Now memcg has the same life cycle as its corresponding cgroup,
we don't have to save the cgroup path name in memcg->memcg_name.
Signed-off-by: Li Zefan <lizefan@xxxxxxxxxx>
---
mm/memcontrol.c | 65 +++++++++++++++++++++------------------------------------
1 file changed, 24 insertions(+), 41 deletions(-)
diff --git a/mm/memcontrol.c b/mm/memcontrol.c
index aeab1d3..06e995e 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -306,20 +306,12 @@ struct mem_cgroup {
struct list_head dead;
};
- union {
- /*
- * 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;
+ /*
+ * 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;
- /*
- * We are no longer concerned about moving charges after memcg
- * is dead. So we will fill this up with its name, to aid
- * debugging.
- */
- char *memcg_name;
- };
/*
* set > 0 if pages under this cgroup are moving to other cgroup.
*/
@@ -381,36 +373,10 @@ static inline void memcg_dangling_free(struct mem_cgroup *memcg)
mutex_lock(&dangling_memcgs_mutex);
list_del(&memcg->dead);
mutex_unlock(&dangling_memcgs_mutex);
- free_pages((unsigned long)memcg->memcg_name, 0);
}
static inline void memcg_dangling_add(struct mem_cgroup *memcg)
{
- /*
- * cgroup.c will do page-sized allocations most of the time,
- * so we'll just follow the pattern. Also, __get_free_pages
- * is a better interface than kmalloc for us here, because
- * we'd like this memory to be always billed to the root cgroup,
- * not to the process removing the memcg. While kmalloc would
- * require us to wrap it into memcg_stop/resume_kmem_account,
- * with __get_free_pages we just don't pass the memcg flag.
- */
- memcg->memcg_name = (char *)__get_free_pages(GFP_KERNEL, 0);
-
- /*
- * we will, in general, just ignore failures. No need to go crazy,
- * being this just a debugging interface. It is nice to copy a memcg
- * name over, but if we (unlikely) can't, just the address will do
- */
- if (!memcg->memcg_name)
- goto add_list;
-
- if (cgroup_path(memcg->css.cgroup, memcg->memcg_name, PAGE_SIZE) < 0) {
- free_pages((unsigned long)memcg->memcg_name, 0);
- memcg->memcg_name = NULL;
- }
-
-add_list:
INIT_LIST_HEAD(&memcg->dead);
mutex_lock(&dangling_memcgs_mutex);
list_add(&memcg->dead, &dangling_memcgs);
@@ -5188,12 +5154,28 @@ static int mem_cgroup_dangling_read(struct cgroup *cont, struct cftype *cft,
struct seq_file *m)
{
struct mem_cgroup *memcg;
+ char *memcg_name;
+ int ret;
+
+ /*
+ * cgroup.c will do page-sized allocations most of the time,
+ * so we'll just follow the pattern. Also, __get_free_pages
+ * is a better interface than kmalloc for us here, because
+ * we'd like this memory to be always billed to the root cgroup,
+ * not to the process removing the memcg. While kmalloc would
+ * require us to wrap it into memcg_stop/resume_kmem_account,
+ * with __get_free_pages we just don't pass the memcg flag.
+ */
+ memcg_name = (char *)__get_free_pages(GFP_KERNEL, 0);
+ if (!memcg_name)
+ return -ENOMEM;
mutex_lock(&dangling_memcgs_mutex);
list_for_each_entry(memcg, &dangling_memcgs, dead) {
- if (memcg->memcg_name)
- seq_printf(m, "%s:\n", memcg->memcg_name);
+ ret = cgroup_path(memcg->css.cgroup, memcg_name, PAGE_SIZE);
+ if (!ret)
+ seq_printf(m, "%s:\n", memcg_name);
else
seq_printf(m, "%p (name lost):\n", memcg);
@@ -5203,6 +5185,7 @@ static int mem_cgroup_dangling_read(struct cgroup *cont, struct cftype *cft,
}
mutex_unlock(&dangling_memcgs_mutex);
+ free_pages((unsigned long)memcg_name, 0);
return 0;
}
#endif
--
1.8.0.2
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