Re: [RFC PATCH 2/4] kmemtrace: SLAB hooks.
From: Pekka Enberg
Date: Thu Jul 17 2008 - 03:39:06 EST
Hi Eduard-Gabriel,
On Thu, Jul 17, 2008 at 3:46 AM, Eduard - Gabriel Munteanu
<eduard.munteanu@xxxxxxxxxxx> wrote:
> This adds hooks for the SLAB allocator, to allow tracing with kmemtrace.
>
> Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@xxxxxxxxxxx>
> ---
> include/linux/slab_def.h | 56 +++++++++++++++++++++++++++++++++++++-----
> mm/slab.c | 61 +++++++++++++++++++++++++++++++++++++++++----
> 2 files changed, 104 insertions(+), 13 deletions(-)
>
> diff --git a/include/linux/slab_def.h b/include/linux/slab_def.h
> index 39c3a5e..77b8045 100644
> --- a/include/linux/slab_def.h
> +++ b/include/linux/slab_def.h
> @@ -14,6 +14,7 @@
> #include <asm/page.h> /* kmalloc_sizes.h needs PAGE_SIZE */
> #include <asm/cache.h> /* kmalloc_sizes.h needs L1_CACHE_BYTES */
> #include <linux/compiler.h>
> +#include <linux/kmemtrace.h>
>
> /* Size description struct for general caches. */
> struct cache_sizes {
> @@ -28,8 +29,20 @@ extern struct cache_sizes malloc_sizes[];
> void *kmem_cache_alloc(struct kmem_cache *, gfp_t);
> void *__kmalloc(size_t size, gfp_t flags);
>
> +#ifdef CONFIG_KMEMTRACE
> +extern void *kmem_cache_alloc_notrace(struct kmem_cache *cachep, gfp_t flags);
> +#else
> +static inline void *kmem_cache_alloc_notrace(struct kmem_cache *cachep,
> + gfp_t flags)
> +{
> + return kmem_cache_alloc(cachep, flags);
> +}
> +#endif
> +
> static inline void *kmalloc(size_t size, gfp_t flags)
> {
> + void *ret;
> +
> if (__builtin_constant_p(size)) {
> int i = 0;
>
> @@ -50,10 +63,17 @@ static inline void *kmalloc(size_t size, gfp_t flags)
> found:
> #ifdef CONFIG_ZONE_DMA
> if (flags & GFP_DMA)
> - return kmem_cache_alloc(malloc_sizes[i].cs_dmacachep,
> - flags);
> + ret = kmem_cache_alloc_notrace(
> + malloc_sizes[i].cs_dmacachep, flags);
> + else
> #endif
> - return kmem_cache_alloc(malloc_sizes[i].cs_cachep, flags);
> + ret = kmem_cache_alloc_notrace(
> + malloc_sizes[i].cs_cachep, flags);
> +
> + kmemtrace_mark_alloc(KMEMTRACE_TYPE_KERNEL, _THIS_IP_, ret,
> + size, malloc_sizes[i].cs_size, flags);
We have malloc_sizes[i].cs_size here as the _allocated_ size (which
seems wrong to be btw).
> +
> + return ret;
> }
> return __kmalloc(size, flags);
> }
> @@ -62,8 +82,23 @@ found:
> extern void *__kmalloc_node(size_t size, gfp_t flags, int node);
> extern void *kmem_cache_alloc_node(struct kmem_cache *, gfp_t flags, int node);
>
> +#ifdef CONFIG_KMEMTRACE
> +extern void *kmem_cache_alloc_node_notrace(struct kmem_cache *cachep,
> + gfp_t flags,
> + int nodeid);
> +#else
> +static inline void *kmem_cache_alloc_node_notrace(struct kmem_cache *cachep,
> + gfp_t flags,
> + int nodeid)
> +{
> + return kmem_cache_alloc_node(cachep, flags, nodeid);
> +}
> +#endif
> +
> static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
> {
> + void *ret;
> +
> if (__builtin_constant_p(size)) {
> int i = 0;
>
> @@ -84,11 +119,18 @@ static inline void *kmalloc_node(size_t size, gfp_t flags, int node)
> found:
> #ifdef CONFIG_ZONE_DMA
> if (flags & GFP_DMA)
> - return kmem_cache_alloc_node(malloc_sizes[i].cs_dmacachep,
> - flags, node);
> + ret = kmem_cache_alloc_node_notrace(
> + malloc_sizes[i].cs_dmacachep, flags, node);
> + else
> #endif
> - return kmem_cache_alloc_node(malloc_sizes[i].cs_cachep,
> - flags, node);
> + ret = kmem_cache_alloc_node_notrace(
> + malloc_sizes[i].cs_cachep, flags, node);
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_TYPE_KERNEL, _THIS_IP_,
> + ret, size, malloc_sizes[i].cs_size,
> + flags, node);
And here.
