Re: [PATCH v3 03/11] s390x/mm: Implement arch_remove_memory()
On 01.07.19 14:47, Michal Hocko wrote:
> On Mon 01-07-19 09:45:03, Michal Hocko wrote:
>> On Mon 27-05-19 13:11:44, David Hildenbrand wrote:
>>> Will come in handy when wanting to handle errors after
>>> arch_add_memory().
>>
>> I do not understand this. Why do you add a code for something that is
>> not possible on this HW (based on the comment - is it still valid btw?)
>
> Same as the previous patch (drop it).
No. As the description says, this will be needed to handle errors in
patch 6 cleanly.
And BTW, with paravirtualied devices like virtio-pmem and virtio-mem,
this will also see some other users in the future.
Thanks.
>
>>> Cc: Martin Schwidefsky
>>> Cc: Heiko Carstens
>>> Cc: Andrew Morton
>>> Cc: Michal Hocko
>>> Cc: Mike Rapoport
>>> Cc: David Hildenbrand
>>> Cc: Vasily Gorbik
>>> Cc: Oscar Salvador
>>> Signed-off-by: David Hildenbrand
>>> ---
>>> arch/s390/mm/init.c | 13 +++--
>>> 1 file changed, 7 insertions(+), 6 deletions(-)
>>>
>>> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
>>> index d552e330fbcc..14955e0a9fcf 100644
>>> --- a/arch/s390/mm/init.c
>>> +++ b/arch/s390/mm/init.c
>>> @@ -243,12 +243,13 @@ int arch_add_memory(int nid, u64 start, u64 size,
>>> void arch_remove_memory(int nid, u64 start, u64 size,
>>> struct vmem_altmap *altmap)
>>> {
>>> - /*
>>> -* There is no hardware or firmware interface which could trigger a
>>> -* hot memory remove on s390. So there is nothing that needs to be
>>> -* implemented.
>>> -*/
>>> - BUG();
>>> + unsigned long start_pfn = start >> PAGE_SHIFT;
>>> + unsigned long nr_pages = size >> PAGE_SHIFT;
>>> + struct zone *zone;
>>> +
>>> + zone = page_zone(pfn_to_page(start_pfn));
>>> + __remove_pages(zone, start_pfn, nr_pages, altmap);
>>> + vmem_remove_mapping(start, size);
>>> }
>>> #endif
>>> #endif /* CONFIG_MEMORY_HOTPLUG */
>>> --
>>> 2.20.1
>>>
>>
>> --
>> Michal Hocko
>> SUSE Labs
>
--
Thanks,
David / dhildenb
Re: [PATCH v3 03/11] s390x/mm: Implement arch_remove_memory()
On Mon 01-07-19 09:45:03, Michal Hocko wrote:
> On Mon 27-05-19 13:11:44, David Hildenbrand wrote:
> > Will come in handy when wanting to handle errors after
> > arch_add_memory().
>
> I do not understand this. Why do you add a code for something that is
> not possible on this HW (based on the comment - is it still valid btw?)
Same as the previous patch (drop it).
> > Cc: Martin Schwidefsky
> > Cc: Heiko Carstens
> > Cc: Andrew Morton
> > Cc: Michal Hocko
> > Cc: Mike Rapoport
> > Cc: David Hildenbrand
> > Cc: Vasily Gorbik
> > Cc: Oscar Salvador
> > Signed-off-by: David Hildenbrand
> > ---
> > arch/s390/mm/init.c | 13 +++--
> > 1 file changed, 7 insertions(+), 6 deletions(-)
> >
> > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> > index d552e330fbcc..14955e0a9fcf 100644
> > --- a/arch/s390/mm/init.c
> > +++ b/arch/s390/mm/init.c
> > @@ -243,12 +243,13 @@ int arch_add_memory(int nid, u64 start, u64 size,
> > void arch_remove_memory(int nid, u64 start, u64 size,
> > struct vmem_altmap *altmap)
> > {
> > - /*
> > -* There is no hardware or firmware interface which could trigger a
> > -* hot memory remove on s390. So there is nothing that needs to be
> > -* implemented.
