[PATCH v6 15/29] slab/slub: struct memcg_params

Glauber Costa
2012-11-01T12:13:00Z

For the kmem slab controller, we need to record some extra
information in the kmem_cache structure.

Signed-off-by: Glauber Costa <glommer@parallels.com>
Signed-off-by: Suleiman Souhlal <suleiman@google.com>
CC: Christoph Lameter <cl@linux.com>
CC: Pekka Enberg <penberg@cs.helsinki.fi>
CC: Michal Hocko <mhocko@suse.cz>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
CC: Johannes Weiner <hannes@cmpxchg.org>
CC: Tejun Heo <tj@kernel.org>
---
include/linux/slab.h | 24 ++++++++++++++++++++++++
include/linux/slab_def.h | 3 +++
include/linux/slub_def.h | 3 +++
mm/slab.h | 13 +++++++++++++
4 files changed, 43 insertions(+)

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 0dd2dfa..8860e08 100644
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -178,6 +178,30 @@ unsigned int kmem_cache_size(struct kmem_cache *);
#endif

/*
+ * This is the main placeholder for memcg-related information in kmem caches.
+ * struct kmem_cache will hold a pointer to it, so the memory cost while
+ * disabled is 1 pointer. The runtime cost while enabled, gets bigger than it
+ * would otherwise be if that would be bundled in kmem_cache: we'll need an
+ * extra pointer chase. But the trade off clearly lays in favor of not
+ * penalizing non-users.
+ *
+ * Both the root cache and the child caches will have it. For the root cache,
+ * this will hold a dynamically allocated array large enough to hold
+ * information about the currently limited memcgs in the system.
+ *
+ * Child caches will hold extra metadata needed for its operation. Fields are:
+ *
+ * @memcg: pointer to the memcg this cache belongs to
+ */
+struct memcg_cache_params {
+ bool is_root_cache;
+ union {
+ struct kmem_cache *memcg_caches[0];
+ struct mem_cgroup *memcg;
+ };
+};
+
+/*
* Common kmalloc functions provided by all allocators
*/
void * __must_check __krealloc(const void *, size_t, gfp_t);
diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index 36d7031..665afa4 100644
--- a/include/linux/slab_def.h
+++ b/include/linux/slab_def.h
@@ -81,6 +81,9 @@ struct kmem_cache {
*/
int obj_offset;
#endif /* CONFIG_DEBUG_SLAB */
+#ifdef CONFIG_MEMCG_KMEM
+ struct memcg_cache_params *memcg_params;
+#endif

/* 6) per-cpu/per-node data, touched during every alloc/free */
/*
diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
index df448ad..961e72e 100644
--- a/include/linux/slub_def.h
+++ b/include/linux/slub_def.h
@@ -101,6 +101,9 @@ struct kmem_cache {
#ifdef CONFIG_SYSFS
struct kobject kobj; /* For sysfs */
#endif
+#ifdef CONFIG_MEMCG_KMEM
+ struct memcg_cache_params *memcg_params;
+#endif

#ifdef CONFIG_NUMA
/*
diff --git a/mm/slab.h b/mm/slab.h
index 66a62d3..5ee1851 100644
--- a/mm/slab.h
+++ b/mm/slab.h
@@ -92,4 +92,17 @@ void get_slabinfo(struct kmem_cache *s, struct slabinfo *sinfo);
void slabinfo_show_stats(struct seq_file *m, struct kmem_cache *s);
ssize_t slabinfo_write(struct file *file, const char __user *buffer,
size_t count, loff_t *ppos);
+
+#ifdef CONFIG_MEMCG_KMEM
+static inline bool is_root_cache(struct kmem_cache *s)
+{
+ return !s->memcg_params || s->memcg_params->is_root_cache;
+}
+#else
+static inline bool is_root_cache(struct kmem_cache *s)
+{
+ return true;
+}
+
+#endif
#endif
--
1.7.11.7