NAME¶

pmem2_config_set_vdm(), pmem2_memcpy_async(), pmem2_memmove_async(), pmem2_memset_async() - asynchronous data movement operations

SYNOPSIS¶

#define PMEM2_USE_MINIASYNC 1
#include <libpmem2.h>
struct pmem2_future;
int pmem2_config_set_vdm(struct pmem2_config *cfg, struct vdm *vdm);
struct pmem2_future pmem2_memcpy_async(struct pmem2_map *map,
    void *pmemdest, const void *src, size_t len, unsigned flags);
struct pmem2_future pmem2_memmove_async(struct pmem2_map *map, void *pmemdest, const void *src,
    size_t len, unsigned flags)
struct pmem2_future pmem2_memset_async(struct pmem2_map *map,
    void *pmemstr,  int c, size_t n, unsigned flags)
{

DESCRIPTION¶

To use those functions, you must have libminiasync installed. Those functions use futures and vdm (virtual data mover) concepts from this library. Please check miniasync(7) for more details.

The struct pmem2_future is a structure describing a task to be done asynchronously taking into account persistence of the operation. It means that by the time the future is complete, all the data is safely written into a persistent domain.

The pmem2_config_set_vdm sets a vdm structure in the pmem2_config. This structure will be used by pmem2_*_async functions, to create a pmem2_future. If vdm is not set in the config, pmem2_map_new will use a default one which uses a pmem2 memory movement functions to perform memory operations. (pmem2_get_memcpy_fn(3), pmem2_get_memmove_fn(3), pmem2_get_memset_fn(3)).

The pmem2_memcpy_async uses vdm structure held inside the pmem2_map structure to initialise and returns pmem2_future. This future will perform memcpy operation defined in vdm to copy len bytes from src to pmemdest. In the current implementation flags are ignored.

The pmem2_memmove_async returns pmem2_future which will perform memmove operation defined in vdm to copy len bytes from src to pmemdest. In the current implementation flags are ignored.

The pmem2_memset_async returns pmem2_future which will perform memset operation defined in vdm to fill n bytes from pmemstr with value of int c interpreted as unsigned char. In the current implementation flags are ignored.

RETURN VALUE¶

The pmem2_config_set_vdm always return 0.

The pmem2_memcpy_async returns a new instance of pmem2_future performing memcpy operation. You can execute returned structure using methods from the libminiasync() library such as FUTURE_BUSY_POLL(3).

The pmem2_memmove_async returns a new instance of pmem2_future performing memmove operation.

The pmem2_memset_async returns a new instance of pmem2_future performing memset operation.

SEE ALSO¶

memcpy(3), memmove(3), memset(3), pmem2_get_drain_fn(3), pmem2_get_memcpy_fn(3), pmem2_get_memset_fn(3), pmem2_map_new(3), pmem2_get_persist_fn(3), vdm_memcpy(3), miniasync(7), miniasync_future(7), libpmem2(7) and <https://pmem.io>