src/hotspot/os/linux/osContainer_linux.cpp

*** 52,67 ****
--- 52,71 ----
   */
  #define PER_CPU_SHARES 1024
  
  bool  OSContainer::_is_initialized   = false;
  bool  OSContainer::_is_containerized = false;
+ int   OSContainer::_active_processor_count = 1;
  julong _unlimited_memory;
  
  class CgroupSubsystem: CHeapObj<mtInternal> {
   friend class OSContainer;
  
+ 
   private:
+     volatile jlong _next_check_counter;
+ 
      /* mountinfo contents */
      char *_root;
      char *_mount_point;
  
      /* Constructed subsystem directory */
*** 70,79 ****
--- 74,84 ----
   public:
      CgroupSubsystem(char *root, char *mountpoint) {
        _root = os::strdup(root);
        _mount_point = os::strdup(mountpoint);
        _path = NULL;
+       _next_check_counter = min_jlong;
      }
  
      /*
       * Set directory to subsystem specific files based
       * on the contents of the mountinfo and cgroup files.
*** 119,128 ****
--- 124,142 ----
          }
        }
      }
  
      char *subsystem_path() { return _path; }
+ 
+     bool check_cache_timeout() {
+       return os::elapsed_counter() > _next_check_counter;
+     }
+ 
+     void set_cache_timeout(jlong timeout) {
+       _next_check_counter = os::elapsed_counter() + timeout;
+     }
+     
  };
  
  class CgroupMemorySubsystem: CgroupSubsystem {
   friend class OSContainer;
  
*** 130,164 ****
      /* Some container runtimes set limits via cgroup
       * hierarchy. If set to true consider also memory.stat
       * file if everything else seems unlimited */
      bool _uses_mem_hierarchy;
      volatile jlong _memory_limit_in_bytes;
-     volatile jlong _next_check_counter;
  
   public:
      CgroupMemorySubsystem(char *root, char *mountpoint) : CgroupSubsystem::CgroupSubsystem(root, mountpoint) {
        _uses_mem_hierarchy = false;
        _memory_limit_in_bytes = -1;
-       _next_check_counter = min_jlong;
  
      }
  
      bool is_hierarchical() { return _uses_mem_hierarchy; }
      void set_hierarchical(bool value) { _uses_mem_hierarchy = value; }
  
-     bool should_check_memory_limit() {
-       return os::elapsed_counter() > _next_check_counter;
-     }
      jlong memory_limit_in_bytes() { return _memory_limit_in_bytes; }
      void set_memory_limit_in_bytes(jlong value) {
        _memory_limit_in_bytes = value;
        // max memory limit is unlikely to change, but we want to remain
        // responsive to configuration changes. A very short (20ms) grace time
        // between re-read avoids excessive overhead during startup without
        // significantly reducing the VMs ability to promptly react to reduced
        // memory availability
!       _next_check_counter = os::elapsed_counter() + (NANOSECS_PER_SEC/50);
      }
  
  };
  
  CgroupMemorySubsystem* memory = NULL;
--- 144,173 ----
      /* Some container runtimes set limits via cgroup
       * hierarchy. If set to true consider also memory.stat
       * file if everything else seems unlimited */
      bool _uses_mem_hierarchy;
      volatile jlong _memory_limit_in_bytes;
  
   public:
      CgroupMemorySubsystem(char *root, char *mountpoint) : CgroupSubsystem::CgroupSubsystem(root, mountpoint) {
        _uses_mem_hierarchy = false;
        _memory_limit_in_bytes = -1;
  
      }
  
      bool is_hierarchical() { return _uses_mem_hierarchy; }
      void set_hierarchical(bool value) { _uses_mem_hierarchy = value; }
  
      jlong memory_limit_in_bytes() { return _memory_limit_in_bytes; }
      void set_memory_limit_in_bytes(jlong value) {
        _memory_limit_in_bytes = value;
        // max memory limit is unlikely to change, but we want to remain
        // responsive to configuration changes. A very short (20ms) grace time
        // between re-read avoids excessive overhead during startup without
        // significantly reducing the VMs ability to promptly react to reduced
        // memory availability
!       set_cache_timeout(OSCONTAINER_CACHE_TIMEOUT);
      }
  
  };
  
  CgroupMemorySubsystem* memory = NULL;
*** 479,489 ****
   *    memory limit in bytes or
   *    -1 for unlimited
   *    OSCONTAINER_ERROR for not supported
   */
  jlong OSContainer::memory_limit_in_bytes() {
!   if (!memory->should_check_memory_limit()) {
      return memory->memory_limit_in_bytes();
    }
    jlong memory_limit = read_memory_limit_in_bytes();
    // Update CgroupMemorySubsystem to avoid re-reading container settings too often
    memory->set_memory_limit_in_bytes(memory_limit);
--- 488,498 ----
   *    memory limit in bytes or
   *    -1 for unlimited
   *    OSCONTAINER_ERROR for not supported
   */
  jlong OSContainer::memory_limit_in_bytes() {
!   if (!memory->check_cache_timeout()) {
      return memory->memory_limit_in_bytes();
    }
    jlong memory_limit = read_memory_limit_in_bytes();
    // Update CgroupMemorySubsystem to avoid re-reading container settings too often
    memory->set_memory_limit_in_bytes(memory_limit);
*** 615,624 ****
--- 624,641 ----
  int OSContainer::active_processor_count() {
    int quota_count = 0, share_count = 0;
    int cpu_count, limit_count;
    int result;
  
+   // We use a cache with a timeout to avoid performing expensive
+   // computations in the event this function is called frequently.
+   // [See 8227006].
+   if (!cpu->check_cache_timeout()) {
+     log_trace(os, container)("OSContainer::active_processor_count (cached): %d", OSContainer::_active_processor_count);
+     return OSContainer::_active_processor_count;
+   }
+ 
    cpu_count = limit_count = os::Linux::active_processor_count();
    int quota  = cpu_quota();
    int period = cpu_period();
    int share  = cpu_shares();
  
*** 647,656 ****
--- 664,678 ----
      limit_count = share_count;
    }
  
    result = MIN2(cpu_count, limit_count);
    log_trace(os, container)("OSContainer::active_processor_count: %d", result);
+ 
+   // Update the value and set the cache timeout to 20ms.
+   OSContainer::_active_processor_count = result;
+   cpu->set_cache_timeout(OSCONTAINER_CACHE_TIMEOUT);
+ 
    return result;
  }
  
  char * OSContainer::cpu_cpuset_cpus() {
    GET_CONTAINER_INFO_CPTR(cptr, cpuset, "/cpuset.cpus",