slab/slub: struct memcg_params

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: David Rientjes <rientjes@google.com>
Cc: Frederic Weisbecker <fweisbec@redhat.com>
Cc: Greg Thelen <gthelen@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: JoonSoo Kim <js1304@gmail.com>
Cc: KAMEZAWA Hiroyuki <kamezawa.hiroyu@jp.fujitsu.com>
Cc: Mel Gorman <mel@csn.ul.ie>
Cc: Michal Hocko <mhocko@suse.cz>
Cc: Pekka Enberg <penberg@cs.helsinki.fi>
Cc: Rik van Riel <riel@redhat.com>
Cc: Tejun Heo <tj@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>

diff --git a/include/linux/slab.h b/include/linux/slab.h
index 743a104151229e0efc5416cf7a54383d3ba41c82..00efba1492220f49d9dfbdc8abdea417776b0367 100644 (file)
--- a/include/linux/slab.h
+++ b/include/linux/slab.h
@@ -176,6 +176,30 @@ void kmem_cache_free(struct kmem_cache *, void *);
 #define ARCH_SLAB_MINALIGN __alignof__(unsigned long long)
 #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
  */

diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
index cc290f0bdb346efe82dbe0e87985e6d015ad58e1..b07cc4c118404910e2a0e342ea08428bd2440c2c 100644 (file)
--- 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 df448adb7283fa534edf23656b1c90b6e27982b0..961e72eab907b38317d31c7e3e00cae18d087b28 100644 (file)
--- 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 66a62d3536c622b8386c15b5d1e2e9e7fac6dbd7..5ee1851f5834243e9a759473d6613b135155024f 100644 (file)
--- 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