Remove usage of volatile keyword

cmd/traffic_manager/traffic_manager.cc

@@ -57,10 +57,15 @@
 #include <sys/capability.h>
 #endif
 #include <grp.h>
+#include <atomic>
 
 #define FD_THROTTLE_HEADROOM (128 + 64) // TODO: consolidate with THROTTLE_FD_HEADROOM
 #define DIAGS_LOG_FILENAME "manager.log"
 
+#if ATOMIC_INT_LOCK_FREE != 2
+#error "Need lock free std::atomic<int>"
+#endif
+
 // These globals are still referenced directly by management API.
 LocalManager *lmgmt = nullptr;
 FileManager *configFiles;
@@ -100,7 +105,7 @@ static void SignalHandler(int sig);
 static void SignalAlrmHandler(int sig);
 #endif
 
-static volatile int sigHupNotifier = 0;
+static std::atomic<int> sigHupNotifier;
 static void SigChldHandler(int sig);
 
 static void
@@ -704,7 +709,7 @@ main(int argc, const char **argv)
     rotateLogs();
 
     // Check for a SIGHUP
-    if (sigHupNotifier != 0) {
+    if (sigHupNotifier) {
       mgmt_log("[main] Reading Configuration Files due to SIGHUP\n");
       Reconfigure();
       sigHupNotifier = 0;

example/remap/remap.cc

@@ -35,6 +35,8 @@
 #include <cstdarg>
 #include <cerrno>
 #include <pthread.h>
+#include <cstdint>
+#include <atomic>
 
 #include "ts/ink_defs.h"
 #include "ts/ts.h"
@@ -210,8 +212,8 @@ TSRemapDeleteInstance(void *ih)
   delete ri;
 }
 
-static volatile unsigned long processing_counter = 0; // sequential counter
-static int arg_index                             = 0;
+static std::atomic<uint64_t> processing_counter; // sequential counter
+static int arg_index;
 
 /* -------------------------- TSRemapDoRemap -------------------------------- */
 TSRemapStatus
@@ -221,8 +223,7 @@ TSRemapDoRemap(void *ih, TSHttpTxn rh, TSRemapRequestInfo *rri)
   const char *temp2;
   int len, len2, port;
   TSMLoc cfield;
-  unsigned long _processing_counter =
-    ++processing_counter; // one more function call (in real life use mutex to protect this counter)
+  uint64_t _processing_counter = processing_counter++;
 
   remap_entry *ri = (remap_entry *)ih;
   TSDebug(PLUGIN_NAME, "enter");
@@ -275,7 +276,7 @@ TSRemapDoRemap(void *ih, TSHttpTxn rh, TSRemapRequestInfo *rri)
     TSHttpTxnArgSet((TSHttpTxn)rh, arg_index, (void *)_processing_counter); // save counter
   }
   // How to cancel request processing and return error message to the client
-  // We wiil do it each other request
+  // We wiil do it every other request
   if (_processing_counter & 1) {
     char *tmp                   = (char *)TSmalloc(256);
     static int my_local_counter = 0;

iocore/aio/AIO.cc

@@ -39,7 +39,7 @@ int ts_config_with_inkdiskio = 0;
 /* structure to hold information about each file descriptor */
 AIO_Reqs *aio_reqs[MAX_DISKS_POSSIBLE];
 /* number of unique file descriptors in the aio_reqs array */
-volatile int num_filedes = 1;
+int num_filedes = 1;
 
 // acquire this mutex before inserting a new entry in the aio_reqs array.
 // Don't need to acquire this for searching the array

iocore/aio/I_AIO.h

@@ -70,10 +70,10 @@ typedef struct io_event ink_io_event_t;
 #else
 
 struct ink_aiocb {
-  int aio_fildes         = 0;
-  volatile void *aio_buf = nullptr; /* buffer location */
-  size_t aio_nbytes      = 0;       /* length of transfer */
-  off_t aio_offset       = 0;       /* file offset */
+  int aio_fildes    = 0;
+  void *aio_buf     = nullptr; /* buffer location */
+  size_t aio_nbytes = 0;       /* length of transfer */
+  off_t aio_offset  = 0;       /* file offset */
 
