ck_epoch_barrier (3) - Linux Manuals

ck_epoch_barrier: block until a grace period and all callbacks have been dispatched

NAME

ck_epoch_barrier - block until a grace period and all callbacks have been dispatched

LIBRARY

Concurrency Kit (libck, -lck)

SYNOPSIS

In ck_epoch.h Ft void Fn ck_epoch_barrier ck_epoch_record_t *record

DESCRIPTION

The Fn ck_epoch_barrier 3 function will block the caller until a grace period has been detected, according to the semantics of epoch reclamation. Any objects requiring safe memory reclamation which are logically deleted are safe for physical deletion following a call to Fn ck_epoch_barrier 3 . This function will also dispatch all callbacks associated with Fa epoch that were previously scheduled via Fn ck_epoch_call 3 .

EXAMPLE

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

/*
 * epoch was previously initialized with ck_epoch_init.
 * stack was previously initialized with ck_stack_init.
 */
ck_epoch_t *epoch;
ck_stack_t *stack;

void
function(void)
{
        ck_epoch_record_t *record;
        ck_stack_entry_t *s;

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

        /*
         * We are using an epoch section here to guarantee no
         * nodes in the stack are deleted while we are dereferencing
         * them. This is needed here because there are multiple writers.
         * If there was only one thread popping from the this stack,
         * then there is no need to ck_epoch_begin/ck_epoch_end.
         */
        ck_epoch_begin(record);

        /* Logically delete an object. */
        s = ck_stack_pop_upmc(stack);

        ck_epoch_end(record);

        /*
         * Wait until no threads could possibly have a reference to the
         * object we just popped (assume all threads are simply executing
         * ck_stack_pop_upmc).
         */
        ck_epoch_barrier(record);

        /* It is now safe to physically delete the object. */
        free(s);
        return;
}

RETURN VALUES

This function has no return value.

ERRORS

Behavior is undefined if the object pointed to by Fa epoch is not a valid epoch object. The object pointed to by Fa record must have been previously registered via Fn ck_epoch_register 3 .