On Wed, Sep 06, 2023 at 11:13:27AM +0800, Kefeng Wang wrote: > On 2023/9/6 10:47, Matthew Wilcox wrote: > > On Tue, Sep 05, 2023 at 06:35:08PM +0800, Kefeng Wang wrote: > > > It is needed 4095 pages(1G) or 7 pages(2M) to be allocated once in > > > alloc_vmemmap_page_list(), so let's add a bulk allocator varietas > > > alloc_pages_bulk_list_node() and switch alloc_vmemmap_page_list() > > > to use it to accelerate page allocation. > > > > Argh, no, please don't do this. > > > > Iterating a linked list is _expensive_. It is about 10x quicker to > > iterate an array than a linked list. Adding the list_head option > > to __alloc_pages_bulk() was a colossal mistake. Don't perpetuate it. > > > > These pages are going into an array anyway. Don't put them on a list > > first. > > struct vmemmap_remap_walk - walk vmemmap page table > > * @vmemmap_pages: the list head of the vmemmap pages that can be freed > * or is mapped from. > > At present, the struct vmemmap_remap_walk use a list for vmemmap page table > walk, so do you mean we need change vmemmap_pages from a list to a array > firstly and then use array bulk api, even kill list bulk api ? That would be better, yes.
