memcg information is only stored in the head page, so the memcg
subsystem needs to assure that all accesses are to the head page.
The first step is converting page_memcg() to folio_memcg().
The callers of page_memcg() and PageMemcgKmem() are not yet ready to be
converted to use folios, so retain them as wrappers around folio_memcg()
and folio_memcg_kmem(). They will be converted in a later patch set.
Signed-off-by: Matthew Wilcox (Oracle) <willy@xxxxxxxxxxxxx>
Reviewed-by: Christoph Hellwig <hch@xxxxxx>
---
include/linux/memcontrol.h | 109 ++++++++++++++++++++++---------------
mm/memcontrol.c | 21 ++++---
2 files changed, 77 insertions(+), 53 deletions(-)
diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index bfe5c486f4ad..f40c4e0b0431 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -372,6 +372,7 @@ enum page_memcg_data_flags {
#define MEMCG_DATA_FLAGS_MASK (__NR_MEMCG_DATA_FLAGS - 1)
static inline bool PageMemcgKmem(struct page *page);
+static inline bool folio_memcg_kmem(struct folio *folio);
/*
* After the initialization objcg->memcg is always pointing at
@@ -386,73 +387,77 @@ static inline struct mem_cgroup *obj_cgroup_memcg(struct obj_cgroup *objcg)
}
/*
- * __page_memcg - get the memory cgroup associated with a non-kmem page
- * @page: a pointer to the page struct
+ * __folio_memcg - Get the memory cgroup associated with a non-kmem folio
+ * @folio: Pointer to the folio.
*
- * Returns a pointer to the memory cgroup associated with the page,
- * or NULL. This function assumes that the page is known to have a
+ * Returns a pointer to the memory cgroup associated with the folio,
+ * or NULL. This function assumes that the folio is known to have a
* proper memory cgroup pointer. It's not safe to call this function
- * against some type of pages, e.g. slab pages or ex-slab pages or
- * kmem pages.
+ * against some type of folios, e.g. slab folios or ex-slab folios or
+ * kmem folios.
*/
-static inline struct mem_cgroup *__page_memcg(struct page *page)
+static inline struct mem_cgroup *__folio_memcg(struct folio *folio)
{
- unsigned long memcg_data = page->memcg_data;
+ unsigned long memcg_data = folio->memcg_data;
- VM_BUG_ON_PAGE(PageSlab(page), page);
- VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_OBJCGS, page);
- VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_KMEM, page);
+ VM_BUG_ON_FOLIO(folio_slab(folio), folio);
+ VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_OBJCGS, folio);
+ VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_KMEM, folio);
return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}
/*
- * __page_objcg - get the object cgroup associated with a kmem page
- * @page: a pointer to the page struct
+ * __folio_objcg - get the object cgroup associated with a kmem folio.
+ * @folio: Pointer to the folio.
*
- * Returns a pointer to the object cgroup associated with the page,
- * or NULL. This function assumes that the page is known to have a
+ * Returns a pointer to the object cgroup associated with the folio,
+ * or NULL. This function assumes that the folio is known to have a
* proper object cgroup pointer. It's not safe to call this function
- * against some type of pages, e.g. slab pages or ex-slab pages or
- * LRU pages.
+ * against some type of folios, e.g. slab folios or ex-slab folios or
+ * LRU folios.
*/
-static inline struct obj_cgroup *__page_objcg(struct page *page)
+static inline struct obj_cgroup *__folio_objcg(struct folio *folio)
{
- unsigned long memcg_data = page->memcg_data;
+ unsigned long memcg_data = folio->memcg_data;
- VM_BUG_ON_PAGE(PageSlab(page), page);
- VM_BUG_ON_PAGE(memcg_data & MEMCG_DATA_OBJCGS, page);
- VM_BUG_ON_PAGE(!(memcg_data & MEMCG_DATA_KMEM), page);
+ VM_BUG_ON_FOLIO(folio_slab(folio), folio);
+ VM_BUG_ON_FOLIO(memcg_data & MEMCG_DATA_OBJCGS, folio);
+ VM_BUG_ON_FOLIO(!(memcg_data & MEMCG_DATA_KMEM), folio);
return (struct obj_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}
/*
- * page_memcg - get the memory cgroup associated with a page
- * @page: a pointer to the page struct
+ * folio_memcg - Get the memory cgroup associated with a folio.
+ * @folio: Pointer to the folio.
*
- * Returns a pointer to the memory cgroup associated with the page,
- * or NULL. This function assumes that the page is known to have a
+ * Returns a pointer to the memory cgroup associated with the folio,
+ * or NULL. This function assumes that the folio is known to have a
* proper memory cgroup pointer. It's not safe to call this function
- * against some type of pages, e.g. slab pages or ex-slab pages.
+ * against some type of folios, e.g. slab folios or ex-slab folios.
*
- * For a non-kmem page any of the following ensures page and memcg binding
+ * For a non-kmem folio any of the following ensures folio and memcg binding
* stability:
*
- * - the page lock
+ * - the folio lock
* - LRU isolation
* - lock_page_memcg()
* - exclusive reference
*
- * For a kmem page a caller should hold an rcu read lock to protect memcg
- * associated with a kmem page from being released.
+ * For a kmem folio a caller should hold an rcu read lock to protect memcg
+ * associated with a kmem folio from being released.
