On Tue, 10 Apr 2018, Matthew Wilcox wrote:
> diff --git a/mm/slab.h b/mm/slab.h
> index 3cd4677953c6..896818c7b30a 100644
> --- a/mm/slab.h
> +++ b/mm/slab.h
> @@ -515,6 +515,13 @@ static inline void dump_unreclaimable_slab(void)
>
> void ___cache_free(struct kmem_cache *cache, void *x, unsigned long addr);
>
> +static inline bool slab_no_ctor(struct kmem_cache *s)
> +{
> + if (IS_ENABLED(CONFIG_DEBUG_VM))
> + return !WARN_ON_ONCE(s->ctor);
> + return true;
> +}
> +
> #ifdef CONFIG_SLAB_FREELIST_RANDOM
> int cache_random_seq_create(struct kmem_cache *cachep, unsigned int count,
> gfp_t gfp);
Move that to mm/slab.c? Debugging is runtime enabled with SLUB not compile
time as with SLAB.
> +++ b/mm/slub.c
> @@ -2725,7 +2726,7 @@ static __always_inline void *slab_alloc_node(struct kmem_cache *s,
> stat(s, ALLOC_FASTPATH);
> }
>
> - if (unlikely(gfpflags & __GFP_ZERO) && object)
> + if (unlikely(gfpflags & __GFP_ZERO) && object && slab_no_ctor(s))
> memset(object, 0, s->object_size);
>
> slab_post_alloc_hook(s, gfpflags, 1, &object);
Please put this in a code path that is enabled by specifying
slub_debug
on the kernel command line.
