hugetlb: add a list for tracking in-use HugeTLB pages

hugepage_activelist will be used to track currently used HugeTLB pages.
We need to find the in-use HugeTLB pages to support HugeTLB cgroup removal.
On cgroup removal we update the page's HugeTLB cgroup to point to parent
cgroup.

Signed-off-by: Aneesh Kumar K.V <aneesh.kumar@linux.vnet.ibm.com>
Reviewed-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: David Rientjes <rientjes@google.com>
Cc: Hillf Danton <dhillf@gmail.com>
Reviewed-by: Michal Hocko <mhocko@suse.cz>
Cc: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 7 insertions, 5 deletions

diff --git a/mm/hugetlb.c b/mm/hugetlb.c
index e54b695336f9..b5b6e156ca76 100644
--- a/mm/hugetlb.c
+++ b/mm/hugetlb.c
@@ -510,7 +510,7 @@ void copy_huge_page(struct page *dst, struct page *src)
 static void enqueue_huge_page(struct hstate *h, struct page *page)
 {
         int nid = page_to_nid(page);
-        list_add(&page->lru, &h->hugepage_freelists[nid]);
+        list_move(&page->lru, &h->hugepage_freelists[nid]);
         h->free_huge_pages++;
         h->free_huge_pages_node[nid]++;
 }
@@ -522,7 +522,7 @@ static struct page *dequeue_huge_page_node(struct hstate *h, int nid)
         if (list_empty(&h->hugepage_freelists[nid]))
                 return NULL;
         page = list_entry(h->hugepage_freelists[nid].next, struct page, lru);
-        list_del(&page->lru);
+        list_move(&page->lru, &h->hugepage_activelist);
         set_page_refcounted(page);
         h->free_huge_pages--;
         h->free_huge_pages_node[nid]--;
@@ -626,10 +626,11 @@ static void free_huge_page(struct page *page)
         page->mapping = NULL;
         BUG_ON(page_count(page));
         BUG_ON(page_mapcount(page));
-        INIT_LIST_HEAD(&page->lru);
 
         spin_lock(&hugetlb_lock);
         if (h->surplus_huge_pages_node[nid] && huge_page_order(h) < MAX_ORDER) {
+                /* remove the page from active list */
+                list_del(&page->lru);
                 update_and_free_page(h, page);
                 h->surplus_huge_pages--;
                 h->surplus_huge_pages_node[nid]--;
@@ -642,6 +643,7 @@ static void free_huge_page(struct page *page)
 
 static void prep_new_huge_page(struct hstate *h, struct page *page, int nid)
 {
+        INIT_LIST_HEAD(&page->lru);
         set_compound_page_dtor(page, free_huge_page);
         spin_lock(&hugetlb_lock);
         h->nr_huge_pages++;
@@ -890,6 +892,7 @@ static struct page *alloc_buddy_huge_page(struct hstate *h, int nid)
 
         spin_lock(&hugetlb_lock);
         if (page) {
+                INIT_LIST_HEAD(&page->lru);
                 r_nid = page_to_nid(page);
                 set_compound_page_dtor(page, free_huge_page);
                 /*
@@ -994,7 +997,6 @@ retry:
         list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
                 if ((--needed) < 0)
                         break;
-                list_del(&page->lru);
                 /*
                  * This page is now managed by the hugetlb allocator and has
                  * no users -- drop the buddy allocator's reference.
@@ -1009,7 +1011,6 @@ free:
         /* Free unnecessary surplus pages to the buddy allocator */
         if (!list_empty(&surplus_list)) {
                 list_for_each_entry_safe(page, tmp, &surplus_list, lru) {
-                        list_del(&page->lru);
                         put_page(page);
                 }
         }
@@ -1909,6 +1910,7 @@ void __init hugetlb_add_hstate(unsigned order)
         h->free_huge_pages = 0;
         for (i = 0; i < MAX_NUMNODES; ++i)
                 INIT_LIST_HEAD(&h->hugepage_freelists[i]);
+        INIT_LIST_HEAD(&h->hugepage_activelist);
         h->next_nid_to_alloc = first_node(node_states[N_HIGH_MEMORY]);
         h->next_nid_to_free = first_node(node_states[N_HIGH_MEMORY]);
         snprintf(h->name, HSTATE_NAME_LEN, "hugepages-%lukB",