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Re: [Xen-devel] [PATCH] fix event channel notification loss on IA64
On 29 Jun 2006, at 06:43, Isaku Yamahata wrote:
evtchn_do_upcall() has a micro optimization which is depends on that xchg is a barrier. However xchg of IA64 has acquire semantics so that event channel notification is lost sometimes. This patch fixes it.
clear_bit() isn't a barrier either (at least according to Linux bitop semantics). You want 'rmb();'. I suggest just putting it inside ifndef CONFIG_X86, with the comment about XCHG being a barrier on x86 placed just before the ifndef. Leave the zap of pending flag as a plain write.
-- Keir _______________________________________________ Xen-devel mailing list Xen-devel@xxxxxxxxxxxxxxxxxxx http://lists.xensource.com/xen-devel
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