4998 // Remap a block of memory. |
4998 // Remap a block of memory. |
4999 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, |
4999 char* os::pd_remap_memory(int fd, const char* file_name, size_t file_offset, |
5000 char *addr, size_t bytes, bool read_only, |
5000 char *addr, size_t bytes, bool read_only, |
5001 bool allow_exec) { |
5001 bool allow_exec) { |
5002 // This OS does not allow existing memory maps to be remapped so we |
5002 // This OS does not allow existing memory maps to be remapped so we |
5003 // have to unmap the memory before we remap it. |
5003 // would have to unmap the memory before we remap it. |
5004 if (!os::unmap_memory(addr, bytes)) { |
5004 |
5005 return NULL; |
5005 // Because there is a small window between unmapping memory and mapping |
5006 } |
5006 // it in again with different protections, CDS archives are mapped RW |
5007 |
5007 // on windows, so this function isn't called. |
5008 // There is a very small theoretical window between the unmap_memory() |
5008 ShouldNotReachHere(); |
5009 // call above and the map_memory() call below where a thread in native |
5009 return NULL; |
5010 // code may be able to access an address that is no longer mapped. |
|
5011 |
|
5012 return os::map_memory(fd, file_name, file_offset, addr, bytes, |
|
5013 read_only, allow_exec); |
|
5014 } |
5010 } |
5015 |
5011 |
5016 |
5012 |
5017 // Unmap a block of memory. |
5013 // Unmap a block of memory. |
5018 // Returns true=success, otherwise false. |
5014 // Returns true=success, otherwise false. |