+      }
+
       $this
         ->setIsEnabled(true)
-        ->setClearCacheCallback('apc_clear_cache');
+        ->setClearCacheCallback($clear_callback);
       $this->initAPCCommonSpec();
     } else {
       $this->setIsEnabled(false);
       $this->raiseEnableAPCIssue();
     }
   }
 
   private function initNoneSpec() {
     if (version_compare(phpversion(), '5.5', '>=')) {
       $message = pht(
         'Installing the "APCu" PHP extension will improve performance. '.
         'This extension is strongly recommended. Without it, Phabricator '.
         'must rely on a very inefficient disk-based cache.');
 
       $this
         ->newIssue('extension.apcu')
         ->setShortName(pht('APCu'))
         ->setName(pht('PHP Extension "APCu" Not Installed'))
         ->setMessage($message)
         ->addPHPExtension('apcu');
     } else {
       $this->raiseInstallAPCIssue();
     }
   }
 
   private function initAPCCommonSpec() {
     $state = array();
 
     if (function_exists('apcu_sma_info')) {
       $mem = apcu_sma_info();
       $info = apcu_cache_info();
     } else if (function_exists('apc_sma_info')) {
       $mem = apc_sma_info();
       $info = apc_cache_info('user');
     } else {
       $mem = null;
     }
 
     if ($mem) {
       $this->setTotalMemory($mem['num_seg'] * $mem['seg_size']);
 
       $this->setUsedMemory($info['mem_size']);
       $this->setEntryCount(count($info['cache_list']));
 
       $cache = $info['cache_list'];
       $state = array();
       foreach ($cache as $item) {
         $info = idx($item, 'info', '<unknown-key>');
         $key = self::getKeyPattern($info);
         if (empty($state[$key])) {
           $state[$key] = array(
             'max' => 0,
             'total' => 0,
             'count' => 0,
           );
         }
         $state[$key]['max'] = max($state[$key]['max'], $item['mem_size']);
         $state[$key]['total'] += $item['mem_size'];
         $state[$key]['count']++;
       }
     }
 
     $this->setCacheSummary($state);
   }
 
   private static function getKeyPattern($key) {
     // If this key isn't in the current cache namespace, don't reveal any
     // information about it.
     $namespace = PhabricatorEnv::getEnvConfig('phabricator.cache-namespace');
     if (strncmp($key, $namespace.':', strlen($namespace) + 1)) {
       return '<other-namespace>';
     }
 
     $key = preg_replace('/(?<![a-zA-Z])\d+(?![a-zA-Z])/', 'N', $key);
     $key = preg_replace('/PHID-[A-Z]{4}-[a-z0-9]{20}/', 'PHID', $key);
 
     // TODO: We should probably standardize how digests get embedded into cache
     // keys to make this rule more generic.
     $key = preg_replace('/:celerity:.*$/', ':celerity:X', $key);
     $key = preg_replace('/:pkcs8:.*$/', ':pkcs8:X', $key);
 
     return $key;
   }
 }