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-rw-r--r--mm/memcontrol.c97
1 files changed, 93 insertions, 4 deletions
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index d813823..59ffaf5 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -226,11 +226,26 @@ struct mem_cgroup {
bool memsw_is_minimum;
/*
+ * Should we move charges of a task when a task is moved into this
+ * mem_cgroup ? And what type of charges should we move ?
+ */
+ unsigned long move_charge_at_immigrate;
+
+ /*
* statistics. This must be placed at the end of memcg.
*/
struct mem_cgroup_stat stat;
};
+/* Stuffs for move charges at task migration. */
+/*
+ * Types of charges to be moved. "move_charge_at_immitgrate" is treated as a
+ * left-shifted bitmap of these types.
+ */
+enum move_type {
+ NR_MOVE_TYPE,
+};
+
/*
* Maximum loops in mem_cgroup_hierarchical_reclaim(), used for soft
* limit reclaim to prevent infinite loops, if they ever occur.
@@ -2865,6 +2880,31 @@ static int mem_cgroup_reset(struct cgroup *cont, unsigned int event)
return 0;
}
+static u64 mem_cgroup_move_charge_read(struct cgroup *cgrp,
+ struct cftype *cft)
+{
+ return mem_cgroup_from_cont(cgrp)->move_charge_at_immigrate;
+}
+
+static int mem_cgroup_move_charge_write(struct cgroup *cgrp,
+ struct cftype *cft, u64 val)
+{
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgrp);
+
+ if (val >= (1 << NR_MOVE_TYPE))
+ return -EINVAL;
+ /*
+ * We check this value several times in both in can_attach() and
+ * attach(), so we need cgroup lock to prevent this value from being
+ * inconsistent.
+ */
+ cgroup_lock();
+ mem->move_charge_at_immigrate = val;
+ cgroup_unlock();
+
+ return 0;
+}
+
/* For read statistics */
enum {
@@ -3098,6 +3138,11 @@ static struct cftype mem_cgroup_files[] = {
.read_u64 = mem_cgroup_swappiness_read,
.write_u64 = mem_cgroup_swappiness_write,
},
+ {
+ .name = "move_charge_at_immigrate",
+ .read_u64 = mem_cgroup_move_charge_read,
+ .write_u64 = mem_cgroup_move_charge_write,
+ },
};
#ifdef CONFIG_CGROUP_MEM_RES_CTLR_SWAP
@@ -3345,6 +3390,7 @@ mem_cgroup_create(struct cgroup_subsys *ss, struct cgroup *cont)
if (parent)
mem->swappiness = get_swappiness(parent);
atomic_set(&mem->refcnt, 1);
+ mem->move_charge_at_immigrate = 0;
return &mem->css;
free_out:
__mem_cgroup_free(mem);
@@ -3381,16 +3427,57 @@ static int mem_cgroup_populate(struct cgroup_subsys *ss,
return ret;
}
+/* Handlers for move charge at task migration. */
+static int mem_cgroup_can_move_charge(void)
+{
+ return 0;
+}
+
+static int mem_cgroup_can_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p,
+ bool threadgroup)
+{
+ int ret = 0;
+ struct mem_cgroup *mem = mem_cgroup_from_cont(cgroup);
+
+ if (mem->move_charge_at_immigrate) {
+ struct mm_struct *mm;
+ struct mem_cgroup *from = mem_cgroup_from_task(p);
+
+ VM_BUG_ON(from == mem);
+
+ mm = get_task_mm(p);
+ if (!mm)
+ return 0;
+
+ /* We move charges only when we move a owner of the mm */
+ if (mm->owner == p)
+ ret = mem_cgroup_can_move_charge();
+
+ mmput(mm);
+ }
+ return ret;
+}
+
+static void mem_cgroup_cancel_attach(struct cgroup_subsys *ss,
+ struct cgroup *cgroup,
+ struct task_struct *p,
+ bool threadgroup)
+{
+}
+
+static void mem_cgroup_move_charge(void)
+{
+}
+
static void mem_cgroup_move_task(struct cgroup_subsys *ss,
struct cgroup *cont,
struct cgroup *old_cont,
struct task_struct *p,
bool threadgroup)
{
- /*
- * FIXME: It's better to move charges of this process from old
- * memcg to new memcg. But it's just on TODO-List now.
- */
+ mem_cgroup_move_charge();
}
struct cgroup_subsys mem_cgroup_subsys = {
@@ -3400,6 +3487,8 @@ struct cgroup_subsys mem_cgroup_subsys = {
.pre_destroy = mem_cgroup_pre_destroy,
.destroy = mem_cgroup_destroy,
.populate = mem_cgroup_populate,
+ .can_attach = mem_cgroup_can_attach,
+ .cancel_attach = mem_cgroup_cancel_attach,
.attach = mem_cgroup_move_task,
.early_init = 0,
.use_id = 1,
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