/* "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;
if (prev && reclaim->generation != iter->generation)
goto out_unlock;
- do {
+ while (1) {
pos = READ_ONCE(iter->position);
+ if (!pos || css_tryget(&pos->css))
+ break;
/*
- * A racing update may change the position and
- * put the last reference, hence css_tryget(),
- * or retry to see the updated position.
+ * css reference reached zero, so iter->position will
+ * be cleared by ->css_released. However, we should not
+ * rely on this happening soon, because ->css_released
+ * is called from a work queue, and by busy-waiting we
+ * might block it. So we clear iter->position right
+ * away.
*/
- } while (pos && !css_tryget(&pos->css));
+ (void)cmpxchg(&iter->position, pos, NULL);
+ }
}
if (pos)
}
if (reclaim) {
- if (cmpxchg(&iter->position, pos, memcg) == pos) {
- if (memcg)
- css_get(&memcg->css);
- if (pos)
- css_put(&pos->css);
- }
-
/*
- * pairs with css_tryget when dereferencing iter->position
- * above.
+ * The position could have already been updated by a competing
+ * thread, so check that the value hasn't changed since we read
+ * it to avoid reclaiming from the same cgroup twice.
*/
+ (void)cmpxchg(&iter->position, pos, memcg);
+
if (pos)
css_put(&pos->css);
css_put(&prev->css);
}
+static void invalidate_reclaim_iterators(struct mem_cgroup *dead_memcg)
+{
+ struct mem_cgroup *memcg = dead_memcg;
+ struct mem_cgroup_reclaim_iter *iter;
+ struct mem_cgroup_per_zone *mz;
+ int nid, zid;
+ int i;
+
+ while ((memcg = parent_mem_cgroup(memcg))) {
+ for_each_node(nid) {
+ for (zid = 0; zid < MAX_NR_ZONES; zid++) {
+ mz = &memcg->nodeinfo[nid]->zoneinfo[zid];
+ for (i = 0; i <= DEF_PRIORITY; i++) {
+ iter = &mz->iter[i];
+ cmpxchg(&iter->position,
+ dead_memcg, NULL);
+ }
+ }
+ }
+ }
+}
+
/*
* Iteration constructs for visiting all cgroups (under a tree). If
* loops are exited prematurely (break), mem_cgroup_iter_break() must
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 = {
}
unlock:
mutex_unlock(&oom_lock);
+ return chosen;
}
#if MAX_NUMNODES > 1
swap_buffers:
/* Swap primary and spare array */
thresholds->spare = thresholds->primary;
- /* If all events are unregistered, free the spare array */
- if (!new) {
- kfree(thresholds->spare);
- thresholds->spare = NULL;
- }
rcu_assign_pointer(thresholds->primary, new);
/* To be sure that nobody uses thresholds */
synchronize_rcu();
+
+ /* If all events are unregistered, free the spare array */
+ if (!new) {
+ kfree(thresholds->spare);
+ thresholds->spare = NULL;
+ }
unlock:
mutex_unlock(&memcg->thresholds_lock);
}
wb_memcg_offline(memcg);
}
+static void mem_cgroup_css_released(struct cgroup_subsys_state *css)
+{
+ struct mem_cgroup *memcg = mem_cgroup_from_css(css);
+
+ invalidate_reclaim_iterators(memcg);
+}
+
static void mem_cgroup_css_free(struct cgroup_subsys_state *css)
{
struct mem_cgroup *memcg = mem_cgroup_from_css(css);
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.
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)
VM_BUG_ON(mc.moved_swap);
spin_lock(&mc.lock);
+ mc.mm = mm;
mc.from = from;
mc.to = memcg;
mc.flags = move_flags;
ret = mem_cgroup_precharge_mc(mm);
if (ret)
mem_cgroup_clear_mc();
+ } else {
+ mmput(mm);
}
- mmput(mm);
return ret;
}
+static int mem_cgroup_allow_attach(struct cgroup_taskset *tset)
+{
+ return subsys_cgroup_allow_attach(tset);
+}
+
static void mem_cgroup_cancel_attach(struct cgroup_taskset *tset)
{
if (mc.to)
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();
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,
* 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)
{
return 0;
}
+static int mem_cgroup_allow_attach(struct cgroup_taskset *tset)
+{
+ return 0;
+}
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
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;
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;
}
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;
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;
.css_alloc = mem_cgroup_css_alloc,
.css_online = mem_cgroup_css_online,
.css_offline = mem_cgroup_css_offline,
+ .css_released = mem_cgroup_css_released,
.css_free = mem_cgroup_css_free,
.css_reset = mem_cgroup_css_reset,
.can_attach = mem_cgroup_can_attach,
.cancel_attach = mem_cgroup_cancel_attach,
.attach = mem_cgroup_move_task,
+ .allow_attach = mem_cgroup_allow_attach,
+ .post_attach = mem_cgroup_move_task,
.bind = mem_cgroup_bind,
.dfl_cftypes = memory_files,
.legacy_cftypes = mem_cgroup_legacy_files,
projects / firefly-linux-kernel-4.4.55.git / blobdiff