On 08/28/2013 09:44 PM, Paolo Bonzini wrote: > Il 26/08/2013 10:43, Andrew Jones ha scritto: >> >> ----- Original Message ----- >>>> On 08/26/2013 03:46 PM, Andrew Jones wrote: >>>>>>>>>> Is this patch still necessary? I thought that dropping the >>>>>>>>>>>>>> numa_num_configured_nodes() calls from patch 8/12 got rid >>>>>>>>>>>>>> of the need for this library. Maybe I missed other uses? >>>>>>>>>> >>>>>>>>>> Yes, in 08/12 we also use mbind(), >>>>>> You don't need a whole library for mbind(), it's a syscall. See >>>>>> syscall(2). >>>>>> >>>>>>>>>> and in 09/12 we use max_numa_node(). >>>>>> Really? I didn't see it there. And anyway, that goes back to our >>>>>> discussion >>>>>> about setting qemu's MAX_NODES to whatever we think qemu should support, >>>>>> and then just checking that we don't blow that limit whenever reading >>>>>> host node info, i.e. >>>>>> >>>>>> maxnode = 0; >>>>>> while (host_nodes[maxnode] && maxnode < MAX_NODES) >>>>>> node_read(&info[maxnode++]); >>>>>> >>>>>> type of a thing. >>>>>> >>>>>> And, if there's a place you really need to know the current online number >>>>>> of host nodes, then, like I said earlier, you should just go to sysfs >>>>>> yourself. libnuma:numa_max_node() returns an int that it only initializes >>>>>> at library load time, so it's not going to adapt to onlining/offlining. >>>> >>>> OK, thank you. >>>> Then I should define MPOL_* macros in QEMU and use mbind(2) syscall >>>> directly, >>>> right? >> Hmm, yeah, that's too bad that numaif.h is part of libnuma, and not a more >> general lib. Whether or not we want to redefine those symbols within >> qemu, in order to avoid the dependency on installing numactl-devel, isn't >> something I can answer. That's a better question for Anthony. Anthony? Paolo, >> any opinions? Maybe we should pick up uapi/linux/mempolicy.h with the >> linux-header synch script? >> > > I think using libnuma is fine. In principle this could be used on other > OSes than Linux, I think?
But seems that mbind(2) is Linux-specific syscall, right? Thanks, Wanlong Gao > > Paolo >
