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authorYunhong Jiang <yunhong.jiang@linux.intel.com>2017-03-08 23:13:28 -0800
committerYunhong Jiang <yunhong.jiang@linux.intel.com>2017-03-08 23:36:15 -0800
commit52f993b8e89487ec9ee15a7fb4979e0f09a45b27 (patch)
treed65304486afe0bea4a311c783c0d72791c8c0aa2 /kernel/mm/memcontrol.c
parentc189ccac5702322ed843fe17057035b7222a59b6 (diff)
Upgrade to 4.4.50-rt62
The current kernel is based on rt kernel v4.4.6-rt14. We will upgrade it to 4.4.50-rt62. The command to achieve it is: a) Clone a git repo from git://git.kernel.org/pub/scm/linux/kernel/git/rt/linux-stable-rt.git b) Get the diff between this two changesets: git diff 640eca2901f3435e616157b11379d3223a44b391 705619beeea1b0b48219a683fd1a901a86fdaf5e where the two commits are: [yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only 640eca2901f3435e616157b11379d3223a44b391 640eca2901f3 v4.4.6-rt14 localversion-rt [yjiang5@jnakajim-build linux-stable-rt]$ git show --oneline --name-only 705619beeea1b0b48219a683fd1a901a86fdaf5e 705619beeea1 Linux 4.4.50-rt62 localversion-rt c) One patch has been backported thus revert the patch before applying. filterdiff -p1 -x scripts/package/Makefile ~/tmp/v4.4.6-rt14-4.4.50-rt62.diff |patch -p1 --dry-run Upstream status: backport Change-Id: I244d57a32f6066e5a5b9915f9fbf99e7bbca6e01 Signed-off-by: Yunhong Jiang <yunhong.jiang@linux.intel.com>
Diffstat (limited to 'kernel/mm/memcontrol.c')
-rw-r--r--kernel/mm/memcontrol.c239
1 files changed, 192 insertions, 47 deletions
diff --git a/kernel/mm/memcontrol.c b/kernel/mm/memcontrol.c
index 095d20f60..b5f5984aa 100644
--- a/kernel/mm/memcontrol.c
+++ b/kernel/mm/memcontrol.c
@@ -199,6 +199,7 @@ static void mem_cgroup_oom_notify(struct mem_cgroup *memcg);
/* "mc" and its members are protected by cgroup_mutex */
static struct move_charge_struct {
spinlock_t lock; /* for from, to */
+ struct mm_struct *mm;
struct mem_cgroup *from;
struct mem_cgroup *to;
unsigned long flags;
@@ -274,21 +275,7 @@ static inline bool mem_cgroup_is_root(struct mem_cgroup *memcg)
static inline unsigned short mem_cgroup_id(struct mem_cgroup *memcg)
{
- return memcg->css.id;
-}
-
-/*
- * A helper function to get mem_cgroup from ID. must be called under
- * rcu_read_lock(). The caller is responsible for calling
- * css_tryget_online() if the mem_cgroup is used for charging. (dropping
- * refcnt from swap can be called against removed memcg.)
- */
-static inline struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
-{
- struct cgroup_subsys_state *css;
-
- css = css_from_id(id, &memory_cgrp_subsys);
- return mem_cgroup_from_css(css);
+ return memcg->id.id;
}
/* Writing them here to avoid exposing memcg's inner layout */
@@ -1335,7 +1322,7 @@ static unsigned long mem_cgroup_get_limit(struct mem_cgroup *memcg)
return limit;
}
-static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
+static bool mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
int order)
{
struct oom_control oc = {
@@ -1413,6 +1400,7 @@ static void mem_cgroup_out_of_memory(struct mem_cgroup *memcg, gfp_t gfp_mask,
}
unlock:
mutex_unlock(&oom_lock);
+ return chosen;
}
#if MAX_NUMNODES > 1
@@ -2073,6 +2061,15 @@ retry:
current->flags & PF_EXITING))
goto force;
+ /*
+ * Prevent unbounded recursion when reclaim operations need to
+ * allocate memory. This might exceed the limits temporarily,
+ * but we prefer facilitating memory reclaim and getting back
+ * under the limit over triggering OOM kills in these cases.
