NAME

       memkind_pmem - file-backed memory memkind operations.
       Note:  This  is  EXPERIMENTAL  API.  The  functionality  and the header file itself can be
       changed (including non-backward compatible changes) or removed.

SYNOPSIS

       int memkind_pmem_create(struct memkind *kind, struct memkind_ops *ops, const char *name);
       int memkind_pmem_destroy(struct memkind *kind);
       void *memkind_pmem_mmap(struct memkind *kind, void *addr, size_t size);
       int memkind_pmem_get_mmap_flags(struct memkind *kind, int *flags);
       int memkind_pmem_validate_dir(const char *dir);

DESCRIPTION

       The pmem memory memkind operations enable  memory  kinds  built  on  memory-mapped  files.
       These  support  traditional  volatile memory allocation in a fashion similar to libvmem(3)
       library.  It uses the mmap(2) system call to create  a  pool  of  volatile  memory.   Such
       memory  may have different attributes, depending on the file system containing the memory-
       mapped files.  (See also http://pmem.io/pmdk/libvmem).

       The pmem kinds are most useful when used with DAX (direct mapping of  persistent  memory),
       which  is  memory-addressable  persistent  storage that supports load/store access without
       being paged via the system page cache.  A Persistent Memory-aware file system is typically
       used to provide this type of access.

       The  most  convenient  way  to  create  pmem  kinds  is  to  use  memkind_create_pmem() or
       memkind_create_pmem_with_config() (see memkind(3)).

       memkind_pmem_create() is an implementation of the memkind  "create"  operation  for  file-
       backed  memory  kinds.  This allocates a space for some pmem-specific metadata, then calls
       memkind_arena_create() (see memkind_arena(3))

       memkind_pmem_destroy() is an implementation of the memkind "destroy" operation  for  file-
       backed    memory   kinds.    This   releases   all   of   the   resources   allocated   by
       memkind_pmem_create() and allows the file system space to be reclaimed.

       memkind_pmem_mmap() allocates the file system space for a  block  of  size  bytes  in  the
       memory-mapped  file  associated  with  given  kind.  The addr hint is ignored.  The return
       value is the address of mapped memory region or MAP_FAILED in the case of an error.

       memkind_pmem_get_mmap_flags() sets flags to MAP_SHARED.  See mmap(2) for more  information
       about these flags.

       memkind_pmem_validate_dir()  returns  zero  if file created in specified pmem_dir supports
       DAX (direct mapping of persistent memory) or an error code from the ERRORS if not.

       MEMKIND_PMEM_CHUNK_SIZE
              The size of the PMEM chunk size.

COPYRIGHT

       Copyright (C) 2015 - 2020 Intel Corporation. All rights reserved.

SEE ALSO

       memkind(3),  memkind_arena(3),  memkind_default(3),  memkind_hbw(3),   memkind_hugetlb(3),
       libvmem(3), jemalloc(3), mbind(2), mmap(2)