38 

    39 #ifndef _WIN32

    40 #include <sys/mman.h>

    41 #include <pthread.h>

    42 #endif

    43 

  1212 #ifdef MADV_POPULATE_READ

  1213 

  1214 typedef struct {

  1215     void * mmap_address;

  1216     size_t length;

  1217 } mmap_info;

  1218 

  1219 static void _mmap_populate(mmap_info *info) {

  1220     /* We explicitly does not check the return value as we don't care about it.

  1221      * the madvise is here to help performance and we don't care if it fails

  1222      * (for example because the mapping is no longer valid) */

  1223     void * mmap_address = info->mmap_address;

  1224     size_t length = info->length;

  1225     free(info);

  1226     madvise(mmap_address, length, MADV_POPULATE_READ);

  1227 }

  1228 

  1229 static PyObject *background_mmap_populate(PyObject *self, PyObject *mmap) {

  1230     Py_buffer b;

  1231     pthread_t thread_id;

  1232     mmap_info *info;

  1233     if (PyObject_GetBuffer(mmap, &b, PyBUF_CONTIG_RO | PyBUF_C_CONTIGUOUS) == -1) {

  1234         return NULL;

  1235     }

  1236     info = (mmap_info *)malloc(sizeof(mmap_info));

  1237     info->mmap_address=b.buf;

  1238     info->length=b.len;

  1239     /* note: for very large map, we could spin multiple thread populating

  1240      * different area */

  1241     pthread_create(&thread_id, NULL, (void *) &_mmap_populate, info);

  1242     /* We don't keep track of this thread as it is fine for it to die when we

  1243      * exit. */

  1244     pthread_detach(thread_id);

  1245     /* We release the PyBuffer in the main thread to let the object be garbage

  1246      * collected as soon as possible. This might result in the memory map being

  1247      * closed while the background thread is working. That will result in a

  1248      * error in the background thread we can ignore. */

  1249     PyBuffer_Release(&b);

  1250 	Py_RETURN_NONE;

  1251 }

  1252 

  1253 #endif

  1254 

  1289 #ifdef MADV_POPULATE_READ

  1290 	{"background_mmap_populate", (PyCFunction)background_mmap_populate, METH_O,

  1291 	 "populate a mmap in the background\n"},

  1292 #endif