+ */
+ if (unlikely(current->flags & PF_MEMALLOC))
+ goto force;
+
if (unlikely(task_in_memcg_oom(current)))
goto nomem;
@@ -3665,6 +3662,7 @@ static void memcg_deactivate_kmem(struct mem_cgroup *memcg)
* ordering is imposed by list_lru_node->lock taken by
* memcg_drain_all_list_lrus().
*/
+ rcu_read_lock(); /* can be called from css_free w/o cgroup_mutex */
css_for_each_descendant_pre(css, &memcg->css) {
child = mem_cgroup_from_css(css);
BUG_ON(child->kmemcg_id != kmemcg_id);
@@ -3672,6 +3670,8 @@ static void memcg_deactivate_kmem(struct mem_cgroup *memcg)
if (!memcg->use_hierarchy)
break;
}
+ rcu_read_unlock();
+
memcg_drain_all_list_lrus(kmemcg_id, parent->kmemcg_id);
memcg_free_cache_id(kmemcg_id);
@@ -4125,6 +4125,88 @@ static struct cftype mem_cgroup_legacy_files[] = {
{ }, /* terminate */
};
+/*
+ * Private memory cgroup IDR
+ *
+ * Swap-out records and page cache shadow entries need to store memcg
+ * references in constrained space, so we maintain an ID space that is
+ * limited to 16 bit (MEM_CGROUP_ID_MAX), limiting the total number of
+ * memory-controlled cgroups to 64k.
+ *
+ * However, there usually are many references to the oflline CSS after
+ * the cgroup has been destroyed, such as page cache or reclaimable
+ * slab objects, that don't need to hang on to the ID. We want to keep
+ * those dead CSS from occupying IDs, or we might quickly exhaust the
+ * relatively small ID space and prevent the creation of new cgroups
+ * even when there are much fewer than 64k cgroups - possibly none.
+ *
+ * Maintain a private 16-bit ID space for memcg, and allow the ID to
+ * be freed and recycled when it's no longer needed, which is usually
+ * when the CSS is offlined.
+ *
+ * The only exception to that are records of swapped out tmpfs/shmem
+ * pages that need to be attributed to live ancestors on swapin. But
+ * those references are manageable from userspace.
+ */
+
+static DEFINE_IDR(mem_cgroup_idr);
+
+static void mem_cgroup_id_get_many(struct mem_cgroup *memcg, unsigned int n)
+{
+ atomic_add(n, &memcg->id.ref);
+}
+
+static struct mem_cgroup *mem_cgroup_id_get_online(struct mem_cgroup *memcg)
+{
+ while (!atomic_inc_not_zero(&memcg->id.ref)) {
+ /*
+ * The root cgroup cannot be destroyed, so it's refcount must
+ * always be >= 1.
+ */
+ if (WARN_ON_ONCE(memcg == root_mem_cgroup)) {
+ VM_BUG_ON(1);
+ break;
+ }
+ memcg = parent_mem_cgroup(memcg);
+ if (!memcg)
+ memcg = root_mem_cgroup;
+ }
+ return memcg;
+}
+
+static void mem_cgroup_id_put_many(struct mem_cgroup *memcg, unsigned int n)
+{
+ if (atomic_sub_and_test(n, &memcg->id.ref)) {
+ idr_remove(&mem_cgroup_idr, memcg->id.id);
+ memcg->id.id = 0;
+
+ /* Memcg ID pins CSS */
+ css_put(&memcg->css);
+ }
+}
+
+static inline void mem_cgroup_id_get(struct mem_cgroup *memcg)
+{
+ mem_cgroup_id_get_many(memcg, 1);
+}
+
+static inline void mem_cgroup_id_put(struct mem_cgroup *memcg)
+{
+ mem_cgroup_id_put_many(memcg, 1);
+}
+
+/**
+ * mem_cgroup_from_id - look up a memcg from a memcg id
+ * @id: the memcg id to look up
+ *
+ * Caller must hold rcu_read_lock().
