Hi Julien,
> -----Original Message-----
> From: Julien Grall <jul...@xen.org>
> Sent: 2021年8月26日 1:07
> To: Wei Chen <wei.c...@arm.com>; xen-devel@lists.xenproject.org;
> sstabell...@kernel.org
> Cc: Bertrand Marquis <bertrand.marq...@arm.com>; Jan Beulich
> <jbeul...@suse.com>
> Subject: Re: [XEN RFC PATCH 27/40] xen/arm: build CPU NUMA node map while
> creating cpu_logical_map
>
> Hi Wei,
>
> On 11/08/2021 11:24, Wei Chen wrote:
> > Sometimes, CPU logical ID maybe different with physical CPU ID.
> > Xen is using CPU logial ID for runtime usage, so we should use
> > CPU logical ID to create map between NUMA node and CPU.
>
> This commit message gives the impression that you are trying to fix a
> bug. However, what you are explaining is the reason why the code will
> use the logical ID rather than physical ID.
>
> I think the commit message should explain what the patch is doing. You
> can then add an explanation why you are using the CPU logical ID.
> Something like "Note we storing the CPU logical ID because...".
>
>
Ok
> >
> > Signed-off-by: Wei Chen <wei.c...@arm.com>
> > ---
> > xen/arch/arm/smpboot.c | 31 ++++++++++++++++++++++++++++++-
> > 1 file changed, 30 insertions(+), 1 deletion(-)
> >
> > diff --git a/xen/arch/arm/smpboot.c b/xen/arch/arm/smpboot.c
> > index aa78958c07..dd5a45bffc 100644
> > --- a/xen/arch/arm/smpboot.c
> > +++ b/xen/arch/arm/smpboot.c
> > @@ -121,7 +121,12 @@ static void __init dt_smp_init_cpus(void)
> > {
> > [0 ... NR_CPUS - 1] = MPIDR_INVALID
> > };
> > + static nodeid_t node_map[NR_CPUS] __initdata =
> > + {
> > + [0 ... NR_CPUS - 1] = NUMA_NO_NODE
> > + };
> > bool bootcpu_valid = false;
> > + uint32_t nid = 0;
> > int rc;
> >
> > mpidr = boot_cpu_data.mpidr.bits & MPIDR_HWID_MASK;
> > @@ -172,6 +177,26 @@ static void __init dt_smp_init_cpus(void)
> > continue;
> > }
> >
> > +#ifdef CONFIG_DEVICE_TREE_NUMA
> > + /*
> > + * When CONFIG_DEVICE_TREE_NUMA is set, try to fetch numa
> infomation
> > + * from CPU dts node, otherwise the nid is always 0.
> > + */
> > + if ( !dt_property_read_u32(cpu, "numa-node-id", &nid) )
>
> You can avoid the #ifdef by writing:
>
> if ( IS_ENABLED(CONFIG_DEVICE_TREE_NUMA) && ... )
>
> However, I would using CONFIG_NUMA because this code is already DT
> specific. So we can shorten the name a bit.
>
OK
> > + {
> > + printk(XENLOG_WARNING
> > + "cpu[%d] dts path: %s: doesn't have numa infomation!\n",
>
> s/information/information/
OK
>
> > + cpuidx, dt_node_full_name(cpu));
> > + /*
> > + * The the early stage of NUMA initialization, when Xen
> found any
>
> s/The/During/?
Oh, yes, I will fix it.
>
> > + * CPU dts node doesn't have numa-node-id info, the NUMA
> will be
> > + * treated as off, all CPU will be set to a FAKE node 0. So
> if we
> > + * get numa-node-id failed here, we should set nid to 0.
> > + */
> > + nid = 0;
> > + }
> > +#endif
> > +
> > /*
> > * 8 MSBs must be set to 0 in the DT since the reg property
> > * defines the MPIDR[23:0]
> > @@ -231,9 +256,12 @@ static void __init dt_smp_init_cpus(void)
> > {
> > printk("cpu%d init failed (hwid %"PRIregister"): %d\n", i,
> hwid, rc);
> > tmp_map[i] = MPIDR_INVALID;
> > + node_map[i] = NUMA_NO_NODE;
> > }
> > - else
> > + else {
> > tmp_map[i] = hwid;
> > + node_map[i] = nid;
> > + }
> > }
> >
> > if ( !bootcpu_valid )
> > @@ -249,6 +277,7 @@ static void __init dt_smp_init_cpus(void)
> > continue;
> > cpumask_set_cpu(i, &cpu_possible_map);
> > cpu_logical_map(i) = tmp_map[i];
> > + numa_set_node(i, node_map[i]);
> > }
> > }
> > >
>
> Cheers,
>
> --
> Julien Grall
