NAME
__insn_barrier —
compiler reorder barrier
SYNOPSIS
#include
<sys/cdefs.h>
void
__insn_barrier();
DESCRIPTION
The__insn_barrier()
macro prevents GCC from moving code across the barrier. In other words, the
compiler is not allowed to reorder read and write commands below the barrier
with the code preceding the barrier. Like with the
volatile
type qualifier, __insn_barrier() may be necessary in
some corner cases to prevent the compiler from misoptimizing.
SEE ALSO
gcc(1), cdefs(3), membar_ops(3)
Paul E. McKenney, Memory Barriers: a Hardware View for Software Hackers, http://www.rdrop.com/users/paulmck/scalability/paper/whymb.2010.06.07c.pdf, June 7, 2010.
HISTORY
The __insn_barrier() macro first appeared
in NetBSD 2.0.