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
