Re: [PATCH v3 tip/core/locking 0/3] Memory-barrier documentationupdates

From: Josh Triplett
Date: Fri Nov 22 2013 - 23:00:30 EST


On Fri, Nov 22, 2013 at 11:26:57AM -0800, Paul E. McKenney wrote:
> Hello!
>
> This series applies some long-needed updates to memory-barriers.txt:
>
> 1. Add ACCESS_ONCE() calls where needed to ensure their inclusion
> in code copy-and-pasted from this file.
>
> 2. Add long atomic examples alongside the existing atomics.
>
> 3. Prohibit architectures supporting the Linux kernel from
> speculating stores.
>
> Changes from v2:
>
> o Update examples so that that load against which the subsequent
> store is to be ordered is part of the "if" condition.
>
> o Add an example showing how the compiler can remove "if"
> conditions and how to prevent it from doing so.
>
> o Add ACCESS_ONCE() to the compiler-barrier section.
>
> o Add a sentence noting that transitivity requires smp_mb().
>
> Changes from v1:
>
> o Combined with Peter Zijlstra's speculative-store-prohibition patch.
>
> o Added more pitfalls to avoid when prohibiting speculative
> stores, along with how to avoid them.
>
> o Applied Josh Triplett's review comments.

For v3, all three patches:
Reviewed-by: Josh Triplett <josh@xxxxxxxxxxxxxxxx>
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
Please read the FAQ at http://www.tux.org/lkml/