On Mon, 23 Mar 2020 17:42:21 -0700 Roman Gushchin <guro@xxxxxx> wrote:
> How about this one? I've merged them into one and stripped it a little bit.
>
> Thanks!
>
Yes, that looks good. Here's the delta from the previously reviewed
version. I think it's valid to retain those acks and revewed-by's.
From: Roman Gushchin <guro@xxxxxx>
Subject: mm: fork: fix kernel_stack memcg stats for various stack implementations
--- a/include/linux/memcontrol.h~mm-fork-fix-kernel_stack-memcg-stats-for-various-stack-implementations-v2
+++ a/include/linux/memcontrol.h
@@ -1432,6 +1432,8 @@ static inline int memcg_cache_id(struct
return memcg ? memcg->kmemcg_id : -1;
}
+struct mem_cgroup *mem_cgroup_from_obj(void *p);
+
#else
static inline int memcg_kmem_charge(struct page *page, gfp_t gfp, int order)
@@ -1473,6 +1475,11 @@ static inline void memcg_put_cache_ids(v
{
}
+static inline struct mem_cgroup *mem_cgroup_from_obj(void *p)
+{
+ return NULL;
+}
+
#endif /* CONFIG_MEMCG_KMEM */
#endif /* _LINUX_MEMCONTROL_H */
--- a/mm/memcontrol.c~mm-fork-fix-kernel_stack-memcg-stats-for-various-stack-implementations-v2
+++ a/mm/memcontrol.c
@@ -2672,6 +2672,33 @@ static void commit_charge(struct page *p
}
#ifdef CONFIG_MEMCG_KMEM
+/*
+ * Returns a pointer to the memory cgroup to which the kernel object is charged.
+ *
+ * The caller must ensure the memcg lifetime, e.g. by taking rcu_read_lock(),
+ * cgroup_mutex, etc.
+ */
+struct mem_cgroup *mem_cgroup_from_obj(void *p)
+{
+ struct page *page;
+
+ if (mem_cgroup_disabled())
+ return NULL;
+
+ page = virt_to_head_page(p);
+
+ /*
+ * Slab pages don't have page->mem_cgroup set because corresponding
+ * kmem caches can be reparented during the lifetime. That's why
+ * memcg_from_slab_page() should be used instead.
+ */
+ if (PageSlab(page))
+ return memcg_from_slab_page(page);
+
+ /* All other pages use page->mem_cgroup */
+ return page->mem_cgroup;
+}
+
static int memcg_alloc_cache_id(void)
{
int id, size;
_
