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/20240226205534.1603748-6-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Acked-by: David Hildenbrand <david@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Luis Chamberlain <mcgrof@kernel.org>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Michal Koutny <mkoutny@suse.com>
Cc: Roman Gushchin <roman.gushchin@linux.dev>
Cc: Ryan Roberts <ryan.roberts@arm.com>
Cc: Yang Shi <shy828301@gmail.com>
Cc: Yu Zhao <yuzhao@google.com>
Cc: Zach O'Keefe <zokeefe@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 173bbb53c1ec707df8ceb4a13a465294750608ad..9a2dea92be0e85967d580a7089600ed7b2186c38 100644 (file)
--- 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
index 2b95dbc95fae418a5250baa0cdc8d9980f02ad85..5d4b7c17b9bc328d0f46c81599f85fcd16e279a9 100644 (file)
--- 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
index db9a3fb26a996179f208609d2a71646d02b35f12..e4864e2729e6be13e8c67db1796028f1f256443f 100644 (file)
--- 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
index a9d1af34f4d68191e1e6d79296a4a07c58c3be12..3b3dae66d49da9e83a9a6fd05993e2a923cb380d 100644 (file)
--- 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);