Re: [PATCH v6 4/4] mm/hwpoison: introduce per-memory_block hwpoison counter

[HORIGUCHI NAOYA(堀口 直也)]

On Sat, Oct 15, 2022 at 10:28:00AM +0800, Miaohe Lin wrote:
> On 2022/10/7 9:07, Naoya Horiguchi wrote:
...
> > diff --git a/include/linux/memory.h b/include/linux/memory.h
> > index aa619464a1df..ad8cd9bb3239 100644
> > --- a/include/linux/memory.h
> > +++ b/include/linux/memory.h
> > @@ -85,6 +85,9 @@ struct memory_block {
> >  	unsigned long nr_vmemmap_pages;
> >  	struct memory_group *group;	/* group (if any) for this block */
> >  	struct list_head group_next;	/* next block inside memory group */
> > +#if defined(CONFIG_MEMORY_FAILURE) && defined(CONFIG_MEMORY_HOTPLUG)
> > +	atomic_long_t nr_hwpoison;
> > +#endif
> >  };
> >  
> >  int arch_get_memory_phys_device(unsigned long start_pfn);
> > diff --git a/include/linux/mm.h b/include/linux/mm.h
> > index 17119dbf8fad..f80269e90772 100644
> > --- a/include/linux/mm.h
> > +++ b/include/linux/mm.h
> > @@ -3280,6 +3280,7 @@ extern int soft_offline_page(unsigned long pfn, int flags);
> >  extern int __get_huge_page_for_hwpoison(unsigned long pfn, int flags,
> >  					bool *migratable_cleared);
> >  extern void num_poisoned_pages_inc(unsigned long pfn);
> > +extern void num_poisoned_pages_sub(unsigned long pfn, long i);
> 
> The prototype of this function is: *inline* void num_poisoned_pages_sub(unsigned long pfn, long i).
> The combination of inline and extern looks weird to me. Is this a common use case?

No, it seems not.  I can find a few place of such a comination like task_curr()
and raise_softirq_irqoff(), but as long as I understand, there's little meaning
(showing explicitly but redundant) to add extern keyword to functions in shared
header files. So I think of dropping the extern keyword.

> 
> Anyway, this patch looks good to me. Thanks.
> Reviewed-by: Miaohe Lin <linmiaohe@xxxxxxxxxx>

Thank you.

- Naoya Horiguchi