forked from luck/tmp_suning_uos_patched
8f32543b61
This commit adds comments to the litmus tests summarizing what these tests are intended to demonstrate. [ paulmck: Apply Andrea's and Alan's feedback. ] Suggested-by: Ingo Molnar <mingo@kernel.org> Signed-off-by: Paul E. McKenney <paulmck@linux.vnet.ibm.com> Acked-by: Peter Zijlstra <peterz@infradead.org> Cc: Linus Torvalds <torvalds@linux-foundation.org> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: akiyks@gmail.com Cc: boqun.feng@gmail.com Cc: dhowells@redhat.com Cc: j.alglave@ucl.ac.uk Cc: linux-arch@vger.kernel.org Cc: luc.maranget@inria.fr Cc: nborisov@suse.com Cc: npiggin@gmail.com Cc: parri.andrea@gmail.com Cc: stern@rowland.harvard.edu Cc: will.deacon@arm.com Link: http://lkml.kernel.org/r/1519169112-20593-4-git-send-email-paulmck@linux.vnet.ibm.com Signed-off-by: Ingo Molnar <mingo@kernel.org>
33 lines
494 B
Plaintext
33 lines
494 B
Plaintext
C SB+mbonceonces
|
|
|
|
(*
|
|
* Result: Never
|
|
*
|
|
* This litmus test demonstrates that full memory barriers suffice to
|
|
* order the store-buffering pattern, where each process writes to the
|
|
* variable that the preceding process reads. (Locking and RCU can also
|
|
* suffice, but not much else.)
|
|
*)
|
|
|
|
{}
|
|
|
|
P0(int *x, int *y)
|
|
{
|
|
int r0;
|
|
|
|
WRITE_ONCE(*x, 1);
|
|
smp_mb();
|
|
r0 = READ_ONCE(*y);
|
|
}
|
|
|
|
P1(int *x, int *y)
|
|
{
|
|
int r0;
|
|
|
|
WRITE_ONCE(*y, 1);
|
|
smp_mb();
|
|
r0 = READ_ONCE(*x);
|
|
}
|
|
|
|
exists (0:r0=0 /\ 1:r0=0)
|