tools/memory-model/litmus-tests/IRIW+fencembonceonces+OnceOnce.litmus

Source file repositories/reference/linux-study-clean/tools/memory-model/litmus-tests/IRIW+fencembonceonces+OnceOnce.litmus

File Facts

System
Linux kernel
Corpus path
tools/memory-model/litmus-tests/IRIW+fencembonceonces+OnceOnce.litmus
Extension
.litmus
Size
731 bytes
Lines
46
Domain
Support Tooling And Documentation
Bucket
tools
Inferred role
Support Tooling And Documentation: tools
Status
atlas-only

Why This File Exists

Repository support layer: documentation, build tooling, samples, user-space helper tools, generated initramfs support, licenses, and validation utilities.

Dependency Surface

Detected Declarations

Annotated Snippet

C IRIW+fencembonceonces+OnceOnce

(*
 * Result: Never
 *
 * Test of independent reads from independent writes with smp_mb()
 * between each pairs of reads.  In other words, is smp_mb() sufficient to
 * cause two different reading processes to agree on the order of a pair
 * of writes, where each write is to a different variable by a different
 * process?  This litmus test exercises LKMM's "propagation" rule.
 *)

{}

P0(int *x)
{
	WRITE_ONCE(*x, 1);
}

P1(int *x, int *y)
{
	int r0;
	int r1;

	r0 = READ_ONCE(*x);
	smp_mb();
	r1 = READ_ONCE(*y);
}

P2(int *y)
{
	WRITE_ONCE(*y, 1);
}

P3(int *x, int *y)
{
	int r0;
	int r1;

	r0 = READ_ONCE(*y);
	smp_mb();
	r1 = READ_ONCE(*x);
}

exists (1:r0=1 /\ 1:r1=0 /\ 3:r0=1 /\ 3:r1=0)

Annotation

Implementation Notes