> On Sep 6, 2023, at 11:13, Kefeng Wang <wangkefeng.wang@xxxxxxxxxx> 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 ? It'll be a little complex for hugetlb_vmemmap. Should it be reasonable to directly use __alloc_pages_bulk in hugetlb_vmemmap itself?
