Re: [PATCH v4 24/26] arch_numa: switch over to numa_memblks

Mike Rapoport
2024-08-07T18:20:48Z

On Wed, Aug 07, 2024 at 08:58:37AM +0200, Arnd Bergmann wrote:
> On Wed, Aug 7, 2024, at 08:41, Mike Rapoport wrote:
> > From: "Mike Rapoport (Microsoft)" <rppt@kernel.org>
> >
> > Until now arch_numa was directly translating firmware NUMA information
> > to memblock.
>
> I get a link time warning from this:
>
> WARNING: modpost: vmlinux: section mismatch in reference: numa_set_cpumask+0x24 (section: .text.unlikely) -> early_cpu_to_node (section: .init.text)

I didn't see this neither in my build tests nor in kbuild reports :/

> > @@ -142,7 +144,7 @@ void __init early_map_cpu_to_node(unsigned int cpu, int nid)
> > unsigned long __per_cpu_offset[NR_CPUS] __read_mostly;
> > EXPORT_SYMBOL(__per_cpu_offset);
> >
> > -int __init early_cpu_to_node(int cpu)
> > +int early_cpu_to_node(int cpu)
> > {
> > return cpu_to_node_map[cpu];
> > }
>
> early_cpu_to_node() can no longer be __init here
>
> > +#endif /* CONFIG_NUMA_EMU */
> > diff --git a/include/asm-generic/numa.h b/include/asm-generic/numa.h
> > index c32e0cf23c90..c2b046d1fd82 100644
> > --- a/include/asm-generic/numa.h
> > +++ b/include/asm-generic/numa.h
> > @@ -32,8 +32,6 @@ static inline const struct cpumask *cpumask_of_node(int node)
> >
> > void __init arch_numa_init(void);
> > int __init numa_add_memblk(int nodeid, u64 start, u64 end);
> > -void __init numa_set_distance(int from, int to, int distance);
> > -void __init numa_free_distance(void);
> > void __init early_map_cpu_to_node(unsigned int cpu, int nid);
> > int __init early_cpu_to_node(int cpu);
> > void numa_store_cpu_info(unsigned int cpu);
>
> but is still declared as __init in the header, so it is
> still put in that section and discarded after boot.

I believe this should fix it

diff --git a/include/asm-generic/numa.h b/include/asm-generic/numa.h
index c2b046d1fd82..e063d6487f66 100644
--- a/include/asm-generic/numa.h
+++ b/include/asm-generic/numa.h
@@ -33,7 +33,7 @@ static inline const struct cpumask *cpumask_of_node(int node)
void __init arch_numa_init(void);
int __init numa_add_memblk(int nodeid, u64 start, u64 end);
void __init early_map_cpu_to_node(unsigned int cpu, int nid);
-int __init early_cpu_to_node(int cpu);
+int early_cpu_to_node(int cpu);
void numa_store_cpu_info(unsigned int cpu);
void numa_add_cpu(unsigned int cpu);
void numa_remove_cpu(unsigned int cpu);

> I was confused by this at first, since the 'early' name
> seems to imply that you shouldn't call it once the system
> is up, but now you do.

I agree that this is confusing, but that's what x86 does and numa_emulation
uses.

> Arnd
>

--
Sincerely yours,
Mike.