Re: [PATCH v2 3/8] mm/memory_hotplug: arch_remove_memory() and __remove_pages() with CONFIG_MEMORY_HOTPLUG

From: David Hildenbrand <david@redhat.com>
To: Dan Williams <dan.j.williams@intel.com>,
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	Oscar Salvador <osalvador@suse.com>
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Subject: Re: [PATCH v2 3/8] mm/memory_hotplug: arch_remove_memory() and __remove_pages() with CONFIG_MEMORY_HOTPLUG
Date: Mon, 13 May 2019 09:48:31 +0200	[thread overview]
Message-ID: <c027a782-1cef-a076-92a3-3ce36140f3f2@redhat.com> (raw)
In-Reply-To: <CAPcyv4jpnKjeP3QEvF3_9CzdZhtFXN2nMU7P-Ee7y06J3bGZ0A@mail.gmail.com>

On 07.05.19 23:02, Dan Williams wrote:
> On Tue, May 7, 2019 at 11:38 AM David Hildenbrand <david@redhat.com> wrote:
>>
>> Let's prepare for better error handling while adding memory by allowing
>> to use arch_remove_memory() and __remove_pages() even if
>> CONFIG_MEMORY_HOTREMOVE is not set. CONFIG_MEMORY_HOTREMOVE effectively
>> covers
>> - Offlining of system ram (memory block devices) - offline_pages()
>> - Unplug of system ram - remove_memory()
>> - Unplug/remap of device memory - devm_memremap()
>>
>> This allows e.g. for handling like
>>
>> arch_add_memory()
>> rc = do_something();
>> if (rc) {
>>         arch_remove_memory();
>> }
>>
>> Whereby do_something() will for example be memory block device creation
>> after it has been factored out.
> 
> What's left after this? Can we just get rid of CONFIG_MEMORY_HOTREMOVE
> option completely when CONFIG_MEMORY_HOTPLUG is enabled? It's not
> clear to me why there was ever the option to compile out the remove
> code when the add code is included.
> 

If there are no other comments, I will go ahead and rip out
CONFIG_MEMORY_HOTREMOVE completely, gluing the functionality to
CONFIG_MEMORY_HOTPLUG.

-- 

Thanks,

David / dhildenb