*/
+static inline struct mem_cgroup *folio_memcg(struct folio *folio)
+{
+ if (folio_memcg_kmem(folio))
+ return obj_cgroup_memcg(__folio_objcg(folio));
+ return __folio_memcg(folio);
+}
+
static inline struct mem_cgroup *page_memcg(struct page *page)
{
- if (PageMemcgKmem(page))
- return obj_cgroup_memcg(__page_objcg(page));
- else
- return __page_memcg(page);
+ return folio_memcg(page_folio(page));
}
/*
@@ -525,17 +530,18 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page)
#ifdef CONFIG_MEMCG_KMEM
/*
- * PageMemcgKmem - check if the page has MemcgKmem flag set
- * @page: a pointer to the page struct
+ * folio_memcg_kmem - Check if the folio has the memcg_kmem flag set.
+ * @folio: Pointer to the folio.
*
- * Checks if the page has MemcgKmem flag set. The caller must ensure that
- * the page has an associated memory cgroup. It's not safe to call this function
- * against some types of pages, e.g. slab pages.
+ * Checks if the folio has MemcgKmem flag set. The caller must ensure
+ * that the folio has an associated memory cgroup. It's not safe to call
+ * this function against some types of folios, e.g. slab folios.
*/
-static inline bool PageMemcgKmem(struct page *page)
+static inline bool folio_memcg_kmem(struct folio *folio)
{
- VM_BUG_ON_PAGE(page->memcg_data & MEMCG_DATA_OBJCGS, page);
- return page->memcg_data & MEMCG_DATA_KMEM;
+ VM_BUG_ON_PGFLAGS(PageTail(&folio->page), &folio->page);
+ VM_BUG_ON_FOLIO(folio->memcg_data & MEMCG_DATA_OBJCGS, folio);
+ return folio->memcg_data & MEMCG_DATA_KMEM;
}
/*
@@ -579,7 +585,7 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page)
}
#else
-static inline bool PageMemcgKmem(struct page *page)
+static inline bool folio_memcg_kmem(struct folio *folio)
{
return false;
}
@@ -595,6 +601,11 @@ static inline struct obj_cgroup **page_objcgs_check(struct page *page)
}
#endif
+static inline bool PageMemcgKmem(struct page *page)
+{
+ return folio_memcg_kmem(page_folio(page));
+}
+
static __always_inline bool memcg_stat_item_in_bytes(int idx)
{
if (idx == MEMCG_PERCPU_B)
@@ -1106,6 +1117,11 @@ unsigned long mem_cgroup_soft_limit_reclaim(pg_data_t *pgdat, int order,
#define MEM_CGROUP_ID_SHIFT 0
#define MEM_CGROUP_ID_MAX 0
+static inline struct mem_cgroup *folio_memcg(struct folio *folio)
+{
+ return NULL;
+}
+
static inline struct mem_cgroup *page_memcg(struct page *page)
{
return NULL;
@@ -1122,6 +1138,11 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page)
return NULL;
}
+static inline bool folio_memcg_kmem(struct folio *folio)
+{
+ return false;
+}
+
static inline bool PageMemcgKmem(struct page *page)
{
return false;
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index 1a049bfa0e0a..f0f781dde37a 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -3050,15 +3050,16 @@ int __memcg_kmem_charge_page(struct page *page, gfp_t gfp, int order)
*/
void __memcg_kmem_uncharge_page(struct page *page, int order)
{
+ struct folio *folio = page_folio(page);
struct obj_cgroup *objcg;
unsigned int nr_pages = 1 << order;
- if (!PageMemcgKmem(page))
+ if (!folio_memcg_kmem(folio))
return;
- objcg = __page_objcg(page);
+ objcg = __folio_objcg(folio);
obj_cgroup_uncharge_pages(objcg, nr_pages);
- page->memcg_data = 0;
+ folio->memcg_data = 0;
obj_cgroup_put(objcg);
}
@@ -3290,17 +3291,18 @@ void obj_cgroup_uncharge(struct obj_cgroup *objcg, size_t size)
*/
void split_page_memcg(struct page *head, unsigned int nr)
{
- struct mem_cgroup *memcg = page_memcg(head);
+ struct folio *folio = page_folio(head);
+ struct mem_cgroup *memcg = folio_memcg(folio);
int i;
if (mem_cgroup_disabled() || !memcg)
return;
for (i = 1; i < nr; i++)
- head[i].memcg_data = head->memcg_data;
+ folio_page(folio, i)->memcg_data = folio->memcg_data;
- if (PageMemcgKmem(head))
- obj_cgroup_get_many(__page_objcg(head), nr - 1);
+ if (folio_memcg_kmem(folio))
+ obj_cgroup_get_many(__folio_objcg(folio), nr - 1);
else
css_get_many(&memcg->css, nr - 1);
}
@@ -6835,6 +6837,7 @@ static void uncharge_batch(const struct uncharge_gather *ug)
static void uncharge_page(struct page *page, struct uncharge_gather *ug)
{
+ struct folio *folio = page_folio(page);
unsigned long nr_pages;
struct mem_cgroup *memcg;
struct obj_cgroup *objcg;
@@ -6848,14 +6851,14 @@ static void uncharge_page(struct page *page, struct uncharge_gather *ug)
* exclusive access to the page.
*/
if (use_objcg) {
- objcg = __page_objcg(page);
+ objcg = __folio_objcg(folio);
/*
* This get matches the put at the end of the function and
* kmem pages do not hold memcg references anymore.
*/
memcg = get_mem_cgroup_from_objcg(objcg);
} else {
- memcg = __page_memcg(page);
+ memcg = __folio_memcg(folio);
}
if (!memcg)
--
2.30.2
