Messages in this thread |  | | Date | Fri, 13 Apr 2018 10:11:20 -0700 | From | Matthew Wilcox <> | Subject | Re: [PATCH RFC 2/8] mm: introduce PG_offline |
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On Fri, Apr 13, 2018 at 03:16:26PM +0200, David Hildenbrand wrote: > online_pages()/offline_pages() theoretically allows us to work on > sub-section sizes. This is especially relevant in the context of > virtualization. It e.g. allows us to add/remove memory to Linux in a VM in > 4MB chunks. > > While the whole section is marked as online/offline, we have to know > the state of each page. E.g. to not read memory that is not online > during kexec() or to properly mark a section as offline as soon as all > contained pages are offline.
Can you not use PG_reserved for this purpose?
> + * PG_offline indicates that a page is offline and the backing storage > + * might already have been removed (virtualization). Don't touch!
* PG_reserved is set for special pages, which can never be swapped out. Some * of them might not even exist...
They seem pretty congruent to me.
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