Documentation/litmus-tests/atomic/cmpxchg-fail-ordered-2.litmus

File Facts

System

Linux kernel

Corpus path

Documentation/litmus-tests/atomic/cmpxchg-fail-ordered-2.litmus

Extension

.litmus

Size

392 bytes

Lines

31

Domain

Support Tooling And Documentation

Bucket

Documentation

Inferred role

Support Tooling And Documentation: Documentation

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.

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

Dependency Surface

• No C-style include directives detected by the generator.

Detected Declarations

• function smp_mb__after_atomic

Annotated Snippet

C cmpxchg-fail-ordered-2

(*
 * Result: Never
 *
 * Demonstrate use of smp_mb__after_atomic() to make a failing cmpxchg
 * operation have acquire ordering.
 *)

{}

P0(int *x, int *y)
{
	int r1;

	WRITE_ONCE(*x, 1);
	r1 = cmpxchg(y, 0, 1);
}

P1(int *x, int *y)
{
	int r1;
	int r2;

	r1 = cmpxchg(y, 0, 1);
	smp_mb__after_atomic();
	r2 = READ_ONCE(*x);
}

exists (0:r1=0 /\ 1:r1=1 /\ 1:r2=0)

Annotation

• Detected declarations: `function smp_mb__after_atomic`.
• Atlas domain: Support Tooling And Documentation / Documentation.
• Implementation status: atlas-only.

Implementation Notes

• This generated page is the file-by-file coverage layer; curated subsystem chapters should link here when they synthesize a multi-file control flow.
• Core OS pages should be promoted from atlas-only to deep-reviewed when they explain data structures, invariants, locking, lifecycle, and C implementation snippets.
• Driver-family pages are intentionally pattern-oriented unless they are part of the selected PCIe/NVMe representative device path.