mono/io-layer/collection.c

   1 /*
   2  * collection.c:  Garbage collection for handles
   3  *
   4  * Author:
   5  *      Dick Porter (dick@ximian.com)
   6  *
   7  * (C) 2004 Novell, Inc.
   8  */
   9
  10 #include <config.h>
  11 #include <glib.h>
  12 #include <pthread.h>
  13 #include <signal.h>
  14 #include <sys/types.h>
  15 #include <unistd.h>
  16
  17 #include <mono/io-layer/wapi.h>
  18 #include <mono/io-layer/collection.h>
  19 #include <mono/io-layer/handles-private.h>
  20
  21 #undef DEBUG
  22
  23 static pthread_t collection_thread_id;
  24
  25 static gpointer collection_thread (gpointer args) G_GNUC_NORETURN;
  26 static gpointer collection_thread (gpointer unused G_GNUC_UNUSED)
  27 {
  28         struct timespec sleepytime;
  29
  30         sleepytime.tv_sec = _WAPI_HANDLE_COLLECTION_UPDATE_INTERVAL;
  31         sleepytime.tv_nsec = 0;
  32
  33         while (1) {
  34                 //_wapi_handle_dump ();
  35                 _wapi_handle_update_refs ();
  36                 nanosleep (&sleepytime, NULL);
  37         }
  38
  39 #ifndef __GNUC__
  40         /* Even though we tell gcc that this function doesn't return,
  41          * other compilers won't see that.
  42          */
  43         return(NULL);
  44 #endif
  45 }
  46
  47 void _wapi_collection_init (void)
  48 {
  49         pthread_attr_t attr;
  50         int ret;
  51
  52         ret = pthread_attr_init (&attr);
  53         g_assert (ret == 0);
  54
  55 #ifdef HAVE_PTHREAD_ATTR_SETSTACKSIZE
  56 #ifdef __FreeBSD__
  57         ret = pthread_attr_setstacksize (&attr, 65536);
  58 #else
  59         ret = pthread_attr_setstacksize (&attr, PTHREAD_STACK_MIN);
  60 #endif
  61         g_assert (ret == 0);
  62 #endif
  63
  64         ret = pthread_create (&collection_thread_id, &attr, collection_thread,
  65                               NULL);
  66         if (ret != 0) {
  67                 g_error ("%s: Couldn't create handle collection thread: %s",
  68                          __func__, g_strerror (ret));
  69         }
  70 }
  71
  72 void _wapi_handle_collect (void)
  73 {
  74         guint32 count = _wapi_shared_layout->collection_count;
  75         int i;
  76
  77 #ifdef DEBUG
  78         g_message ("%s: (%d) Starting a collection", __func__, getpid ());
  79 #endif
  80
  81         /* Become the collection master */
  82         _WAPI_HANDLE_COLLECTION_UNSAFE;
  83
  84 #ifdef DEBUG
  85         g_message ("%s: (%d) Master set", __func__, getpid ());
  86 #endif
  87
  88         /* If count has changed, someone else jumped in as master */
  89         if (count == _wapi_shared_layout->collection_count) {
  90                 for (i = 0; i < _WAPI_HANDLE_INITIAL_COUNT; i++) {
  91                         struct _WapiHandleShared *shared;
  92                         struct _WapiHandleSharedMetadata *meta;
  93                         guint32 too_old = (guint32)(time(NULL) & 0xFFFFFFFF) - _WAPI_HANDLE_COLLECTION_EXPIRED_INTERVAL;
  94
  95                         meta = &_wapi_shared_layout->metadata[i];
  96                         if (meta->timestamp < too_old && meta->offset != 0) {
  97 #ifdef DEBUG
  98                                 g_message ("%s: (%d) Deleting metadata slot 0x%x handle 0x%x", __func__, getpid (), i, meta->offset);
  99 #endif
 100                                 memset (&_wapi_shared_layout->handles[meta->offset], '\0', sizeof(struct _WapiHandleShared));
 101                                 memset (&_wapi_shared_layout->metadata[i], '\0', sizeof(struct _WapiHandleSharedMetadata));
 102                         }
 103
 104                         /* Need to blank any handles data that is no
 105                          * longer pointed to by a metadata entry too
 106                          */
 107                         shared = &_wapi_shared_layout->handles[i];
 108                         if (shared->stale == TRUE) {
 109 #ifdef DEBUG
 110                                 g_message ("%s: (%d) Deleting stale handle 0x%x", __func__, getpid (), i);
 111 #endif
 112                                 memset (&_wapi_shared_layout->handles[i], '\0',
 113                                         sizeof(struct _WapiHandleShared));
 114                         }
 115                 }
 116
 117                 for (i = 0; i < _wapi_fileshare_layout->hwm; i++) {
 118                         struct _WapiFileShare *file_share = &_wapi_fileshare_layout->share_info[i];
 119                         guint32 too_old = (guint32)(time(NULL) & 0xFFFFFFFF) - _WAPI_HANDLE_COLLECTION_EXPIRED_INTERVAL;
 120
 121                         if (file_share->timestamp < too_old) {
 122                                 memset (file_share, '\0',
 123                                         sizeof(struct _WapiFileShare));
 124                         }
 125                 }
 126
 127                 InterlockedIncrement (&_wapi_shared_layout->collection_count);
 128         }
 129
 130         _WAPI_HANDLE_COLLECTION_SAFE;
 131
 132 #ifdef DEBUG
 133         g_message ("%s: (%d) Collection done", __func__, getpid ());
 134 #endif
 135 }