NAME

ck_epoch_call — defer function execution until a grace period

LIBRARY

Concurrency Kit (libck, -lck)

SYNOPSIS

#include <ck_epoch.h> typedef struct ck_epoch_entry ck_epoch_entry_t;
typedef void ck_epoch_cb_t(ck_epoch_entry_t *);
void
ck_epoch_call(ck_epoch_record_t *record, ck_epoch_entry_t *entry, ck_epoch_cb_t *function);

DESCRIPTION

The ck_epoch_call(3) function will defer the execution of the function pointed to by function until a grace-period has been detected in epoch. The function will be provided the pointer specified by entry. The function will execute at some time in the future via calls to ck_epoch_reclaim(3), ck_epoch_barrier(3) or ck_epoch_poll(3).

EXAMPLE

#include <ck_epoch.h>
#include <ck_stack.h>
#include <stdlib.h>

/*
 * epoch was previously initialized with ck_epoch_init.
 */
ck_epoch_t *epoch;

struct object {
	int value;
	ck_epoch_entry_t epoch_entry;
};
static struct object *global;

CK_EPOCH_CONTAINER(struct object, epoch_entry, object_container)

void
destroy_object(ck_epoch_entry_t *e)
{
	struct object *o = object_container(e);

	free(o);
	return;
}

void
function(void)
{
	ck_epoch_record_t *record;
	struct object *n;

	record = malloc(sizeof *record);
	ck_epoch_register(&epoch, record, NULL);

	n = malloc(sizeof *n);
	if (n == NULL)
		return;

	n->value = 1;

	/*
	 * We are using an epoch section here because there are multiple
	 * writers. It is also an option to use other forms of blocking
	 * write-side synchronization such as mutexes.
	 */
	ck_epoch_begin(record);
	n = ck_pr_fas_ptr(&global, n);
	ck_epoch_end(record);

	/* Defer destruction of previous object. */
	ck_epoch_call(record, &n->epoch_entry, destroy_object);

	/* Poll epoch sub-system in non-blocking manner. */
	ck_epoch_poll(record);
	return;
}

RETURN VALUES

This function has no return value.

ERRORS

The object pointed to by record must have been previously registered via ck_epoch_register(3).