mirror of
https://mirrors.bfsu.edu.cn/git/linux.git
synced 2024-11-24 20:54:10 +08:00
memcg: simple migration handling
Now, management of "charge" under page migration is done under following
manner. (Assume migrate page contents from oldpage to newpage)
before
- "newpage" is charged before migration.
at success.
- "oldpage" is uncharged at somewhere(unmap, radix-tree-replace)
at failure
- "newpage" is uncharged.
- "oldpage" is charged if necessary (*1)
But (*1) is not reliable....because of GFP_ATOMIC.
This patch tries to change behavior as following by charge/commit/cancel ops.
before
- charge PAGE_SIZE (no target page)
success
- commit charge against "newpage".
failure
- commit charge against "oldpage".
(PCG_USED bit works effectively to avoid double-counting)
- if "oldpage" is obsolete, cancel charge of PAGE_SIZE.
Signed-off-by: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Reviewed-by: Daisuke Nishimura <nishimura@mxp.nes.nec.co.jp>
Cc: Balbir Singh <balbir@in.ibm.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
This commit is contained in:
KAMEZAWA Hiroyuki
Linus Torvalds
parent
bced0520fe
commit
01b1ae63c2
@ -29,8 +29,6 @@ struct mm_struct;
|
||||
|
||||
extern int mem_cgroup_newpage_charge(struct page *page, struct mm_struct *mm,
|
||||
gfp_t gfp_mask);
|
||||
extern int mem_cgroup_charge_migrate_fixup(struct page *page,
|
||||
struct mm_struct *mm, gfp_t gfp_mask);
|
||||
/* for swap handling */
|
||||
extern int mem_cgroup_try_charge(struct mm_struct *mm,
|
||||
gfp_t gfp_mask, struct mem_cgroup **ptr);
|
||||
@ -60,8 +58,9 @@ extern struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p);
|
||||
((cgroup) == mem_cgroup_from_task((mm)->owner))
|
||||
|
||||
extern int
|
||||
mem_cgroup_prepare_migration(struct page *page, struct page *newpage);
|
||||
extern void mem_cgroup_end_migration(struct page *page);
|
||||
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr);
|
||||
extern void mem_cgroup_end_migration(struct mem_cgroup *mem,
|
||||
struct page *oldpage, struct page *newpage);
|
||||
|
||||
/*
|
||||
* For memory reclaim.
|
||||
@ -94,12 +93,6 @@ static inline int mem_cgroup_cache_charge(struct page *page,
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline int mem_cgroup_charge_migrate_fixup(struct page *page,
|
||||
struct mm_struct *mm, gfp_t gfp_mask)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline int mem_cgroup_try_charge(struct mm_struct *mm,
|
||||
gfp_t gfp_mask, struct mem_cgroup **ptr)
|
||||
{
|
||||
@ -144,12 +137,14 @@ static inline int task_in_mem_cgroup(struct task_struct *task,
|
||||
}
|
||||
|
||||
static inline int
|
||||
mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
|
||||
mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
|
||||
{
|
||||
return 0;
|
||||
}
|
||||
|
||||
static inline void mem_cgroup_end_migration(struct page *page)
|
||||
static inline void mem_cgroup_end_migration(struct mem_cgroup *mem,
|
||||
struct page *oldpage,
|
||||
struct page *newpage)
|
||||
{
|
||||
}
|
||||
|
||||
|
||||
108
mm/memcontrol.c
108
mm/memcontrol.c
@ -627,34 +627,6 @@ int mem_cgroup_newpage_charge(struct page *page,
|
||||
MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
|
||||
}
|
||||
|
||||
/*
|
||||
* same as mem_cgroup_newpage_charge(), now.
|
||||
* But what we assume is different from newpage, and this is special case.
|
||||
* treat this in special function. easy for maintenance.
|
||||
*/
|
||||
|
||||
int mem_cgroup_charge_migrate_fixup(struct page *page,
|
||||
struct mm_struct *mm, gfp_t gfp_mask)
|
||||
{
|
||||
if (mem_cgroup_subsys.disabled)
|
||||
return 0;
|
||||
|
||||
if (PageCompound(page))
|
||||
return 0;
|
||||
|
||||
if (page_mapped(page) || (page->mapping && !PageAnon(page)))
|
||||
return 0;
|
||||
|
||||
if (unlikely(!mm))
|
||||
mm = &init_mm;
|
||||
|
||||
return mem_cgroup_charge_common(page, mm, gfp_mask,
|
||||
MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
|
||||
}
|
||||
|
||||
|
||||
|
||||
|
||||
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
|
||||
gfp_t gfp_mask)
|
||||
{
|
||||
@ -697,7 +669,6 @@ int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
|
||||
MEM_CGROUP_CHARGE_TYPE_SHMEM, NULL);
|
||||
}
|
||||
|
||||
|
||||
void mem_cgroup_commit_charge_swapin(struct page *page, struct mem_cgroup *ptr)
|
||||
{
|
||||
struct page_cgroup *pc;
|
||||
@ -782,13 +753,13 @@ void mem_cgroup_uncharge_cache_page(struct page *page)
|
||||
}
|
||||
|
||||
/*
|
||||
* Before starting migration, account against new page.
