pmem2 API version 1.0

The PMDK repository on GitHub is the ultimate source of information on PMDK from release 2.0! For all questions and to submit eventual issues please follow to that repository. The PMDK documentation collected here should be valid up to the 1.13.1 release but is maintained only on a best-effort basis and may not reflect the latest state of the art.

comment: <> (SPDX-License-Identifier: BSD-3-Clause comment: <> (Copyright 2020, Intel Corporation)

NAME
SYNOPSIS
DESCRIPTION
RETURN VALUE
SEE ALSO

NAME

pmem2_get_flush_fn() - get a flush function

SYNOPSIS

#include <libpmem2.h>

typedef void (*pmem2_flush_fn)(const void *ptr, size_t size);

struct pmem2_map;

pmem2_flush_fn pmem2_get_flush_fn(struct pmem2_map *map);

DESCRIPTION

The pmem2_get_flush_fn() function returns a pointer to a function responsible for efficiently flushing data in the range owned by the map.

Flushing data using pmem2_flush_fn does not guarantee that the data is stored durably by the time it returns. To get this guarantee, application should either use the persist operation (see pmem2_get_persist_fn(3)) or follow pmem2_flush_fn by a drain operation (see pmem2_get_drain_fn(3)).

There are no alignment restrictions on the range described by ptr and size, but pmem2_flush_fn may expand the range as necessary to meet platform alignment requirements.

There is nothing atomic or transactional about pmem2_flush_fn. Any unwritten stores in the given range will be written, but some stores may have already been written by virtue of normal cache eviction/replacement policies. Correctly written code must not depend on stores waiting until pmem2_flush_fn is called to be flushed – they can be flushed at any time before pmem2_flush_fn is called.

If two (or more) mappings share the same pmem2_flush_fn and they are adjacent to each other, it is safe to call this function for a range spanning those mappings.

RETURN VALUE

The pmem2_get_flush_fn() function never returns NULL.

The pmem2_get_flush_fn() for the same map always returns the same function. This means that it’s safe to cache its return value. However, this function is very cheap (because it returns a precomputed value), so caching may not be necessary.

SEE ALSO

pmem2_get_drain_fn(3), pmem2_get_persist_fn(3), pmem2_map_new(3), libpmem2(7) and https://pmem.io

The contents of this web site and the associated GitHub repositories are BSD-licensed open source.