   int aio_reqprio    = 0; /* request priority offset */
   int aio_lio_opcode = 0; /* listio operation */

iocore/aio/P_AIO.h

@@ -122,11 +122,11 @@ struct AIO_Reqs {
   InkAtomicList aio_temp_list;
   ink_mutex aio_mutex;
   ink_cond aio_cond;
-  int index;            /* position of this struct in the aio_reqs array */
-  volatile int pending; /* number of outstanding requests on the disk */
-  volatile int queued;  /* total number of aio_todo and http_todo requests */
-  volatile int filedes; /* the file descriptor for the requests */
-  volatile int requests_queued;
+  int index;   /* position of this struct in the aio_reqs array */
+  int pending; /* number of outstanding requests on the disk */
+  int queued;  /* total number of aio_todo and http_todo requests */
+  int filedes; /* the file descriptor for the requests */
+  int requests_queued;
 };
 
 #endif // AIO_MODE == AIO_MODE_NATIVE

iocore/aio/test_AIO.cc

@@ -52,7 +52,7 @@ enum {
 };
 
 struct AIO_Device;
-volatile int n_accessors = 0;
+int n_accessors = 0;
 int orig_n_accessors;
 AIO_Device *dev[MAX_DISK_THREADS];
 

iocore/cache/Cache.cc

@@ -87,26 +87,26 @@ int cache_config_compatibility_4_2_0_fixup = 1;
 
 // Globals
 
-RecRawStatBlock *cache_rsb          = nullptr;
-Cache *theStreamCache               = nullptr;
-Cache *theCache                     = nullptr;
-CacheDisk **gdisks                  = nullptr;
-int gndisks                         = 0;
-static volatile int initialize_disk = 0;
+RecRawStatBlock *cache_rsb = nullptr;
+Cache *theStreamCache      = nullptr;
+Cache *theCache            = nullptr;
+CacheDisk **gdisks         = nullptr;
+int gndisks                = 0;
+static int initialize_disk;
 Cache *caches[NUM_CACHE_FRAG_TYPES] = {nullptr};
 CacheSync *cacheDirSync             = nullptr;
 Store theCacheStore;
-volatile int CacheProcessor::initialized      = CACHE_INITIALIZING;
-volatile uint32_t CacheProcessor::cache_ready = 0;
-volatile int CacheProcessor::start_done       = 0;
-bool CacheProcessor::clear                    = false;
-bool CacheProcessor::fix                      = false;
-bool CacheProcessor::check                    = false;
-int CacheProcessor::start_internal_flags      = 0;
-int CacheProcessor::auto_clear_flag           = 0;
+int CacheProcessor::initialized          = CACHE_INITIALIZING;
+uint32_t CacheProcessor::cache_ready     = 0;
+int CacheProcessor::start_done           = 0;
+bool CacheProcessor::clear               = false;
+bool CacheProcessor::fix                 = false;
+bool CacheProcessor::check               = false;
+int CacheProcessor::start_internal_flags = 0;
+int CacheProcessor::auto_clear_flag      = 0;
 CacheProcessor cacheProcessor;
-Vol **gvol         = nullptr;
-volatile int gnvol = 0;
+Vol **gvol = nullptr;
+int gnvol  = 0;
 ClassAllocator<CacheVC> cacheVConnectionAllocator("cacheVConnection");
 ClassAllocator<EvacuationBlock> evacuationBlockAllocator("evacuationBlock");
 ClassAllocator<CacheRemoveCont> cacheRemoveContAllocator("cacheRemoveCont");
@@ -277,7 +277,7 @@ static int
 update_cache_config(const char * /* name ATS_UNUSED */, RecDataT /* data_type ATS_UNUSED */, RecData data,
                     void * /* cookie ATS_UNUSED */)
 {
-  volatile int new_value         = validate_rww(data.rec_int);
+  int new_value                  = validate_rww(data.rec_int);
   cache_config_read_while_writer = new_value;
 
   return 0;

iocore/cache/CacheHosting.cc

@@ -770,7 +770,7 @@ extern CacheDisk **gdisks;
 extern Queue<CacheVol> cp_list;
 extern int cp_list_len;
 extern ConfigVolumes config_volumes;
-extern volatile int gnvol;
+extern int gnvol;
 
 extern void cplist_init();
 extern int cplist_reconfigure();

iocore/cache/CachePagesInternal.cc

@@ -52,7 +52,7 @@ extern ShowCacheInternal *theshowcacheInternal;
 Action *register_ShowCacheInternal(Continuation *c, HTTPHdr *h);
 
 extern Vol **gvol;
-extern volatile int gnvol;
+extern int gnvol;
 