|
||||
* Before starting migration, account PAGE_SIZE to mem_cgroup that the old
|
||||
* page belongs to.
|
||||
*/
|
||||
int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
|
||||
int mem_cgroup_prepare_migration(struct page *page, struct mem_cgroup **ptr)
|
||||
{
|
||||
struct page_cgroup *pc;
|
||||
struct mem_cgroup *mem = NULL;
|
||||
enum charge_type ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
|
||||
int ret = 0;
|
||||
|
||||
if (mem_cgroup_subsys.disabled)
|
||||
@ -799,42 +770,67 @@ int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
|
||||
if (PageCgroupUsed(pc)) {
|
||||
mem = pc->mem_cgroup;
|
||||
css_get(&mem->css);
|
||||
if (PageCgroupCache(pc)) {
|
||||
if (page_is_file_cache(page))
|
||||
ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
|
||||
else
|
||||
ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
|
||||
}
|
||||
}
|
||||
unlock_page_cgroup(pc);
|
||||
|
||||
if (mem) {
|
||||
ret = mem_cgroup_charge_common(newpage, NULL,
|
||||
GFP_HIGHUSER_MOVABLE,
|
||||
ctype, mem);
|
||||
ret = mem_cgroup_try_charge(NULL, GFP_HIGHUSER_MOVABLE, &mem);
|
||||
css_put(&mem->css);
|
||||
}
|
||||
*ptr = mem;
|
||||
return ret;
|
||||
}
|
||||
|
||||
/* remove redundant charge if migration failed*/
|
||||
void mem_cgroup_end_migration(struct page *newpage)
|
||||
void mem_cgroup_end_migration(struct mem_cgroup *mem,
|
||||
struct page *oldpage, struct page *newpage)
|
||||
{
|
||||
struct page *target, *unused;
|
||||
struct page_cgroup *pc;
|
||||
enum charge_type ctype;
|
||||
|
||||
if (!mem)
|
||||
return;
|
||||
|
||||
/* at migration success, oldpage->mapping is NULL. */
|
||||
if (oldpage->mapping) {
|
||||
target = oldpage;
|
||||
unused = NULL;
|
||||
} else {
|
||||
target = newpage;
|
||||
unused = oldpage;
|
||||
}
|
||||
|
||||
if (PageAnon(target))
|
||||
ctype = MEM_CGROUP_CHARGE_TYPE_MAPPED;
|
||||
else if (page_is_file_cache(target))
|
||||
ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
|
||||
else
|
||||
ctype = MEM_CGROUP_CHARGE_TYPE_SHMEM;
|
||||
|
||||
/* unused page is not on radix-tree now. */
|
||||
if (unused && ctype != MEM_CGROUP_CHARGE_TYPE_MAPPED)
|
||||
__mem_cgroup_uncharge_common(unused, ctype);
|
||||
|
||||
pc = lookup_page_cgroup(target);
|
||||
/*
|
||||
* At success, page->mapping is not NULL.
|
||||
* special rollback care is necessary when
|
||||
* 1. at migration failure. (newpage->mapping is cleared in this case)
|
||||
* 2. the newpage was moved but not remapped again because the task
|
||||
* exits and the newpage is obsolete. In this case, the new page
|
||||
* may be a swapcache. So, we just call mem_cgroup_uncharge_page()
|
||||
* always for avoiding mess. The page_cgroup will be removed if
|
||||
* unnecessary. File cache pages is still on radix-tree. Don't
|
||||
* care it.
|
||||
* __mem_cgroup_commit_charge() check PCG_USED bit of page_cgroup.
|
||||
* So, double-counting is effectively avoided.
|
||||
*/
|
||||
if (!newpage->mapping)
|
||||
__mem_cgroup_uncharge_common(newpage,
|
||||
MEM_CGROUP_CHARGE_TYPE_FORCE);
|
||||
else if (PageAnon(newpage))
|
||||
mem_cgroup_uncharge_page(newpage);
|
||||
__mem_cgroup_commit_charge(mem, pc, ctype);
|
||||
|
||||
/*
|
||||
* Both of oldpage and newpage are still under lock_page().
|
||||
* Then, we don't have to care about race in radix-tree.
