mm: memcg: make memcg huge page split support any order split

It sets memcg information for the pages after the split. A new parameter new_order is added to tell the order of subpages in the new page, always 0 for now. It prepares for upcoming changes to support split huge page to any lower order. Link: https://lkml.kernel.org/r/[email protected] Signed-off-by: Zi Yan <[email protected]> Acked-by: David Hildenbrand <[email protected]> Cc: Hugh Dickins <[email protected]> Cc: Kirill A. Shutemov <[email protected]> Cc: Luis Chamberlain <[email protected]> Cc: "Matthew Wilcox (Oracle)" <[email protected]> Cc: Michal Koutny <[email protected]> Cc: Roman Gushchin <[email protected]> Cc: Ryan Roberts <[email protected]> Cc: Yang Shi <[email protected]> Cc: Yu Zhao <[email protected]> Cc: Zach O'Keefe <[email protected]> Signed-off-by: Andrew Morton <[email protected]>
torvalds · Mar 5, 2024 · b879138 · b879138
1 parent 9a581c1
commit b879138
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Showing 4 changed files with 11 additions and 10 deletions.
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
@@ -1163,7 +1163,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
  rcu_read_unlock();
 }
 
-void split_page_memcg(struct page *head, int order);
+void split_page_memcg(struct page *head, int old_order, int new_order);
 
 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
  gfp_t gfp_mask,
@@ -1621,7 +1621,7 @@ void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
 {
 }
 
-static inline void split_page_memcg(struct page *head, int order)
+static inline void split_page_memcg(struct page *head, int old_order, int new_order)
 {
 }
 

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
@@ -2894,7 +2894,7 @@ static void __split_huge_page(struct page *page, struct list_head *list,
  unsigned int nr = 1 << order;
 
  /* complete memcg works before add pages to LRU */
- split_page_memcg(head, order);
+ split_page_memcg(head, order, 0);
 
  if (folio_test_anon(folio) && folio_test_swapcache(folio)) {
  offset = swp_offset(folio->swap);

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
@@ -3606,23 +3606,24 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
 /*
  * Because page_memcg(head) is not set on tails, set it now.
  */
-void split_page_memcg(struct page *head, int order)
+void split_page_memcg(struct page *head, int old_order, int new_order)
 {
  struct folio *folio = page_folio(head);
  struct mem_cgroup *memcg = folio_memcg(folio);
  int i;
- unsigned int nr = 1 << order;
+ unsigned int old_nr = 1 << old_order;
+ unsigned int new_nr = 1 << new_order;
 
  if (mem_cgroup_disabled() || !memcg)
  return;
 
- for (i = 1; i < nr; i++)
+ for (i = new_nr; i < old_nr; i += new_nr)
  folio_page(folio, i)->memcg_data = folio->memcg_data;
 
  if (folio_memcg_kmem(folio))
- obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
+ obj_cgroup_get_many(__folio_objcg(folio), old_nr / new_nr - 1);
  else
- css_get_many(&memcg->css, nr - 1);
+ css_get_many(&memcg->css, old_nr / new_nr - 1);
 }
 
 #ifdef CONFIG_SWAP

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
@@ -2617,7 +2617,7 @@ void split_page(struct page *page, unsigned int order)
  for (i = 1; i < (1 << order); i++)
  set_page_refcounted(page + i);
  split_page_owner(page, order);
- split_page_memcg(page, order);
+ split_page_memcg(page, order, 0);
 }
 EXPORT_SYMBOL_GPL(split_page);
 
@@ -4802,7 +4802,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
  struct page *last = page + nr;
 
  split_page_owner(page, order);
- split_page_memcg(page, order);
+ split_page_memcg(page, order, 0);
  while (page < --last)
  set_page_refcounted(last);