On Thu, Oct 25, 2018 at 02:01:02AM +0300, Igor Stoppa wrote: > > > @@ -1747,6 +1750,10 @@ void *__vmalloc_node_range(unsigned long size, unsigned long align, > > > if (!addr) > > > return NULL; > > > + va = __find_vmap_area((unsigned long)addr); > > > + for (i = 0; i < va->vm->nr_pages; i++) > > > + va->vm->pages[i]->area = va; > > > > I don't like it that you're calling this for _every_ vmalloc() caller > > when most of them will never use this. Perhaps have page->va be initially > > NULL and then cache the lookup in it when it's accessed for the first time. > > > > If __find_vmap_area() was part of the API, this loop could be left out from > __vmalloc_node_range() and the user of the allocation could initialize the > field, if needed. > > What is the reason for keeping __find_vmap_area() private? Well, for one, you're walking the rbtree without holding the spinlock, so you're going to get crashes. I don't see why we shouldn't export find_vmap_area() though. Another way we could approach this is to embed the vmap_area in the vm_struct. It'd require a bit of juggling of the alloc/free paths in vmalloc, but it might be worthwhile.
