The patch titled
Subject: mm/memcg: use order instead of nr in split_page_memcg()
has been added to the -mm mm-unstable branch. Its filename is
mm-memcg-use-order-instead-of-nr-in-split_page_memcg.patch
This patch will shortly appear at
https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-memcg-use-order-instead-of-nr-in-split_page_memcg.patch
This patch will later appear in the mm-unstable branch at
git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm
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------------------------------------------------------
From: Zi Yan <ziy@xxxxxxxxxx>
Subject: mm/memcg: use order instead of nr in split_page_memcg()
Date: Mon, 3 Apr 2023 16:18:33 -0400
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@xxxxxxxx
Link: https://lkml.kernel.org/r/20230403201839.4097845-2-zi.yan@xxxxxxxx
Signed-off-by: Zi Yan <ziy@xxxxxxxxxx>
Cc: Kirill A. Shutemov <kirill.shutemov@xxxxxxxxxxxxxxx>
Cc: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Cc: Michal Koutný <mkoutny@xxxxxxxx>
Cc: Roman Gushchin <roman.gushchin@xxxxxxxxx>
Cc: Ryan Roberts <ryan.roberts@xxxxxxx>
Cc: Yang Shi <shy828301@xxxxxxxxx>
Cc: Yu Zhao <yuzhao@xxxxxxxxxx>
Cc: Zach O'Keefe <zokeefe@xxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
include/linux/memcontrol.h | 4 ++--
mm/huge_memory.c | 3 ++-
mm/memcontrol.c | 3 ++-
mm/page_alloc.c | 4 ++--
4 files changed, 8 insertions(+), 6 deletions(-)
--- a/include/linux/memcontrol.h~mm-memcg-use-order-instead-of-nr-in-split_page_memcg
+++ a/include/linux/memcontrol.h
@@ -1152,7 +1152,7 @@ static inline void memcg_memory_event_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_stru
{
}
-static inline void split_page_memcg(struct page *head, unsigned int nr)
+static inline void split_page_memcg(struct page *head, int order)
{
}
--- a/mm/huge_memory.c~mm-memcg-use-order-instead-of-nr-in-split_page_memcg
+++ a/mm/huge_memory.c
@@ -2512,10 +2512,11 @@ static void __split_huge_page(struct pag
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) };
--- a/mm/memcontrol.c~mm-memcg-use-order-instead-of-nr-in-split_page_memcg
+++ a/mm/memcontrol.c
@@ -3441,11 +3441,12 @@ void obj_cgroup_uncharge(struct obj_cgro
/*
* 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;
--- a/mm/page_alloc.c~mm-memcg-use-order-instead-of-nr-in-split_page_memcg
+++ a/mm/page_alloc.c
@@ -2781,7 +2781,7 @@ void split_page(struct page *page, unsig
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 l
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);
_
Patches currently in -mm which might be from ziy@xxxxxxxxxx are
mm-memcg-use-order-instead-of-nr-in-split_page_memcg.patch
mm-page_owner-use-order-instead-of-nr-in-split_page_owner.patch
mm-memcg-make-memcg-huge-page-split-support-any-order-split.patch
mm-page_owner-add-support-for-splitting-to-any-order-in-split-page_owner.patch
mm-thp-split-huge-page-to-any-lower-order-pages.patch
mm-truncate-split-huge-page-cache-page-to-a-non-zero-order-if-possible.patch
mm-huge_memory-enable-debugfs-to-split-huge-pages-to-any-order.patch
