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-rw-r--r--mm/memcontrol.c385
1 files changed, 238 insertions, 147 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index e46451e1d9b..36896f3eb7f 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -35,9 +35,9 @@
#include <asm/uaccess.h>
-struct cgroup_subsys mem_cgroup_subsys;
-static const int MEM_CGROUP_RECLAIM_RETRIES = 5;
-static struct kmem_cache *page_cgroup_cache;
+struct cgroup_subsys mem_cgroup_subsys __read_mostly;
+static struct kmem_cache *page_cgroup_cache __read_mostly;
+#define MEM_CGROUP_RECLAIM_RETRIES 5
/*
* Statistics for memory cgroup.
@@ -166,7 +166,6 @@ struct page_cgroup {
struct list_head lru; /* per cgroup LRU list */
struct page *page;
struct mem_cgroup *mem_cgroup;
- int ref_cnt; /* cached, mapped, migrating */
int flags;
};
#define PAGE_CGROUP_FLAG_CACHE (0x1) /* charged as cache */
@@ -185,6 +184,7 @@ static enum zone_type page_cgroup_zid(struct page_cgroup *pc)
enum charge_type {
MEM_CGROUP_CHARGE_TYPE_CACHE = 0,
MEM_CGROUP_CHARGE_TYPE_MAPPED,
+ MEM_CGROUP_CHARGE_TYPE_FORCE, /* used by force_empty */
};
/*
@@ -250,6 +250,14 @@ static struct mem_cgroup *mem_cgroup_from_cont(struct cgroup *cont)
struct mem_cgroup *mem_cgroup_from_task(struct task_struct *p)
{
+ /*
+ * mm_update_next_owner() may clear mm->owner to NULL
+ * if it races with swapoff, page migration, etc.
+ * So this can be called with p == NULL.
+ */
+ if (unlikely(!p))
+ return NULL;
+
return container_of(task_subsys_state(p, mem_cgroup_subsys_id),
struct mem_cgroup, css);
}
@@ -296,7 +304,7 @@ static void __mem_cgroup_remove_list(struct mem_cgroup_per_zone *mz,
MEM_CGROUP_ZSTAT(mz, MEM_CGROUP_ZSTAT_INACTIVE) -= 1;
mem_cgroup_charge_statistics(pc->mem_cgroup, pc->flags, false);
- list_del_init(&pc->lru);
+ list_del(&pc->lru);
}
static void __mem_cgroup_add_list(struct mem_cgroup_per_zone *mz,
@@ -354,6 +362,9 @@ void mem_cgroup_move_lists(struct page *page, bool active)
struct mem_cgroup_per_zone *mz;
unsigned long flags;
+ if (mem_cgroup_subsys.disabled)
+ return;
+
/*
* We cannot lock_page_cgroup while holding zone's lru_lock,
* because other holders of lock_page_cgroup can be interrupted
@@ -524,7 +535,8 @@ unsigned long mem_cgroup_isolate_pages(unsigned long nr_to_scan,
* < 0 if the cgroup is over its limit
*/
static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
- gfp_t gfp_mask, enum charge_type ctype)
+ gfp_t gfp_mask, enum charge_type ctype,
+ struct mem_cgroup *memcg)
{
struct mem_cgroup *mem;
struct page_cgroup *pc;
@@ -532,35 +544,8 @@ static int mem_cgroup_charge_common(struct page *page, struct mm_struct *mm,
unsigned long nr_retries = MEM_CGROUP_RECLAIM_RETRIES;
struct mem_cgroup_per_zone *mz;
- if (mem_cgroup_subsys.disabled)
- return 0;
-
- /*
- * Should page_cgroup's go to their own slab?
- * One could optimize the performance of the charging routine
- * by saving a bit in the page_flags and using it as a lock
- * to see if the cgroup page already has a page_cgroup associated
- * with it
- */
-retry:
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- /*
- * The page_cgroup exists and
- * the page has already been accounted.