+ */
+struct mem_cgroup *mem_cgroup_from_id(unsigned short id)
+{
+ WARN_ON_ONCE(!rcu_read_lock_held());
+ return idr_find(&mem_cgroup_idr, id);
+}
+
static int alloc_mem_cgroup_per_zone_info(struct mem_cgroup *memcg, int node)
{
struct mem_cgroup_per_node *pn;
@@ -4179,6 +4261,12 @@ static struct mem_cgroup *mem_cgroup_alloc(void)
if (memcg_wb_domain_init(memcg, GFP_KERNEL))
goto out_free_stat;
+ memcg->id.id = idr_alloc(&mem_cgroup_idr, NULL,
+ 1, MEM_CGROUP_ID_MAX,
+ GFP_KERNEL);
+ if (memcg->id.id < 0)
+ goto out_free_stat;
+
return memcg;
out_free_stat:
@@ -4264,9 +4352,11 @@ mem_cgroup_css_alloc(struct cgroup_subsys_state *parent_css)
#ifdef CONFIG_CGROUP_WRITEBACK
INIT_LIST_HEAD(&memcg->cgwb_list);
#endif
+ idr_replace(&mem_cgroup_idr, memcg, memcg->id.id);
return &memcg->css;
free_out:
+ idr_remove(&mem_cgroup_idr, memcg->id.id);
__mem_cgroup_free(memcg);
return ERR_PTR(error);
}
@@ -4278,8 +4368,9 @@ mem_cgroup_css_online(struct cgroup_subsys_state *css)
struct mem_cgroup *parent = mem_cgroup_from_css(css->parent);
int ret;
- if (css->id > MEM_CGROUP_ID_MAX)
- return -ENOSPC;
+ /* Online state pins memcg ID, memcg ID pins CSS */
+ mem_cgroup_id_get(mem_cgroup_from_css(css));
+ css_get(css);
if (!parent)
return 0;
@@ -4353,6 +4444,8 @@ static void mem_cgroup_css_offline(struct cgroup_subsys_state *css)
memcg_deactivate_kmem(memcg);
wb_memcg_offline(memcg);
+
+ mem_cgroup_id_put(memcg);
}
static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
@@ -4409,9 +4502,9 @@ static int mem_cgroup_do_precharge(unsigned long count)
return ret;
}
- /* Try charges one by one with reclaim */
+ /* Try charges one by one with reclaim, but do not retry */
while (count--) {
- ret = try_charge(mc.to, GFP_KERNEL & ~__GFP_NORETRY, 1);
+ ret = try_charge(mc.to, GFP_KERNEL | __GFP_NORETRY, 1);
if (ret)
return ret;
mc.precharge++;
@@ -4786,6 +4879,8 @@ static void __mem_cgroup_clear_mc(void)
if (!mem_cgroup_is_root(mc.from))
page_counter_uncharge(&mc.from->memsw, mc.moved_swap);
+ mem_cgroup_id_put_many(mc.from, mc.moved_swap);
+
/*
* we charged both to->memory and to->memsw, so we
* should uncharge to->memory.
@@ -4793,9 +4888,9 @@ static void __mem_cgroup_clear_mc(void)
if (!mem_cgroup_is_root(mc.to))
page_counter_uncharge(&mc.to->memory, mc.moved_swap);
- css_put_many(&mc.from->css, mc.moved_swap);
+ mem_cgroup_id_get_many(mc.to, mc.moved_swap);
+ css_put_many(&mc.to->css, mc.moved_swap);
- /* we've already done css_get(mc.to) */
mc.moved_swap = 0;
}
memcg_oom_recover(from);
@@ -4805,6 +4900,8 @@ static void __mem_cgroup_clear_mc(void)
static void mem_cgroup_clear_mc(void)
{
+ struct mm_struct *mm = mc.mm;
+
/*
* we must clear moving_task before waking up waiters at the end of
* task migration.
