Messages in this thread | | | Subject | Re: [RFC] Tagging of vmalloc pages for supporting the pmalloc allocator | From | Igor Stoppa <> | Date | Fri, 4 Aug 2017 11:02:46 +0300 |
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On 03/08/17 18:15, Michal Hocko wrote:
> I would check the one where we have mapping. It is rather unlikely > vmalloc users would touch this one.
That was also the initial recommendation from Jerome Glisse, but it seemed unusable, because of the related comment.
I should have asked for clarifications back then :-(
But it's never too late ...
struct page { /* First double word block */ unsigned long flags; /* Atomic flags, some possibly * updated asynchronously */ union { struct address_space *mapping; /* If low bit clear, points to * inode address_space, or NULL. * If page mapped as anonymous * memory, low bit is set, and * it points to anon_vma object: * see PAGE_MAPPING_ANON below. */ ... }
mapping seems to be used exclusively in 2 ways, based on the value of its lower bit.
Therefore I discarded it as valid option ("private", otoh was far more alluring), but maybe I could wrap it inside a union, together with vm_area?
--- thanks, igor
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