Re: [PATCH] slab+slob: dup name string

On 05/22/2012 07:22 AM, David Rientjes wrote:

quoted

-	if (setup_cpu_cache(cachep, gfp)) {

quoted

 +	/* Can't do strdup while kmalloc is not up */
 +	if (g_cpucache_up>  EARLY)
 +		cachep->name = kstrdup(name, GFP_KERNEL);
 +	else
 +		cachep->name = name;
 +
 +	if (!cachep->name || setup_cpu_cache(cachep, gfp)) {
   		__kmem_cache_destroy(cachep);
   		cachep = NULL;
   		goto oops;

This doesn't work if you kmem_cache_destroy() a cache that was created
when g_cpucache_cpu<= EARLY, the kfree() will explode.  That never
happens for any existing cache created in kmem_cache_init(), but this
would introduce the first roadblock in doing so.  So you'll need some
magic to determine whether the cache was allocated statically and suppress
the kfree() in such a case.

David,

I tried to do something like I was doing for the memcg caches: after creation of the kmalloc + cache_cache, I loop through them and duplicate the name. So instead of conditionally freeing the late caches - that could cause consistency headaches in the future - kfree'ing the name string will just work for all of them. I will send it shortly.

Cristoph, I am dropping your ack since this change is quite significant. If you agree with it, would you ack it again?

Thanks.

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