On Fri, Oct 16, 2015 at 03:12:23PM -0700, Hugh Dickins wrote:
...
> Are you expecting to use mem_cgroup_from_kmem() from other places
> in future?  Seems possible; but at present it's called from only

Not in the near future. At least, currently I can't think of any other
use for it except list_lru_from_kmem.

> one place, and (given how memcontrol.h has somehow managed to avoid
> including mm.h all these years), I thought it would be nice to avoid
> it for just this; and fixed my build with the patch below last night.
> Whatever you all think best: just wanted to point out an alternative.

Makes sense, thanks!

I would even inline mem_cgroup_from_kmem to list_lru_from_kmem:

diff --git a/include/linux/memcontrol.h b/include/linux/memcontrol.h
index 47677acb4516..2077b9bb4883 100644
--- a/include/linux/memcontrol.h
+++ b/include/linux/memcontrol.h
@@ -831,16 +831,6 @@ static __always_inline void memcg_kmem_put_cache(struct 
kmem_cache *cachep)
        if (memcg_kmem_enabled())
                __memcg_kmem_put_cache(cachep);
 }
-
-static __always_inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
-{
-       struct page *page;
-
-       if (!memcg_kmem_enabled())
-               return NULL;
-       page = virt_to_head_page(ptr);
-       return page->mem_cgroup;
-}
 #else
 #define for_each_memcg_cache_index(_idx)       \
        for (; NULL; )
@@ -886,11 +876,6 @@ memcg_kmem_get_cache(struct kmem_cache *cachep, gfp_t gfp)
 static inline void memcg_kmem_put_cache(struct kmem_cache *cachep)
 {
 }
-
-static inline struct mem_cgroup *mem_cgroup_from_kmem(void *ptr)
-{
-       return NULL;
-}
 #endif /* CONFIG_MEMCG_KMEM */
 #endif /* _LINUX_MEMCONTROL_H */
 
diff --git a/mm/list_lru.c b/mm/list_lru.c
index 28237476b055..00d0a70af70a 100644
--- a/mm/list_lru.c
+++ b/mm/list_lru.c
@@ -68,10 +68,10 @@ list_lru_from_kmem(struct list_lru_node *nlru, void *ptr)
 {
        struct mem_cgroup *memcg;
 
-       if (!nlru->memcg_lrus)
+       if (!memcg_kmem_enabled() || !nlru->memcg_lrus)
                return &nlru->lru;
 
-       memcg = mem_cgroup_from_kmem(ptr);
+       memcg = virt_to_head_page(ptr)->mem_cgroup;
        if (!memcg)
                return &nlru->lru;
 
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majord...@vger.kernel.org
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/

Reply via email to