- */
- if (pc) {
- VM_BUG_ON(pc->page != page);
- VM_BUG_ON(pc->ref_cnt <= 0);
-
- pc->ref_cnt++;
- unlock_page_cgroup(page);
- goto done;
- }
- unlock_page_cgroup(page);
-
- pc = kmem_cache_zalloc(page_cgroup_cache, gfp_mask);
- if (pc == NULL)
+ pc = kmem_cache_alloc(page_cgroup_cache, gfp_mask);
+ if (unlikely(pc == NULL))
goto err;
/*
@@ -569,16 +554,23 @@ retry:
* thread group leader migrates. It's possible that mm is not
* set, if so charge the init_mm (happens for pagecache usage).
*/
- if (!mm)
- mm = &init_mm;
-
- rcu_read_lock();
- mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
- /*
- * For every charge from the cgroup, increment reference count
- */
- css_get(&mem->css);
- rcu_read_unlock();
+ if (likely(!memcg)) {
+ rcu_read_lock();
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!mem)) {
+ rcu_read_unlock();
+ kmem_cache_free(page_cgroup_cache, pc);
+ return 0;
+ }
+ /*
+ * For every charge from the cgroup, increment reference count
+ */
+ css_get(&mem->css);
+ rcu_read_unlock();
+ } else {
+ mem = memcg;
+ css_get(&memcg->css);
+ }
while (res_counter_charge(&mem->res, PAGE_SIZE)) {
if (!(gfp_mask & __GFP_WAIT))
@@ -603,25 +595,24 @@ retry:
}
}
- pc->ref_cnt = 1;
pc->mem_cgroup = mem;
pc->page = page;
- pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
+ /*
+ * If a page is accounted as a page cache, insert to inactive list.
+ * If anon, insert to active list.
+ */
if (ctype == MEM_CGROUP_CHARGE_TYPE_CACHE)
pc->flags = PAGE_CGROUP_FLAG_CACHE;
+ else
+ pc->flags = PAGE_CGROUP_FLAG_ACTIVE;
lock_page_cgroup(page);
- if (page_get_page_cgroup(page)) {
+ if (unlikely(page_get_page_cgroup(page))) {
unlock_page_cgroup(page);
- /*
- * Another charge has been added to this page already.
- * We take lock_page_cgroup(page) again and read
- * page->cgroup, increment refcnt.... just retry is OK.
- */
res_counter_uncharge(&mem->res, PAGE_SIZE);
css_put(&mem->css);
kmem_cache_free(page_cgroup_cache, pc);
- goto retry;
+ goto done;
}
page_assign_page_cgroup(page, pc);
@@ -642,24 +633,65 @@ err:
int mem_cgroup_charge(struct page *page, struct mm_struct *mm, gfp_t gfp_mask)
{
+ if (mem_cgroup_subsys.disabled)
+ return 0;
+
+ /*
+ * If already mapped, we don't have to account.
+ * If page cache, page->mapping has address_space.
+ * But page->mapping may have out-of-use anon_vma pointer,
+ * detecit it by PageAnon() check. newly-mapped-anon's page->mapping
+ * is NULL.
+ */
+ 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);
+ MEM_CGROUP_CHARGE_TYPE_MAPPED, NULL);
}
int mem_cgroup_cache_charge(struct page *page, struct mm_struct *mm,
gfp_t gfp_mask)
{
- if (!mm)
+ if (mem_cgroup_subsys.disabled)
+ return 0;
+
+ /*
+ * Corner case handling. This is called from add_to_page_cache()
+ * in usual. But some FS (shmem) precharges this page before calling it
+ * and call add_to_page_cache() with GFP_NOWAIT.
+ *
+ * For GFP_NOWAIT case, the page may be pre-charged before calling
+ * add_to_page_cache(). (See shmem.c) check it here and avoid to call
+ * charge twice. (It works but has to pay a bit larger cost.)