> +
> + return ret;
> }
> return __kmalloc_node(size, flags, node);
> }
>
> +#ifdef CONFIG_KMEMTRACE
> +void *kmem_cache_alloc_node_notrace(struct kmem_cache *cachep,
> + gfp_t flags,
> + int nodeid)
> +{
> + return __cache_alloc_node(cachep, flags, nodeid,
> + __builtin_return_address(0));
> +}
> +EXPORT_SYMBOL(kmem_cache_alloc_node_notrace);
> +#endif
> +
> static __always_inline void *
> __do_kmalloc_node(size_t size, gfp_t flags, int node, void *caller)
> {
> struct kmem_cache *cachep;
> + void *ret;
>
> cachep = kmem_find_general_cachep(size, flags);
> if (unlikely(ZERO_OR_NULL_PTR(cachep)))
> return cachep;
> - return kmem_cache_alloc_node(cachep, flags, node);
> + ret = kmem_cache_alloc_node_notrace(cachep, flags, node);
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_TYPE_KERNEL,
> + (unsigned long) caller, ret,
> + size, cachep->buffer_size, flags, node);
But here we use cachep->buffer_size and...
> +
> + return ret;
> }
>
> #ifdef CONFIG_DEBUG_SLAB
> @@ -3718,6 +3756,7 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
> void *caller)
> {
> struct kmem_cache *cachep;
> + void *ret;
>
> /* If you want to save a few bytes .text space: replace
> * __ with kmem_.
> @@ -3727,11 +3766,17 @@ static __always_inline void *__do_kmalloc(size_t size, gfp_t flags,
> cachep = __find_general_cachep(size, flags);
> if (unlikely(ZERO_OR_NULL_PTR(cachep)))
> return cachep;
> - return __cache_alloc(cachep, flags, caller);
> + ret = __cache_alloc(cachep, flags, caller);
> +
> + kmemtrace_mark_alloc(KMEMTRACE_TYPE_KERNEL,
> + (unsigned long) caller, ret,
> + size, cachep->buffer_size, flags);
...here as well. Why?
Also,
> diff --git a/mm/slab.c b/mm/slab.c
> index 046607f..e9a61ac 100644
> --- a/mm/slab.c
> +++ b/mm/slab.c
> @@ -111,6 +111,7 @@
> #include <linux/rtmutex.h>
> #include <linux/reciprocal_div.h>
> #include <linux/debugobjects.h>
> +#include <linux/kmemtrace.h>
>
> #include <asm/cacheflush.h>
> #include <asm/tlbflush.h>
> @@ -3621,10 +3622,23 @@ static inline void __cache_free(struct kmem_cache *cachep, void *objp)
> */
> void *kmem_cache_alloc(struct kmem_cache *cachep, gfp_t flags)
> {
> - return __cache_alloc(cachep, flags, __builtin_return_address(0));
> + void *ret = __cache_alloc(cachep, flags, __builtin_return_address(0));
> +
> + kmemtrace_mark_alloc(KMEMTRACE_TYPE_CACHE, _RET_IP_, ret,
> + obj_size(cachep), obj_size(cachep), flags);
Here....
> +
> + return ret;
> }
> EXPORT_SYMBOL(kmem_cache_alloc);
>
> +#ifdef CONFIG_KMEMTRACE
> +void *kmem_cache_alloc_notrace(struct kmem_cache *cachep, gfp_t flags)
> +{
> + return __cache_alloc(cachep, flags, __builtin_return_address(0));
> +}
> +EXPORT_SYMBOL(kmem_cache_alloc_notrace);
> +#endif
> +
> /**
> * kmem_ptr_validate - check if an untrusted pointer might be a slab entry.
> * @cachep: the cache we're checking against
> @@ -3669,20 +3683,44 @@ out:
> #ifdef CONFIG_NUMA
> void *kmem_cache_alloc_node(struct kmem_cache *cachep, gfp_t flags, int nodeid)
> {
> - return __cache_alloc_node(cachep, flags, nodeid,
> - __builtin_return_address(0));
> + void *ret = __cache_alloc_node(cachep, flags, nodeid,
> + __builtin_return_address(0));
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_TYPE_CACHE, _RET_IP_, ret,
> + obj_size(cachep), obj_size(cachep),
> + flags, nodeid);
...and here, we use obj_size().
> +
> + return ret;
> }
> EXPORT_SYMBOL(kmem_cache_alloc_node);
AFAICT, you should always use ->buffer_size as the_allocated_ size. Hmm?
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