On 01.07.19 14:47, Michal Hocko wrote:

On Mon 01-07-19 09:45:03, Michal Hocko wrote:

quoted

On Mon 27-05-19 13:11:44, David Hildenbrand wrote:

quoted

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.

quoted

quoted

Cc: Martin Schwidefsky <redacted>
Cc: Heiko Carstens <redacted>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Rapoport <redacted>
Cc: David Hildenbrand <redacted>
Cc: Vasily Gorbik <gor@linux.ibm.com>
Cc: Oscar Salvador <redacted>
Signed-off-by: David Hildenbrand <redacted>
---
 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