On Fri, Jun 10, 2022 at 01:37:20PM +0800, Baolu Lu wrote:
On 2022/6/9 20:49, Jason Gunthorpe wrote:
+void iommu_free_pgtbl_pages(struct iommu_domain *domain,It seems OK, but I wonder if there is benifit to using
+ struct list_head *pages)
+{
+ struct page *page, *next;
+
+ if (!domain->concurrent_traversal) {
+ put_pages_list(pages);
+ return;
+ }
+
+ list_for_each_entry_safe(page, next, pages, lru) {
+ list_del(&page->lru);
+ call_rcu(&page->rcu_head, pgtble_page_free_rcu);
+ }
put_pages_list() from the rcu callback
The price is that we need to allocate a "struct list_head" and free it
in the rcu callback as well. Currently the list_head is sitting in the
stack.
You'd have to use a different struct page layout so that the list_head
was in the struct page and didn't overlap with the rcu_head