+ */
+ if (!(gfp_mask & __GFP_WAIT)) {
+ struct page_cgroup *pc;
+
+ lock_page_cgroup(page);
+ pc = page_get_page_cgroup(page);
+ if (pc) {
+ VM_BUG_ON(pc->page != page);
+ VM_BUG_ON(!pc->mem_cgroup);
+ unlock_page_cgroup(page);
+ return 0;
+ }
+ unlock_page_cgroup(page);
+ }
+
+ if (unlikely(!mm))
mm = &init_mm;
+
return mem_cgroup_charge_common(page, mm, gfp_mask,
- MEM_CGROUP_CHARGE_TYPE_CACHE);
+ MEM_CGROUP_CHARGE_TYPE_CACHE, NULL);
}
/*
- * Uncharging is always a welcome operation, we never complain, simply
- * uncharge.
+ * uncharge if !page_mapped(page)
*/
-void mem_cgroup_uncharge_page(struct page *page)
+static void
+__mem_cgroup_uncharge_common(struct page *page, enum charge_type ctype)
{
struct page_cgroup *pc;
struct mem_cgroup *mem;
@@ -674,98 +706,158 @@ void mem_cgroup_uncharge_page(struct page *page)
*/
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
- if (!pc)
+ if (unlikely(!pc))
goto unlock;
VM_BUG_ON(pc->page != page);
- VM_BUG_ON(pc->ref_cnt <= 0);
- if (--(pc->ref_cnt) == 0) {
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_remove_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ if ((ctype == MEM_CGROUP_CHARGE_TYPE_MAPPED)
+ && ((pc->flags & PAGE_CGROUP_FLAG_CACHE)
+ || page_mapped(page)))
+ goto unlock;
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
+ mz = page_cgroup_zoneinfo(pc);
+ spin_lock_irqsave(&mz->lru_lock, flags);
+ __mem_cgroup_remove_list(mz, pc);
+ spin_unlock_irqrestore(&mz->lru_lock, flags);
- mem = pc->mem_cgroup;
- res_counter_uncharge(&mem->res, PAGE_SIZE);
- css_put(&mem->css);
+ page_assign_page_cgroup(page, NULL);
+ unlock_page_cgroup(page);
- kmem_cache_free(page_cgroup_cache, pc);
- return;
- }
+ mem = pc->mem_cgroup;
+ res_counter_uncharge(&mem->res, PAGE_SIZE);
+ css_put(&mem->css);
+ kmem_cache_free(page_cgroup_cache, pc);
+ return;
unlock:
unlock_page_cgroup(page);
}
+void mem_cgroup_uncharge_page(struct page *page)
+{
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_MAPPED);
+}
+
+void mem_cgroup_uncharge_cache_page(struct page *page)
+{
+ VM_BUG_ON(page_mapped(page));
+ __mem_cgroup_uncharge_common(page, MEM_CGROUP_CHARGE_TYPE_CACHE);
+}
+
/*
- * Returns non-zero if a page (under migration) has valid page_cgroup member.
- * Refcnt of page_cgroup is incremented.
+ * Before starting migration, account against new page.
*/
-int mem_cgroup_prepare_migration(struct page *page)
+int mem_cgroup_prepare_migration(struct page *page, struct page *newpage)
{
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)
return 0;
lock_page_cgroup(page);
pc = page_get_page_cgroup(page);
- if (pc)
- pc->ref_cnt++;
+ if (pc) {
+ mem = pc->mem_cgroup;
+ css_get(&mem->css);
+ if (pc->flags & PAGE_CGROUP_FLAG_CACHE)
+ ctype = MEM_CGROUP_CHARGE_TYPE_CACHE;
+ }
unlock_page_cgroup(page);
- return pc != NULL;
+ if (mem) {
+ ret = mem_cgroup_charge_common(newpage, NULL, GFP_KERNEL,
+ ctype, mem);
+ css_put(&mem->css);
+ }
+ return ret;
}
-void mem_cgroup_end_migration(struct page *page)
+/* remove redundant charge if migration failed*/
+void mem_cgroup_end_migration(struct page *newpage)
{
- mem_cgroup_uncharge_page(page);
+ /*
+ * 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.