 // Stat Pages
 ShowCacheInternal *theshowcacheInternal = nullptr;

iocore/cache/I_Cache.h

@@ -150,9 +150,9 @@ struct CacheProcessor : public Processor {
     return wait_for_cache;
   }
 
-  static volatile uint32_t cache_ready;
-  static volatile int initialized;
-  static volatile int start_done;
+  static uint32_t cache_ready;
+  static int initialized;
+  static int start_done;
   static bool clear;
   static bool fix;
   static bool check;

iocore/cache/P_CacheDir.h

@@ -233,8 +233,8 @@ struct OpenDirEntry {
   uint16_t max_writers;                            // max number of simultaneous writers allowed
   bool dont_update_directory;                      // if set, the first_dir is not updated.
   bool move_resident_alt;                          // if set, single_doc_dir is inserted.
-  volatile bool reading_vec;                       // somebody is currently reading the vector
-  volatile bool writing_vec;                       // somebody is currently writing the vector
+  bool reading_vec;                                // somebody is currently reading the vector
+  bool writing_vec;                                // somebody is currently writing the vector
 
   LINK(OpenDirEntry, link);
 

iocore/cache/P_CacheHosting.h

@@ -49,8 +49,8 @@ struct CacheHostRecord {
 
   CacheType type;
   Vol **vols;
-  volatile int good_num_vols;
-  volatile int num_vols;
+  int good_num_vols;
+  int num_vols;
   int num_initialized;
   unsigned short *vol_hash_table;
   CacheVol **cp;

iocore/cache/P_CacheInternal.h

@@ -944,13 +944,13 @@ struct Vol;
 class CacheHostTable;
 
 struct Cache {
-  volatile int cache_read_done;
-  volatile int total_good_nvol;
-  volatile int total_nvol;
-  volatile int ready;
+  int cache_read_done;
+  int total_good_nvol;
+  int total_nvol;
+  int ready;
   int64_t cache_size; // in store block size
   CacheHostTable *hosttable;
-  volatile int total_initialized_vol;
+  int total_initialized_vol;
   CacheType scheme;
 
   int open(bool reconfigure, bool fix);

iocore/cache/P_CacheTest.h

@@ -50,7 +50,7 @@ struct PinnedDocTable : public Continuation {
 
 struct CacheTestHost {
   char *name;
-  volatile unsigned int xlast_cachable_id;
+  unsigned int xlast_cachable_id;
   double xprev_host_prob;
   double xnext_host_prob;
 

iocore/cache/P_CacheVol.h

@@ -302,7 +302,7 @@ struct Doc {
 // Global Data
 
 extern Vol **gvol;
-extern volatile int gnvol;
+extern int gnvol;
 extern ClassAllocator<OpenDirEntry> openDirEntryAllocator;
 extern ClassAllocator<EvacuationBlock> evacuationBlockAllocator;
 extern ClassAllocator<EvacuationKey> evacuationKeyAllocator;

iocore/eventsystem/I_Action.h

@@ -119,7 +119,7 @@ class Action
     machine.
 
