MEMKIND_PMEM(3)

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)