|
||||
* But we have to be careful that this page is unmapped or not.
|
||||
*
|
||||
* There is a case for !page_mapped(). At the start of
|
||||
* migration, oldpage was mapped. But now, it's zapped.
|
||||
* But we know *target* page is not freed/reused under us.
|
||||
* mem_cgroup_uncharge_page() does all necessary checks.
|
||||
*/
|
||||
if (ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
|
||||
mem_cgroup_uncharge_page(target);
|
||||
}
|
||||
|
||||
/*
|
||||
|
||||
42
mm/migrate.c
42
mm/migrate.c
@ -121,20 +121,6 @@ static void remove_migration_pte(struct vm_area_struct *vma,
|
||||
if (!is_migration_entry(entry) || migration_entry_to_page(entry) != old)
|
||||
goto out;
|
||||
|
||||
/*
|
||||
* Yes, ignore the return value from a GFP_ATOMIC mem_cgroup_charge.
|
||||
* Failure is not an option here: we're now expected to remove every
|
||||
* migration pte, and will cause crashes otherwise. Normally this
|
||||
* is not an issue: mem_cgroup_prepare_migration bumped up the old
|
||||
* page_cgroup count for safety, that's now attached to the new page,
|
||||
* so this charge should just be another incrementation of the count,
|
||||
* to keep in balance with rmap.c's mem_cgroup_uncharging. But if
|
||||
* there's been a force_empty, those reference counts may no longer
|
||||
* be reliable, and this charge can actually fail: oh well, we don't
|
||||
* make the situation any worse by proceeding as if it had succeeded.
|
||||
*/
|
||||
mem_cgroup_charge_migrate_fixup(new, mm, GFP_ATOMIC);
|
||||
|
||||
get_page(new);
|
||||
pte = pte_mkold(mk_pte(new, vma->vm_page_prot));
|
||||
if (is_write_migration_entry(entry))
|
||||
@ -378,9 +364,6 @@ static void migrate_page_copy(struct page *newpage, struct page *page)
|
||||
anon = PageAnon(page);
|
||||
page->mapping = NULL;
|
||||
|
||||
if (!anon) /* This page was removed from radix-tree. */
|
||||
mem_cgroup_uncharge_cache_page(page);
|
||||
|
||||
/*
|
||||
* If any waiters have accumulated on the new page then
|
||||
* wake them up.
|
||||
@ -614,6 +597,7 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
|
||||
struct page *newpage = get_new_page(page, private, &result);
|
||||
int rcu_locked = 0;
|
||||
int charge = 0;
|
||||
struct mem_cgroup *mem;
|
||||
|
||||
if (!newpage)
|
||||
return -ENOMEM;
|
||||
@ -623,24 +607,26 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
|
||||
goto move_newpage;
|
||||
}
|
||||
|
||||
charge = mem_cgroup_prepare_migration(page, newpage);
|
||||
if (charge == -ENOMEM) {
|
||||
rc = -ENOMEM;
|
||||
goto move_newpage;
|
||||
}
|
||||
/* prepare cgroup just returns 0 or -ENOMEM */
|
||||
BUG_ON(charge);
|
||||
|
||||
rc = -EAGAIN;
|
||||
|
||||
if (!trylock_page(page)) {
|
||||
if (!force)
|
||||
goto move_newpage;
|
||||
lock_page(page);
|
||||
}
|
||||
|
||||
/* charge against new page */
|
||||
charge = mem_cgroup_prepare_migration(page, &mem);
|
||||
if (charge == -ENOMEM) {
|
||||
rc = -ENOMEM;
|
||||
goto unlock;
|
||||
}
|
||||
BUG_ON(charge);
|
||||
|
||||
if (PageWriteback(page)) {
|
||||
if (!force)
|
||||
goto unlock;
|
||||
goto uncharge;
|
||||
wait_on_page_writeback(page);
|
||||
}
|
||||
/*
|
||||
@ -693,7 +679,9 @@ static int unmap_and_move(new_page_t get_new_page, unsigned long private,
|
||||
rcu_unlock:
|
||||
if (rcu_locked)
|
||||
rcu_read_unlock();
|
||||
|
||||
uncharge:
|
||||
if (!charge)
|
||||
mem_cgroup_end_migration(mem, page, newpage);
|
||||
unlock:
|
||||
unlock_page(page);
|
||||
|
||||
@ -709,8 +697,6 @@ unlock:
|
||||
}
|
||||
|
||||
move_newpage:
|
||||
if (!charge)
|
||||
mem_cgroup_end_migration(newpage);
|
||||
|
||||
/*
|
||||
* Move the new page to the LRU. If migration was not successful
|
||||
|
||||
Loading…
Reference in New Issue
Block a user