This patch provides kmem_cache_dup(), that duplicates
a cache for a memcg, preserving its creation properties.
Object size, alignment and flags are all respected.
An exception is the SLAB_PANIC flag, since cache creation
inside a memcg should not be fatal.
This code is mostly written by Suleiman Souhlal,
with some adaptations and simplifications by me.
[ v3: add get_online cpus before the slab mutex ]
Signed-off-by: Glauber Costa <glommer@xxxxxxxxxxxxx>
Signed-off-by: Suleiman Souhlal <suleiman@xxxxxxxxxx>
CC: Christoph Lameter <cl@xxxxxxxxx>
CC: Pekka Enberg <penberg@xxxxxxxxxxxxxx>
CC: Michal Hocko <mhocko@xxxxxxx>
CC: Kamezawa Hiroyuki <kamezawa.hiroyu@xxxxxxxxxxxxxx>
CC: Johannes Weiner <hannes@xxxxxxxxxxx>
---
mm/slab.c | 44 ++++++++++++++++++++++++++++++++++++++++++++
1 files changed, 44 insertions(+), 0 deletions(-)
diff --git a/mm/slab.c b/mm/slab.c
index 8bff32a1..e2227de 100644
--- a/mm/slab.c
+++ b/mm/slab.c
@@ -301,6 +301,8 @@ static void free_block(struct kmem_cache *cachep, void **objpp, int len,
int node);
static int enable_cpucache(struct kmem_cache *cachep, gfp_t gfp);
static void cache_reap(struct work_struct *unused);
+static int do_tune_cpucache(struct kmem_cache *cachep, int limit,
+ int batchcount, int shared, gfp_t gfp);
/*
* This function must be completely optimized away if a constant is passed to
@@ -2616,6 +2618,42 @@ kmem_cache_create(const char *name, size_t size, size_t align,
}
EXPORT_SYMBOL(kmem_cache_create);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+struct kmem_cache *kmem_cache_dup(struct mem_cgroup *memcg,
+ struct kmem_cache *cachep)
+{
+ struct kmem_cache *new;
+ unsigned long flags;
+ char *name;
+
+ name = mem_cgroup_cache_name(memcg, cachep);
+ if (!name)
+ return NULL;
+
+ flags = cachep->flags & ~(SLAB_PANIC|CFLGS_OFF_SLAB);
+
+ get_online_cpus();
+ mutex_lock(&cache_chain_mutex);
+ new = __kmem_cache_create(memcg, name, obj_size(cachep),
+ cachep->memcg_params.orig_align, flags, cachep->ctor);
+
+ if (new == NULL) {
+ kfree(name);
+ goto out;
+ }
+
+ if ((cachep->limit != new->limit) ||
+ (cachep->batchcount != new->batchcount) ||
+ (cachep->shared != new->shared))
+ do_tune_cpucache(new, cachep->limit, cachep->batchcount,
+ cachep->shared, GFP_KERNEL);
+out:
+ mutex_unlock(&cache_chain_mutex);
+ put_online_cpus();
+ return new;
+}
+#endif /* CONFIG_CGROUP_MEM_RES_CTLR_KMEM */
+
#if DEBUG
static void check_irq_off(void)
{
@@ -2811,6 +2849,12 @@ void kmem_cache_destroy(struct kmem_cache *cachep)
rcu_barrier();
mem_cgroup_release_cache(cachep);
+#ifdef CONFIG_CGROUP_MEM_RES_CTLR_KMEM
+ /* memcg cache: free the name string. Doing it here saves us
+ * a pointer to it outside the slab code */
+ if (cachep->memcg_params.id == -1)
+ kfree(cachep->name);
+#endif
__kmem_cache_destroy(cachep);
mutex_unlock(&cache_chain_mutex);
--
1.7.7.6
--
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