mm/memcg: use order instead of nr in split_page_memcg()

Patch series "Split a folio to any lower order folios", v3.

File folio supports any order and people would like to support flexible
orders for anonymous folio[1] too.  Currently, split_huge_page() only
splits a huge page to order-0 pages, but splitting to orders higher than 0
is also useful.  This patchset adds support for splitting a huge page to
any lower order pages and uses it during file folio truncate operations.

This patch (of 7):

We do not have non power of two pages, using nr is error prone if nr is
not power-of-two.  Use page order instead.

Link: https://lkml.kernel.org/r/20230403201839.4097845-1-zi.yan@sent.com
Link: https://lkml.kernel.org/r/20230403201839.4097845-2-zi.yan@sent.com
Signed-off-by: Zi Yan <ziy@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michal Koutný <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 222d7370134c73e59fdbdf598ed8d66897dbbf1d..958838c4c91516e76e30c2b575b4738d5d3e7550 100644 (file)
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -1152,7 +1152,7 @@ static inline void memcg_memory_event_mm(struct mm_struct *mm,
        rcu_read_unlock();
 }
 
-void split_page_memcg(struct page *head, unsigned int nr);
+void split_page_memcg(struct page *head, int order);
 
 unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
                                                gfp_t gfp_mask,
@@ -1593,7 +1593,7 @@ void count_memcg_event_mm(struct mm_struct *mm, enum vm_event_item idx)
 {
 }
 
-static inline void split_page_memcg(struct page *head, unsigned int nr)
+static inline void split_page_memcg(struct page *head, int order)
 {
 }
 

diff --git a/mm/huge_memory.c b/mm/huge_memory.c
index 37f0f7fd554919998f0ce4a3754064eabc992cfd..82a875a61d735753bfe71bd3e40e59bcdb58cd5d 100644 (file)
--- a/mm/huge_memory.c
+++ b/mm/huge_memory.c
@@ -2520,10 +2520,11 @@ static void __split_huge_page(struct page *page, struct list_head *list,
        struct address_space *swap_cache = NULL;
        unsigned long offset = 0;
        unsigned int nr = thp_nr_pages(head);
+       int order = folio_order(folio);
        int i;
 
        /* complete memcg works before add pages to LRU */
-       split_page_memcg(head, nr);
+       split_page_memcg(head, order);
 
        if (PageAnon(head) && PageSwapCache(head)) {
                swp_entry_t entry = { .val = page_private(head) };

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index cb17f3abdfe0905aa3acabb8344180243659abe2..42248f0bf4021c65a3054f2be683a627fb25b698 100644 (file)
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3441,11 +3441,12 @@ 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, unsigned int nr)
+void split_page_memcg(struct page *head, int order)
 {
        struct folio *folio = page_folio(head);
        struct mem_cgroup *memcg = folio_memcg(folio);
        int i;
+       unsigned int nr = 1 << order;
 
        if (mem_cgroup_disabled() || !memcg)
                return;

diff --git a/mm/page_alloc.c b/mm/page_alloc.c
index 9ddb3ccb867956f83341542246f13f5dc6a14bb2..0fe6404289c93eb5c55c7a23294d8a025a0ad33a 100644 (file)
--- a/mm/page_alloc.c
+++ b/mm/page_alloc.c
@@ -2781,7 +2781,7 @@ 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, 1 << order);
-       split_page_memcg(page, 1 << order);
+       split_page_memcg(page, order);
 }
 EXPORT_SYMBOL_GPL(split_page);
 
@@ -4997,7 +4997,7 @@ static void *make_alloc_exact(unsigned long addr, unsigned int order,
                struct page *last = page + nr;
 
                split_page_owner(page, 1 << order);
-               split_page_memcg(page, 1 << order);
+               split_page_memcg(page, order);
                while (page < --last)
                        set_page_refcounted(last);