   */
-  volatile int cancelled = false;
+  int cancelled = false;
 
   /**
     Cancels the asynchronous operation represented by this action.

iocore/eventsystem/I_EThread.h

@@ -52,7 +52,7 @@ enum ThreadType {
   DEDICATED,
 };
 
-extern volatile bool shutdown_event_system;
+extern bool shutdown_event_system;
 
 /**
   Event System specific type of thread.

iocore/eventsystem/I_EventProcessor.h

@@ -332,8 +332,8 @@ class EventProcessor : public Processor
   EThread *assign_thread(EventType etype);
 
   EThread *all_dthreads[MAX_EVENT_THREADS];
-  volatile int n_dthreads       = 0; // No. of dedicated threads
-  volatile int thread_data_used = 0;
+  int n_dthreads       = 0; // No. of dedicated threads
+  int thread_data_used = 0;
 
   /// Provide container style access to just the active threads, not the entire array.
   class active_threads_type

iocore/eventsystem/I_Lock.h

@@ -149,7 +149,6 @@
 
 class EThread;
 typedef EThread *EThreadPtr;
-typedef volatile EThreadPtr VolatileEThreadPtr;
 
 #if DEBUG
 inkcoreapi extern void lock_waiting(const SourceLocation &, const char *handler);
@@ -203,7 +202,7 @@ class ProxyMutex : public RefCountObj
     lock.  You must not modify or set this value directly.
 
   */
-  volatile EThreadPtr thread_holding;
+  EThreadPtr thread_holding;
 
   int nthread_holding;
 

iocore/eventsystem/UnixEThread.cc

@@ -38,7 +38,7 @@ struct AIOCallback;
 #define NO_HEARTBEAT -1
 #define THREAD_MAX_HEARTBEAT_MSECONDS 60
 
-volatile bool shutdown_event_system = false;
+bool shutdown_event_system = false;
 
 EThread::EThread()
 {

iocore/net/P_UnixNetState.h

@@ -44,7 +44,7 @@ class Event;
 class UnixNetVConnection;
 
 struct NetState {
-  volatile int enabled;
+  int enabled;
   VIO vio;
   Link<UnixNetVConnection> ready_link;
   SLink<UnixNetVConnection> enable_link;

iocore/net/P_UnixNetVConnection.h

@@ -223,7 +223,7 @@ class UnixNetVConnection : public NetVConnection
   UnixNetVConnection *migrateToCurrentThread(Continuation *c, EThread *t);
 
   Action action_;
-  volatile int closed;
+  int closed;
   NetState read;
   NetState write;
 

iocore/net/UnixNetAccept.cc

@@ -28,9 +28,8 @@
 #endif
 #define ROUNDUP(x, y) ((((x) + ((y)-1)) / (y)) * (y))
 
-using NetAcceptHandler      = int (NetAccept::*)(int, void *);
-volatile int dummy_volatile = 0;
-int accept_till_done        = 1;
+using NetAcceptHandler = int (NetAccept::*)(int, void *);
+int accept_till_done   = 1;
 
 std::vector<NetAccept *> naVec;
 static void

iocore/net/UnixNetProcessor.cc

@@ -29,7 +29,7 @@
 // For Stat Pages
 #include "StatPages.h"
 
-volatile int net_accept_number = 0;
+int net_accept_number = 0;
 extern std::vector<NetAccept *> naVec;
 NetProcessor::AcceptOptions const NetProcessor::DEFAULT_ACCEPT_OPTIONS;
 

lib/cppapi/Logger.cc

@@ -44,7 +44,7 @@ struct atscppapi::LoggerState : noncopyable {
   std::string filename_;
   bool add_timestamp_;
   bool rename_file_;
-  volatile Logger::LogLevel level_;
+  Logger::LogLevel level_;
   bool rolling_enabled_;
   int rolling_interval_seconds_;
   TSTextLogObject text_log_obj_;

lib/ts/BaseLogFile.h

@@ -219,10 +219,10 @@ class BaseLogFile
     LOG_FILE_COULD_NOT_OPEN_FILE,
   };
 
-  FILE *m_fp                        = nullptr;
-  long m_start_time                 = time(nullptr);
-  long m_end_time                   = 0L;
-  volatile uint64_t m_bytes_written = 0;
+  FILE *m_fp               = nullptr;
+  long m_start_time        = time(nullptr);
+  long m_end_time          = 0L;
+  uint64_t m_bytes_written = 0;
 
 private:
   // member functions

lib/ts/Diags.h

@@ -121,7 +121,7 @@ class Diags
   BaseLogFile *stderr_log;
 
   const unsigned int magic;
-  volatile DiagsConfigState config;
+  DiagsConfigState config;
   DiagsShowLocation show_location;
   DiagsCleanupFunc cleanup_func;