+ */
+ if (!newpage->mapping)
+ __mem_cgroup_uncharge_common(newpage,
+ MEM_CGROUP_CHARGE_TYPE_FORCE);
+ else if (PageAnon(newpage))
+ mem_cgroup_uncharge_page(newpage);
}
/*
- * We know both *page* and *newpage* are now not-on-LRU and PG_locked.
- * And no race with uncharge() routines because page_cgroup for *page*
- * has extra one reference by mem_cgroup_prepare_migration.
+ * A call to try to shrink memory usage under specified resource controller.
+ * This is typically used for page reclaiming for shmem for reducing side
+ * effect of page allocation from shmem, which is used by some mem_cgroup.
*/
-void mem_cgroup_page_migration(struct page *page, struct page *newpage)
+int mem_cgroup_shrink_usage(struct mm_struct *mm, gfp_t gfp_mask)
{
- struct page_cgroup *pc;
- struct mem_cgroup_per_zone *mz;
- unsigned long flags;
+ struct mem_cgroup *mem;
+ int progress = 0;
+ int retry = MEM_CGROUP_RECLAIM_RETRIES;
- lock_page_cgroup(page);
- pc = page_get_page_cgroup(page);
- if (!pc) {
- unlock_page_cgroup(page);
- return;
+ if (mem_cgroup_subsys.disabled)
+ return 0;
+ if (!mm)
+ return 0;
+
+ rcu_read_lock();
+ mem = mem_cgroup_from_task(rcu_dereference(mm->owner));
+ if (unlikely(!mem)) {
+ rcu_read_unlock();
+ return 0;
}
+ css_get(&mem->css);
+ rcu_read_unlock();
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_remove_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ do {
+ progress = try_to_free_mem_cgroup_pages(mem, gfp_mask);
+ progress += res_counter_check_under_limit(&mem->res);
+ } while (!progress && --retry);
- page_assign_page_cgroup(page, NULL);
- unlock_page_cgroup(page);
+ css_put(&mem->css);
+ if (!retry)
+ return -ENOMEM;
+ return 0;
+}
- pc->page = newpage;
- lock_page_cgroup(newpage);
- page_assign_page_cgroup(newpage, pc);
+int mem_cgroup_resize_limit(struct mem_cgroup *memcg, unsigned long long val)
+{
- mz = page_cgroup_zoneinfo(pc);
- spin_lock_irqsave(&mz->lru_lock, flags);
- __mem_cgroup_add_list(mz, pc);
- spin_unlock_irqrestore(&mz->lru_lock, flags);
+ int retry_count = MEM_CGROUP_RECLAIM_RETRIES;
+ int progress;
+ int ret = 0;
- unlock_page_cgroup(newpage);
+ while (res_counter_set_limit(&memcg->res, val)) {
+ if (signal_pending(current)) {
+ ret = -EINTR;
+ break;
+ }
+ if (!retry_count) {
+ ret = -EBUSY;
+ break;
+ }
+ progress = try_to_free_mem_cgroup_pages(memcg, GFP_KERNEL);
+ if (!progress)
+ retry_count--;
+ }
+ return ret;
}
+
/*
* This routine traverse page_cgroup in given list and drop them all.
- * This routine ignores page_cgroup->ref_cnt.
* *And* this routine doesn't reclaim page itself, just removes page_cgroup.
*/
#define FORCE_UNCHARGE_BATCH (128)
@@ -790,12 +882,20 @@ static void mem_cgroup_force_empty_list(struct mem_cgroup *mem,
page = pc->page;
get_page(page);
spin_unlock_irqrestore(&mz->lru_lock, flags);
- mem_cgroup_uncharge_page(page);
- put_page(page);
- if (--count <= 0) {
- count = FORCE_UNCHARGE_BATCH;
+ /*
+ * Check if this page is on LRU. !LRU page can be found
+ * if it's under page migration.
