[PATCH v14 041/138] mm/memcg: Convert uncharge_page() to uncharge_folio()

Matthew Wilcox (Oracle)
2021-07-15T04:11:22Z

Use a folio rather than a page to ensure that we're only operating on
base or head pages, and not tail pages.

Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Reviewed-by: Christoph Hellwig <hch@lst.de>
---
mm/memcontrol.c | 29 ++++++++++++++---------------
1 file changed, 14 insertions(+), 15 deletions(-)

diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 03283d97b62a..c257cb71a3b0 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -6832,24 +6832,23 @@ static void uncharge_batch(const struct uncharge_gather *ug)
memcg_check_events(ug->memcg, ug->nid);
local_irq_restore(flags);

- /* drop reference from uncharge_page */
+ /* drop reference from uncharge_folio */
css_put(&ug->memcg->css);
}

-static void uncharge_page(struct page *page, struct uncharge_gather *ug)
+static void uncharge_folio(struct folio *folio, struct uncharge_gather *ug)
{
- struct folio *folio = page_folio(page);
unsigned long nr_pages;
struct mem_cgroup *memcg;
struct obj_cgroup *objcg;
- bool use_objcg = PageMemcgKmem(page);
+ bool use_objcg = folio_memcg_kmem(folio);

- VM_BUG_ON_PAGE(PageLRU(page), page);
+ VM_BUG_ON_FOLIO(folio_test_lru(folio), folio);

/*
* Nobody should be changing or seriously looking at
- * page memcg or objcg at this point, we have fully
- * exclusive access to the page.
+ * folio memcg or objcg at this point, we have fully
+ * exclusive access to the folio.
*/
if (use_objcg) {
objcg = __folio_objcg(folio);
@@ -6871,19 +6870,19 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
uncharge_gather_clear(ug);
}
ug->memcg = memcg;
- ug->nid = page_to_nid(page);
+ ug->nid = folio_nid(folio);

/* pairs with css_put in uncharge_batch */
css_get(&memcg->css);
}

- nr_pages = compound_nr(page);
+ nr_pages = folio_nr_pages(folio);

if (use_objcg) {
ug->nr_memory += nr_pages;
ug->nr_kmem += nr_pages;

- page->memcg_data = 0;
+ folio->memcg_data = 0;
obj_cgroup_put(objcg);
} else {
/* LRU pages aren't accounted at the root level */
@@ -6891,7 +6890,7 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
ug->nr_memory += nr_pages;
ug->pgpgout++;

- page->memcg_data = 0;
+ folio->memcg_data = 0;
}

css_put(&memcg->css);
@@ -6915,7 +6914,7 @@ void mem_cgroup_uncharge(struct page *page)
return;

uncharge_gather_clear(&ug);
- uncharge_page(page, &ug);
+ uncharge_folio(page_folio(page), &ug);
uncharge_batch(&ug);
}

@@ -6929,14 +6928,14 @@ void mem_cgroup_uncharge(struct page *page)
void mem_cgroup_uncharge_list(struct list_head *page_list)
{
struct uncharge_gather ug;
- struct page *page;
+ struct folio *folio;

if (mem_cgroup_disabled())
return;

uncharge_gather_clear(&ug);
- list_for_each_entry(page, page_list, lru)
- uncharge_page(page, &ug);
+ list_for_each_entry(folio, page_list, lru)
+ uncharge_folio(folio, &ug);
if (ug.memcg)
uncharge_batch(&ug);
}
--
2.30.2