Messages in this thread | | | Date | Tue, 14 Nov 2023 19:39:40 +0100 | Subject | Re: [PATCH 6/8] s390/mm: implement MEM_PHYS_ONLINE MEM_PHYS_OFFLINE memory notifiers | From | David Hildenbrand <> |
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On 14.11.23 19:02, Sumanth Korikkar wrote: > Implement MEM_PHYS_ONLINE and MEM_PHYS_OFFLINE memory notifiers on s390 > > Implementation of MEM_PHYS_ONLINE Memory Notifier: > * Transition the memory block to an accessible/online state using the > sclp assign command. > * Execute __add_pages() for the memory block, enabling a self-contained > memory map range. For boot-time memory, vmemmap mapping is carried out > through sparse_init(). > > Implementation of MEM_PHYS_OFFLINE Memory Notifier: > * Execute __remove_pages() exclusively for the memory block (applicable > where a self-contained memory map was possible before). > * Shift the memory block to an inaccessible/offline state using the sclp > unassign command. > > Additional Implementation Considerations: > * When MHP_MEMMAP_ON_MEMORY is disabled, the system retains the old > behavior. This means the memory map is allocated from default memory, > and struct vmemmap pages are populated during the standby memory > detection phase. > * With MHP_MEMMAP_ON_MEMORY enabled (allowing self-contained memory > map), the memory map is allocated using the self-contained memory map > range. Struct vmemmap pages are populated during the memory hotplug > phase. > * If MACHINE_HAS_EDAT1 is unavailable, MHP_MEMMAP_ON_MEMORY is > automatically disabled. This ensures that vmemmap pagetables do not > consume additional memory from the default memory allocator. > * The MEM_GOING_ONLINE notifier has been modified to perform no > operation, as MEM_PHYS_ONLINE already executes the sclp assign > command. > * The MEM_CANCEL_ONLINE notifier now performs no operation, as > MEM_PHYS_OFFLINE already executes the sclp unassign command. > * The call to __add_pages() in arch_add_memory() with altmap support is > skipped. This operation is deferred and will be performed later in the > MEM_PHYS_ONLINE notifier. > > Reviewed-by: Gerald Schaefer <gerald.schaefer@linux.ibm.com> > Signed-off-by: Sumanth Korikkar <sumanthk@linux.ibm.com> > --- > arch/s390/mm/init.c | 16 +++++++++++++++- > drivers/s390/char/sclp_cmd.c | 33 ++++++++++++++++++++++++++++++--- > 2 files changed, 45 insertions(+), 4 deletions(-) > > diff --git a/arch/s390/mm/init.c b/arch/s390/mm/init.c > index 8d9a60ccb777..db505ed590b2 100644 > --- a/arch/s390/mm/init.c > +++ b/arch/s390/mm/init.c > @@ -288,6 +288,12 @@ int arch_add_memory(int nid, u64 start, u64 size, > rc = vmem_add_mapping(start, size); > if (rc) > return rc; > + /* > + * If MHP_MEMMAP_ON_MEMORY is enabled, perform __add_pages() during memory > + * onlining phase > + */ > + if (params->altmap) > + return 0;
So we'd have added memory blocks without a memmap? Sorry, but this seems to further hack into the s390x direction.
Maybe s390x should just provide a dedicate interface to add these memory blocks instead of adding them during boot and then relying on the old way of using online/offline set them online/offline.
-- Cheers,
David / dhildenb
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