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mm: memcg: add folio_memcg_check()

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Patch series "mm: convert page_idle/damon to use folios", v4.


This patch (of 8):

Convert page_memcg_check() into folio_memcg_check() and add a
page_memcg_check() wrapper.  The behaviour of page_memcg_check() is
unchanged; tail pages always had a NULL ->memcg_data.

Link: https://lkml.kernel.org/r/20221230070849.63358-1-wangkefeng.wang@huawei.com
Link: https://lkml.kernel.org/r/20221230070849.63358-2-wangkefeng.wang@huawei.com
Signed-off-by: Matthew Wilcox (Oracle) <willy@infradead.org>
Signed-off-by: Kefeng Wang <wangkefeng.wang@huawei.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: SeongJae Park <sj@kernel.org>
Cc: Vishal Moola (Oracle) <vishal.moola@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
This commit is contained in:
Matthew Wilcox 2022-12-30 15:08:42 +08:00 committed by Andrew Morton
parent 071acb3084
commit becacb04fd
2 changed files with 29 additions and 17 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

40
include/linux/memcontrol.h
View File

@ -466,34 +466,34 @@ static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio)
}
/*
* page_memcg_check - get the memory cgroup associated with a page
* @page: a pointer to the page struct
* folio_memcg_check - 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 unlike page_memcg() can take any page
* as an argument. It has to be used in cases when it's not known if a page
* Returns a pointer to the memory cgroup associated with the folio,
* or NULL. This function unlike folio_memcg() can take any folio
* as an argument. It has to be used in cases when it's not known if a folio
* has an associated memory cgroup pointer or an object cgroups vector or
* an object cgroup.
*
* 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()
* - lock_folio_memcg()
* - exclusive reference
* - mem_cgroup_trylock_pages()
*
* 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 *page_memcg_check(struct page *page)
static inline struct mem_cgroup *folio_memcg_check(struct folio *folio)
{
/*
* Because page->memcg_data might be changed asynchronously
* for slab pages, READ_ONCE() should be used here.
* Because folio->memcg_data might be changed asynchronously
* for slabs, READ_ONCE() should be used here.
*/
unsigned long memcg_data = READ_ONCE(page->memcg_data);
unsigned long memcg_data = READ_ONCE(folio->memcg_data);
if (memcg_data & MEMCG_DATA_OBJCGS)
return NULL;
@ -508,6 +508,13 @@ static inline struct mem_cgroup *page_memcg_check(struct page *page)
return (struct mem_cgroup *)(memcg_data & ~MEMCG_DATA_FLAGS_MASK);
}
static inline struct mem_cgroup *page_memcg_check(struct page *page)
{
if (PageTail(page))
return NULL;
return folio_memcg_check((struct folio *)page);
}
static inline struct mem_cgroup *get_mem_cgroup_from_objcg(struct obj_cgroup *objcg)
{
struct mem_cgroup *memcg;
@ -1170,6 +1177,11 @@ static inline struct mem_cgroup *folio_memcg_rcu(struct folio *folio)
return NULL;
}
static inline struct mem_cgroup *folio_memcg_check(struct folio *folio)
{
return NULL;
}
static inline struct mem_cgroup *page_memcg_check(struct page *page)
{
return NULL;

6
mm/memcontrol.c
View File

@ -2952,13 +2952,13 @@ struct mem_cgroup *mem_cgroup_from_obj_folio(struct folio *folio, void *p)
}
/*
* page_memcg_check() is used here, because in theory we can encounter
* folio_memcg_check() is used here, because in theory we can encounter
* a folio where the slab flag has been cleared already, but
* slab->memcg_data has not been freed yet
* page_memcg_check(page) will guarantee that a proper memory
* folio_memcg_check() will guarantee that a proper memory
* cgroup pointer or NULL will be returned.
*/
return page_memcg_check(folio_page(folio, 0));
return folio_memcg_check(folio);
}
/*