On 10/14/2015 02:49 PM, Michael Ellerman wrote: > On Wed, 2015-10-14 at 14:32 +0530, Anshuman Khandual wrote: >> On shared processor LPARs, H_HOME_NODE_ASSOCIATIVITY hcall provides the >> dynamic virtual-physical mapping for any given processor. Currently we >> use VPHN node ID information only after getting either a PRRN or a VPHN >> event. But during boot time inside the function numa_setup_cpu, we still >> query the OF device tree for the node ID value which might be different >> than what can be fetched from the H_HOME_NODE_ASSOCIATIVITY hcall. In a >> scenario where there are no PRRN or VPHN event after boot, all node-cpu >> mapping will remain incorrect there after. >> >> With this proposed change, numa_setup_cpu will try to override the OF >> device tree fetched node ID information with H_HOME_NODE_ASSOCIATIVITY >> hcall fetched node ID value. Right now shared processor property of the >> LPAR cannot be queried as VPA inializaion happens after numa_setup_cpu >> during boot time. So initmem_init function has been moved after ppc_md. >> setup_arch inside setup_arch during boot. > > I would be *very* reluctant to change the order of initmem_init() vs > setup_arch(). > > At a minimum you'd need to go through every setup_arch() implementation and > carefully determine if the ordering of what it does matters vs initmem_init(). > And then you'd need to test on every affected platform. > > So I suggest you think of a different way to do it if at all possible.
vpa_init() is being called inside pSeries_setup_arch which is ppc_md .setup_arch for the platform. Its called directly for the boot cpu and through smp_init_pseries_xics for other cpus on the system. Not sure what is the reason behind calling vpa_init() from XICS init though. If we can move all these vpa_init() calls from pSeries_setup_arch to initmem_init just before calling numa_setup_cpu, the VPA area would be initialized when we need it during boot. Will look in this direction. _______________________________________________ Linuxppc-dev mailing list Linuxppc-dev@lists.ozlabs.org https://lists.ozlabs.org/listinfo/linuxppc-dev
