[v3,03/11] s390x/mm: Implement arch_remove_memory()
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Message ID 20190527111152.16324-4-david@redhat.com
State New
Headers show
Series
  • [v3,01/11] mm/memory_hotplug: Simplify and fix check_hotplug_memory_range()
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Commit Message

David Hildenbrand May 27, 2019, 11:11 a.m. UTC
Will come in handy when wanting to handle errors after
arch_add_memory().

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Oscar Salvador <osalvador@suse.com>
Signed-off-by: David Hildenbrand <david@redhat.com>
---
 arch/s390/mm/init.c | 13 +++++++------
 1 file changed, 7 insertions(+), 6 deletions(-)

Comments

Michal Hocko July 1, 2019, 7:45 a.m. UTC | #1
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 <schwidefsky@de.ibm.com>
> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: Michal Hocko <mhocko@suse.com>
> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> Cc: David Hildenbrand <david@redhat.com>
> Cc: Vasily Gorbik <gor@linux.ibm.com>
> Cc: Oscar Salvador <osalvador@suse.com>
> Signed-off-by: David Hildenbrand <david@redhat.com>
> ---
>  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 July 1, 2019, 12:47 p.m. UTC | #2
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 <schwidefsky@de.ibm.com>
> > Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
> > Cc: Andrew Morton <akpm@linux-foundation.org>
> > Cc: Michal Hocko <mhocko@suse.com>
> > Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
> > Cc: David Hildenbrand <david@redhat.com>
> > Cc: Vasily Gorbik <gor@linux.ibm.com>
> > Cc: Oscar Salvador <osalvador@suse.com>
> > Signed-off-by: David Hildenbrand <david@redhat.com>
> > ---
> >  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
David Hildenbrand July 15, 2019, 10:45 a.m. UTC | #3
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 <schwidefsky@de.ibm.com>
>>> Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
>>> Cc: Andrew Morton <akpm@linux-foundation.org>
>>> Cc: Michal Hocko <mhocko@suse.com>
>>> Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
>>> Cc: David Hildenbrand <david@redhat.com>
>>> Cc: Vasily Gorbik <gor@linux.ibm.com>
>>> Cc: Oscar Salvador <osalvador@suse.com>
>>> Signed-off-by: David Hildenbrand <david@redhat.com>
>>> ---
>>>  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
diff mbox series

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 */