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? Paolo