> > -*/
> > - BUG();
> > + unsigned long start_pfn = start >> PAGE_SHIFT;
> > + unsigned long nr_pages = size >> PAGE_SHIFT;
> > + struct zone *zone;
> > +
> > + zone = page_zone(pfn_to_page(start_pfn));
> > + __remove_pages(zone, start_pfn, nr_pages, altmap);
> > + vmem_remove_mapping(start, size);
> > }
> > #endif
> > #endif /* CONFIG_MEMORY_HOTPLUG */
> > --
> > 2.20.1
> >
>
> --
> Michal Hocko
> SUSE Labs
--
Michal Hocko
SUSE Labs
Re: [PATCH v3 03/11] s390x/mm: Implement arch_remove_memory()
On Mon 27-05-19 13:11:44, David Hildenbrand wrote:
> Will come in handy when wanting to handle errors after
> arch_add_memory().
I do not understand this. Why do you add a code for something that is
not possible on this HW (based on the comment - is it still valid btw?)
> Cc: Martin Schwidefsky
> Cc: Heiko Carstens
> Cc: Andrew Morton
> Cc: Michal Hocko
> Cc: Mike Rapoport
> Cc: David Hildenbrand
> Cc: Vasily Gorbik
> Cc: Oscar Salvador
> Signed-off-by: David Hildenbrand
> ---
> arch/s390/mm/init.c | 13 +++--
> 1 file changed, 7 insertions(+), 6 deletions(-)
>
> diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
> index d552e330fbcc..14955e0a9fcf 100644
> --- a/arch/s390/mm/init.c
> +++ b/arch/s390/mm/init.c
> @@ -243,12 +243,13 @@ int arch_add_memory(int nid, u64 start, u64 size,
> void arch_remove_memory(int nid, u64 start, u64 size,
> struct vmem_altmap *altmap)
> {
> - /*
> - * There is no hardware or firmware interface which could trigger a
> - * hot memory remove on s390. So there is nothing that needs to be
> - * implemented.
> - */
> - BUG();
> + unsigned long start_pfn = start >> PAGE_SHIFT;
> + unsigned long nr_pages = size >> PAGE_SHIFT;
> + struct zone *zone;
> +
> + zone = page_zone(pfn_to_page(start_pfn));
> + __remove_pages(zone, start_pfn, nr_pages, altmap);
> + vmem_remove_mapping(start, size);
> }
> #endif
> #endif /* CONFIG_MEMORY_HOTPLUG */
> --
> 2.20.1
>
--
Michal Hocko
SUSE Labs
[PATCH v3 03/11] s390x/mm: Implement arch_remove_memory()
Will come in handy when wanting to handle errors after
arch_add_memory().
Cc: Martin Schwidefsky
Cc: Heiko Carstens
Cc: Andrew Morton
Cc: Michal Hocko
Cc: Mike Rapoport
Cc: David Hildenbrand
Cc: Vasily Gorbik
Cc: Oscar Salvador
Signed-off-by: David Hildenbrand
---
arch/s390/mm/init.c | 13 +++--
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c
index d552e330fbcc..14955e0a9fcf 100644
--- a/arch/s390/mm/init.c
+++ b/arch/s390/mm/init.c
@@ -243,12 +243,13 @@ int arch_add_memory(int nid, u64 start, u64 size,
void arch_remove_memory(int nid, u64 start, u64 size,
struct vmem_altmap *altmap)
{
- /*
-* There is no hardware or firmware interface which could trigger a
-* hot memory remove on s390. So there is nothing that needs to be
-* implemented.
-*/
- BUG();
+ unsigned long start_pfn = start >> PAGE_SHIFT;
+ unsigned long nr_pages = size >> PAGE_SHIFT;
+ struct zone *zone;
+
+ zone = page_zone(pfn_to_page(start_pfn));
+ __remove_pages(zone, start_pfn, nr_pages, altmap);
+ vmem_remove_mapping(start, size);
}
#endif
#endif /* CONFIG_MEMORY_HOTPLUG */
--
2.20.1