+ */
+ if (PageLRU(page)) {
+ __mem_cgroup_uncharge_common(page,
+ MEM_CGROUP_CHARGE_TYPE_FORCE);
+ put_page(page);
+ if (--count <= 0) {
+ count = FORCE_UNCHARGE_BATCH;
+ cond_resched();
+ }
+ } else
cond_resched();
- }
spin_lock_irqsave(&mz->lru_lock, flags);
}
spin_unlock_irqrestore(&mz->lru_lock, flags);
@@ -810,9 +910,6 @@ static int mem_cgroup_force_empty(struct mem_cgroup *mem)
int ret = -EBUSY;
int node, zid;
- if (mem_cgroup_subsys.disabled)
- return 0;
-
css_get(&mem->css);
/*
* page reclaim code (kswapd etc..) will move pages between
@@ -838,32 +935,34 @@ out:
return ret;
}
-static int mem_cgroup_write_strategy(char *buf, unsigned long long *tmp)
-{
- *tmp = memparse(buf, &buf);
- if (*buf != '\0')
- return -EINVAL;
-
- /*
- * Round up the value to the closest page size
- */
- *tmp = ((*tmp + PAGE_SIZE - 1) >> PAGE_SHIFT) << PAGE_SHIFT;
- return 0;
-}
-
static u64 mem_cgroup_read(struct cgroup *cont, struct cftype *cft)
{
return res_counter_read_u64(&mem_cgroup_from_cont(cont)->res,
cft->private);
}
-
-static ssize_t mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
- struct file *file, const char __user *userbuf,
- size_t nbytes, loff_t *ppos)
+/*
+ * The user of this function is...
+ * RES_LIMIT.
+ */
+static int mem_cgroup_write(struct cgroup *cont, struct cftype *cft,
+ const char *buffer)
{
- return res_counter_write(&mem_cgroup_from_cont(cont)->res,
- cft->private, userbuf, nbytes, ppos,
- mem_cgroup_write_strategy);
+ struct mem_cgroup *memcg = mem_cgroup_from_cont(cont);
+ unsigned long long val;
+ int ret;
+
+ switch (cft->private) {
+ case RES_LIMIT:
+ /* This function does all necessary parse...reuse it */
+ ret = res_counter_memparse_write_strategy(buffer, &val);
+ if (!ret)
+ ret = mem_cgroup_resize_limit(memcg, val);
+ break;
+ default:
+ ret = -EINVAL; /* should be BUG() ? */
+ break;
+ }
+ return ret;
}
static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
@@ -940,7 +1039,7 @@ static struct cftype mem_cgroup_files[] = {
{
.name = "limit_in_bytes",
.private = RES_LIMIT,
- .write = mem_cgroup_write,
+ .write_string = mem_cgroup_write,
.read_u64 = mem_cgroup_read,
},
{
@@ -1070,8 +1169,6 @@ static void mem_cgroup_destroy(struct cgroup_subsys *ss,
static int mem_cgroup_populate(struct cgroup_subsys *ss,
struct cgroup *cont)
{
- if (mem_cgroup_subsys.disabled)
- return 0;
return cgroup_add_files(cont, ss, mem_cgroup_files,
ARRAY_SIZE(mem_cgroup_files));
}
@@ -1084,9 +1181,6 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct mm_struct *mm;
struct mem_cgroup *mem, *old_mem;
- if (mem_cgroup_subsys.disabled)
- return;
-
mm = get_task_mm(p);
if (mm == NULL)
return;
@@ -1094,9 +1188,6 @@ static void mem_cgroup_move_task(struct cgroup_subsys *ss,
mem = mem_cgroup_from_cont(cont);
old_mem = mem_cgroup_from_cont(old_cont);
- if (mem == old_mem)
- goto out;
-
/*
* Only thread group leaders are allowed to migrate, the mm_struct is
* in effect owned by the leader
generated by cgit v1.2.3-70-g09d2 (git 2.46.0) at 2024-12-25 10:22:15 +0000