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30 lines
545 B
30 lines
545 B
C MP+fencewmbonceonce+fencermbonceonce |
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(* |
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* Result: Never |
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* |
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* This litmus test demonstrates that smp_wmb() and smp_rmb() provide |
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* sufficient ordering for the message-passing pattern. However, it |
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* is usually better to use smp_store_release() and smp_load_acquire(). |
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*) |
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{} |
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P0(int *buf, int *flag) // Producer |
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{ |
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WRITE_ONCE(*buf, 1); |
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smp_wmb(); |
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WRITE_ONCE(*flag, 1); |
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} |
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P1(int *buf, int *flag) // Consumer |
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{ |
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int r0; |
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int r1; |
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r0 = READ_ONCE(*flag); |
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smp_rmb(); |
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r1 = READ_ONCE(*buf); |
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} |
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exists (1:r0=1 /\ 1:r1=0) (* Bad outcome. *)
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