On Sun, Feb 11, 2018 at 05:19:17AM +0200, Igor Stoppa wrote: > The struct page has a "mapping" field, which can be re-used, to store a > pointer to the parent area. This will avoid more expensive searches. > > As example, the function find_vm_area is reimplemented, to take advantage > of the newly introduced field.
Umm. Is it more efficient? You're replacing an rb-tree search with a page-table walk. You eliminate a spinlock, which is great, but is the page-table walk more efficient? I suppose it'll depend on the depth of the rb-tree, and (at least on x86), the page tables should already be in cache. Unrelated to this patch, I'm working on a patch to give us page_type, and I think I'll allocate a bit to mark pages which are vmalloced.
