>>> On 14.10.15 at 12:03, <feng...@intel.com> wrote: > >> -----Original Message----- >> From: Jan Beulich [mailto:jbeul...@suse.com] >> Sent: Wednesday, October 14, 2015 5:46 PM >> To: Wu, Feng <feng...@intel.com> >> Cc: Andrew Cooper <andrew.coop...@citrix.com>; xen-devel@lists.xen.org; >> Keir Fraser <k...@xen.org> >> Subject: RE: [PATCH v8 02/17] Add cmpxchg16b support for x86-64 >> >> >>> On 14.10.15 at 11:29, <feng...@intel.com> wrote: >> > I understand your comments above. My understanding about the gcc >> > online doc is we don't need to add memory clobber when the variable >> > is either an input _or_ output one. However, seems your options is >> > memory clobber can be removed only when it is an input _and_ output >> > one. It would be highly appreciated if you can correct me if I understand >> > the doc incorrectly. >> >> Yes, I'm pretty convinced you read it wrong: "performs memory >> reads or writes to items other than those listed in the input and >> output operands" means _any_ operation not expressed by the >> ams operands. The two sentence following that actually explain >> this in more detail. IOW - unless your operands correctly express >> _everything_ the assembly instruction(s) do(es), you need a >> clobber (and this is not limited to memory). > > Thanks for the clarification. So do you think it is better to send only > this single patch after fixing the issue in your comments, or wait > for the next version of this whole patch set?
I don't know - I didn't get around to look at the rest of the series yet. Jan _______________________________________________ Xen-devel mailing list Xen-devel@lists.xen.org http://lists.xen.org/xen-devel