@@ -4814,7 +4911,10 @@ static void mem_cgroup_clear_mc(void)
spin_lock(&mc.lock);
mc.from = NULL;
mc.to = NULL;
+ mc.mm = NULL;
spin_unlock(&mc.lock);
+
+ mmput(mm);
}
static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
@@ -4871,6 +4971,7 @@ static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
VM_BUG_ON(mc.moved_swap);
spin_lock(&mc.lock);
+ mc.mm = mm;
mc.from = from;
mc.to = memcg;
mc.flags = move_flags;
@@ -4880,8 +4981,9 @@ static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
ret = mem_cgroup_precharge_mc(mm);
if (ret)
mem_cgroup_clear_mc();
+ } else {
+ mmput(mm);
}
- mmput(mm);
return ret;
}
@@ -4990,11 +5092,11 @@ put: /* get_mctgt_type() gets the page */
return ret;
}
-static void mem_cgroup_move_charge(struct mm_struct *mm)
+static void mem_cgroup_move_charge(void)
{
struct mm_walk mem_cgroup_move_charge_walk = {
.pmd_entry = mem_cgroup_move_charge_pte_range,
- .mm = mm,
+ .mm = mc.mm,
};
lru_add_drain_all();
@@ -5006,7 +5108,7 @@ static void mem_cgroup_move_charge(struct mm_struct *mm)
atomic_inc(&mc.from->moving_account);
synchronize_rcu();
retry:
- if (unlikely(!down_read_trylock(&mm->mmap_sem))) {
+ if (unlikely(!down_read_trylock(&mc.mm->mmap_sem))) {
/*
* Someone who are holding the mmap_sem might be waiting in
* waitq. So we cancel all extra charges, wake up all waiters,
@@ -5023,23 +5125,16 @@ retry:
* additional charge, the page walk just aborts.
*/
walk_page_range(0, ~0UL, &mem_cgroup_move_charge_walk);
- up_read(&mm->mmap_sem);
+ up_read(&mc.mm->mmap_sem);
atomic_dec(&mc.from->moving_account);
}
-static void mem_cgroup_move_task(struct cgroup_taskset *tset)
+static void mem_cgroup_move_task(void)
{
- struct cgroup_subsys_state *css;
- struct task_struct *p = cgroup_taskset_first(tset, &css);
- struct mm_struct *mm = get_task_mm(p);
-
- if (mm) {
- if (mc.to)
- mem_cgroup_move_charge(mm);
- mmput(mm);
- }
- if (mc.to)
+ if (mc.to) {
+ mem_cgroup_move_charge();
mem_cgroup_clear_mc();
+ }
}
#else /* !CONFIG_MMU */
static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
@@ -5049,7 +5144,7 @@ static int mem_cgroup_can_attach(struct cgroup_taskset *tset)
static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
{
}
-static void mem_cgroup_move_task(struct cgroup_taskset *tset)
+static void mem_cgroup_move_task(void)
{
}
#endif
@@ -5127,6 +5222,7 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned long nr_pages;
unsigned long high;
int err;
@@ -5137,6 +5233,11 @@ static ssize_t memory_high_write(struct kernfs_open_file *of,
memcg->high = high;
+ nr_pages = page_counter_read(&memcg->memory);
+ if (nr_pages > high)
+ try_to_free_mem_cgroup_pages(memcg, nr_pages - high,
+ GFP_KERNEL, true);
+
memcg_wb_domain_size_changed(memcg);
return nbytes;
}
@@ -5158,6 +5259,8 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
char *buf, size_t nbytes, loff_t off)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(of_css(of));
+ unsigned int nr_reclaims = MEM_CGROUP_RECLAIM_RETRIES;
