On 05/29/2012 06:36 PM, Christoph Lameter wrote:
On Fri, 25 May 2012, Glauber Costa wrote:
index dacd1fb..4689034 100644
--- a/mm/memcontrol.c
+++ b/mm/memcontrol.c
@@ -467,6 +467,23 @@ struct cg_proto *tcp_proto_cgroup(struct mem_cgroup *memcg)
EXPORT_SYMBOL(tcp_proto_cgroup);
#endif /* CONFIG_INET */
+char *mem_cgroup_cache_name(struct mem_cgroup *memcg, struct kmem_cache *cachep)
+{
+ char *name;
+ struct dentry *dentry;
+
+ rcu_read_lock();
+ dentry = rcu_dereference(memcg->css.cgroup->dentry);
+ rcu_read_unlock();
+
+ BUG_ON(dentry == NULL);
+
+ name = kasprintf(GFP_KERNEL, "%s(%d:%s)",
+ cachep->name, css_id(&memcg->css), dentry->d_name.name);
+
+ return name;
+}
Function allocates a string that is supposed to be disposed of by the
caller. That needs to be documented and maybe even the name needs to
reflect that.
Okay, I can change it.
--- a/mm/slub.c
+++ b/mm/slub.c
@@ -4002,6 +4002,38 @@ struct kmem_cache *kmem_cache_create(const char *name, size_t size,
}
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 *s)
+{
+ char *name;
+ struct kmem_cache *new;
+
+ name = mem_cgroup_cache_name(memcg, s);
+ if (!name)
+ return NULL;
+
+ new = kmem_cache_create_memcg(memcg, name, s->objsize, s->align,
+ (s->allocflags& ~SLAB_PANIC), s->ctor);
Hmmm... A full duplicate of the slab cache? We may have many sparsely
used portions of the per node and per cpu structure as a result.
I've already commented on patch 0, but I will repeat it here. This
approach leads to more fragmentation, yes, but this is exactly to be
less intrusive.
With a full copy, all I need to do is:
1) relay the allocation to the right cache.
2) account for a new page when it is needed.
How does the cache work from inside? I don't care.
Accounting pages seems just crazy to me. If new allocators come in the
future, organizing the pages in a different way, instead of patching it
here and there, we need to totally rewrite this.
If those allocators happen to depend on a specific placement for
performance, then we're destroying this as well too.
+ * prevent it from being deleted. If kmem_cache_destroy() is
+ * called for the root cache before we call it for a child cache,
+ * it will be queued for destruction when we finally drop the
+ * reference on the child cache.
+ */
+ if (new) {
+ down_write(&slub_lock);
+ s->refcount++;
+ up_write(&slub_lock);
+ }
Why do you need to increase the refcount? You made a full copy right?
Yes, but I don't want this copy to go away while we have other caches
around.
So, in the memcg internals, I used a different reference counter, to
avoid messing with this one. I could use that, and leave the original
refcnt alone. Would you prefer this?
--
To unsubscribe, send a message with 'unsubscribe linux-mm' in
the body to majordomo@xxxxxxxxx. For more info on Linux MM,
see: http://www.linux-mm.org/ .
Fight unfair telecom internet charges in Canada: sign http://stopthemeter.ca/
Don't email: <a href=mailto:"dont@xxxxxxxxx";> email@xxxxxxxxx </a>