NAME

       pmem2_vm_reservation_new(),  pmem2_vm_reservation_delete()  -  creates  or deletes an instance of virtual
       memory reservation

SYNOPSIS

              #include <libpmem2.h>

              struct pmem2_vm_reservation;
              int pmem2_vm_reservation_new(struct pmem2_vm_reservation **rsv_ptr,
                      void *addr, size_t size);
              int pmem2_vm_reservation_delete(struct pmem2_vm_reservation **rsv_ptr);

DESCRIPTION

       The pmem2_vm_reservation_new() function creates a new blank mapping in the virtual address space  of  the
       calling process.  Reservation serves as a placeholder of a given size on which sources can be mapped.

       For  the function to succeed, the addr must be either aligned to an appropriate allocation granularity or
       NULL, the size always has to be aligned to an appropriate allocation granularity.

       If the pmem2_vm_reservation_new() succeeds in creating  a  reservation,  it  instantiates  a  new  struct
       pmem2_vm_reservation  object  describing  the  reservation.   The pointer to this object is stored in the
       user-provided variable via the rsv_ptr pointer.  If the function fails, an appropriate error  value  will
       be returned.  For a list of possible return values please see RETURN VALUE

       After  instantiating  an  object via the pmem2_vm_reservation_new() function, it may be disposed of using
       the pmem2_vm_reservation_delete() function.

       The pmem2_vm_reservation_delete() function destroys the object describing the reservation and unmaps vir‐
       tual memory region the *struct pmem2_vm_reservation** had assigned during the  initialization.   For  the
       delete  function  to succeed, it is required that the reservation passed via the rsv_ptr pointer does not
       contain any mappings.

RETURN VALUE

       The pmem2_vm_reservation_new() and pmem2_vm_reservation_delete() functions return 0 on success or a nega‐
       tive error code on failure.

       The function returns 0 on success or a negative error code on failure.

ERRORS

       The pmem2_vm_reservation_new() function can fail with the following errors:

       • PMEM2_E_ADDRESS_UNALIGNED - argument addr is not aligned to the appropriate allocation granularity.

       • PMEM2_E_MAPPING_EXISTS - mapping already exists in the range (addr, addr + size).

       It can also return -EAGAIN, -ENOMEM from the underlying mmap(2) function and -ENOMEM in case of  insuffi‐
       cient memory to allocate an instance of struct pmem2_vm_reservation.

       The pmem2_vm_reservation_delete() function can fail with the following errors:

       • PMEM2_E_RESERVATION_NOT_EMPTY - reservation contains mappings.

       It can also return errors from the underlying munmap(2) function.

SEE ALSO

       pmem2_config_set_vm_reservation(3), libpmem2(7) and <https://pmem.io>

PMDK - pmem2 API version 1.0                       2021-09-24                        PMEM2_VM_RESERVATION_NEW(3)