+ bool drained = false;
unsigned long max;
int err;
@@ -5166,9 +5269,36 @@ static ssize_t memory_max_write(struct kernfs_open_file *of,
if (err)
return err;
- err = mem_cgroup_resize_limit(memcg, max);
- if (err)
- return err;
+ xchg(&memcg->memory.limit, max);
+
+ for (;;) {
+ unsigned long nr_pages = page_counter_read(&memcg->memory);
+
+ if (nr_pages <= max)
+ break;
+
+ if (signal_pending(current)) {
+ err = -EINTR;
+ break;
+ }
+
+ if (!drained) {
+ drain_all_stock(memcg);
+ drained = true;
+ continue;
+ }
+
+ if (nr_reclaims) {
+ if (!try_to_free_mem_cgroup_pages(memcg, nr_pages - max,
+ GFP_KERNEL, true))
+ nr_reclaims--;
+ continue;
+ }
+
+ mem_cgroup_events(memcg, MEMCG_OOM, 1);
+ if (!mem_cgroup_out_of_memory(memcg, GFP_KERNEL, 0))
+ break;
+ }
memcg_wb_domain_size_changed(memcg);
return nbytes;
@@ -5228,7 +5358,7 @@ struct cgroup_subsys memory_cgrp_subsys = {
.css_reset = mem_cgroup_css_reset,
.can_attach = mem_cgroup_can_attach,
.cancel_attach = mem_cgroup_cancel_attach,
- .attach = mem_cgroup_move_task,
+ .post_attach = mem_cgroup_move_task,
.bind = mem_cgroup_bind,
.dfl_cftypes = memory_files,
.legacy_cftypes = mem_cgroup_legacy_files,
@@ -5636,7 +5766,7 @@ subsys_initcall(mem_cgroup_init);
*/
void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
{
- struct mem_cgroup *memcg;
+ struct mem_cgroup *memcg, *swap_memcg;
unsigned short oldid;
unsigned long flags;
@@ -5652,15 +5782,27 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
if (!memcg)
return;
- oldid = swap_cgroup_record(entry, mem_cgroup_id(memcg));
+ /*
+ * In case the memcg owning these pages has been offlined and doesn't
+ * have an ID allocated to it anymore, charge the closest online
+ * ancestor for the swap instead and transfer the memory+swap charge.
+ */
+ swap_memcg = mem_cgroup_id_get_online(memcg);
+ oldid = swap_cgroup_record(entry, mem_cgroup_id(swap_memcg));
VM_BUG_ON_PAGE(oldid, page);
- mem_cgroup_swap_statistics(memcg, true);
+ mem_cgroup_swap_statistics(swap_memcg, true);
page->mem_cgroup = NULL;
if (!mem_cgroup_is_root(memcg))
page_counter_uncharge(&memcg->memory, 1);
+ if (memcg != swap_memcg) {
+ if (!mem_cgroup_is_root(swap_memcg))
+ page_counter_charge(&swap_memcg->memsw, 1);
+ page_counter_uncharge(&memcg->memsw, 1);
+ }
+
/*
* Interrupts should be disabled here because the caller holds the
* mapping->tree_lock lock which is taken with interrupts-off. It is
@@ -5673,6 +5815,9 @@ void mem_cgroup_swapout(struct page *page, swp_entry_t entry)
#endif
mem_cgroup_charge_statistics(memcg, page, -1);
memcg_check_events(memcg, page);
+
+ if (!mem_cgroup_is_root(memcg))
+ css_put(&memcg->css);
local_unlock_irqrestore(event_lock, flags);
}
@@ -5697,7 +5842,7 @@ void mem_cgroup_uncharge_swap(swp_entry_t entry)
if (!mem_cgroup_is_root(memcg))
page_counter_uncharge(&memcg->memsw, 1);
mem_cgroup_swap_statistics(memcg, false);
- css_put(&memcg->css);
+ mem_cgroup_id_put(memcg);
}
rcu_read_unlock();
}