Re: [Xen-devel] [PATCH] libvchan: interdomain communications library

[Tim Deegan <tim@xxxxxxx>]

At 14:52 -0400 on 24 Aug (1314197572), Daniel De Graaf wrote:
> Agreed, barriers are needed for a robust implementation. Since this is
> a shared library and not xen or kernel code, the existing barrier()/wmb()
> functions are not available. The only existing implementations in Xen
> appear to expand to asm("":::"memory") which does not actually implement
> a memory barrier (i.e. MFENCE or similar opcodes).

AIUI on x86_64, writes are guaranteed to be seen in order so the only
thing that barrier has to protect against is the compiler reordering the
writes.

Tim.

-- 
Tim Deegan <tim@xxxxxxx>
Principal Software Engineer, Xen Platform Team
Citrix Systems UK Ltd.  (Company #02937203, SL9 0BG)

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