Re: [RFC PATCH 3/4] kmemtrace: SLUB hooks.

From: Pekka Enberg
Date: Thu Jul 17 2008 - 03:47:07 EST


On Thu, Jul 17, 2008 at 3:46 AM, Eduard - Gabriel Munteanu
<eduard.munteanu@xxxxxxxxxxx> wrote:
> This adds hooks for the SLUB allocator, to allow tracing with kmemtrace.
>
> Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@xxxxxxxxxxx>
> ---
> include/linux/slub_def.h | 9 +++++++-
> mm/slub.c | 47 ++++++++++++++++++++++++++++++++++++++++-----
> 2 files changed, 49 insertions(+), 7 deletions(-)
>
> diff --git a/include/linux/slub_def.h b/include/linux/slub_def.h
> index d117ea2..0cef121 100644
> --- a/include/linux/slub_def.h
> +++ b/include/linux/slub_def.h
> @@ -10,6 +10,7 @@
> #include <linux/gfp.h>
> #include <linux/workqueue.h>
> #include <linux/kobject.h>
> +#include <linux/kmemtrace.h>
>
> enum stat_item {
> ALLOC_FASTPATH, /* Allocation from cpu slab */
> @@ -205,7 +206,13 @@ void *__kmalloc(size_t size, gfp_t flags);
>
> static __always_inline void *kmalloc_large(size_t size, gfp_t flags)
> {
> - return (void *)__get_free_pages(flags | __GFP_COMP, get_order(size));
> + unsigned int order = get_order(size);
> + void *ret = (void *) __get_free_pages(flags, order);
> +
> + kmemtrace_mark_alloc(KMEMTRACE_TYPE_KERNEL, _THIS_IP_, ret,
> + size, PAGE_SIZE << order, flags);
> +
> + return ret;
> }
>
> static __always_inline void *kmalloc(size_t size, gfp_t flags)
> diff --git a/mm/slub.c b/mm/slub.c
> index 315c392..a6f930f 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -23,6 +23,7 @@
> #include <linux/kallsyms.h>
> #include <linux/memory.h>
> #include <linux/math64.h>
> +#include <linux/kmemtrace.h>
>
> /*
> * Lock order:
> @@ -1652,14 +1653,25 @@ static __always_inline void *slab_alloc(struct kmem_cache *s,
>
> void *kmem_cache_alloc(struct kmem_cache *s, gfp_t gfpflags)
> {
> - return slab_alloc(s, gfpflags, -1, __builtin_return_address(0));
> + void *ret = slab_alloc(s, gfpflags, -1, __builtin_return_address(0));
> +
> + kmemtrace_mark_alloc(KMEMTRACE_TYPE_CACHE, _RET_IP_, ret,
> + s->objsize, s->size, gfpflags);
> +
> + return ret;
> }
> EXPORT_SYMBOL(kmem_cache_alloc);
>
> #ifdef CONFIG_NUMA
> void *kmem_cache_alloc_node(struct kmem_cache *s, gfp_t gfpflags, int node)
> {
> - return slab_alloc(s, gfpflags, node, __builtin_return_address(0));
> + void *ret = slab_alloc(s, gfpflags, node,
> + __builtin_return_address(0));
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_TYPE_CACHE, _RET_IP_, ret,
> + s->objsize, s->size, gfpflags, node);
> +
> + return ret;
> }
> EXPORT_SYMBOL(kmem_cache_alloc_node);
> #endif
> @@ -1771,6 +1783,8 @@ void kmem_cache_free(struct kmem_cache *s, void *x)
> page = virt_to_head_page(x);
>
> slab_free(s, page, x, __builtin_return_address(0));
> +
> + kmemtrace_mark_free(KMEMTRACE_TYPE_CACHE, _RET_IP_, x);
> }
> EXPORT_SYMBOL(kmem_cache_free);
>
> @@ -2676,6 +2690,7 @@ static struct kmem_cache *get_slab(size_t size, gfp_t flags)
> void *__kmalloc(size_t size, gfp_t flags)
> {
> struct kmem_cache *s;
> + void *ret;
>
> if (unlikely(size > PAGE_SIZE))
> return kmalloc_large(size, flags);
> @@ -2685,7 +2700,12 @@ void *__kmalloc(size_t size, gfp_t flags)
> if (unlikely(ZERO_OR_NULL_PTR(s)))
> return s;
>
> - return slab_alloc(s, flags, -1, __builtin_return_address(0));
> + ret = slab_alloc(s, flags, -1, __builtin_return_address(0));
> +
> + kmemtrace_mark_alloc(KMEMTRACE_TYPE_KERNEL, _RET_IP_, ret,
> + size, (size_t) s->size, (unsigned long) flags);

What are these casts doing here? I think you can just drop them, no?

> +
> + return ret;
> }
> EXPORT_SYMBOL(__kmalloc);
>
> @@ -2704,16 +2724,29 @@ static void *kmalloc_large_node(size_t size, gfp_t flags, int node)
> void *__kmalloc_node(size_t size, gfp_t flags, int node)
> {
> struct kmem_cache *s;
> + void *ret;
>
> - if (unlikely(size > PAGE_SIZE))
> - return kmalloc_large_node(size, flags, node);
> + if (unlikely(size > PAGE_SIZE)) {
> + ret = kmalloc_large_node(size, flags, node);
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_TYPE_KERNEL, _RET_IP_, ret,
> + size, PAGE_SIZE << get_order(size),
> + (unsigned long) flags, node);

Don't cast flags to unsigned long. The kmemtrace core should use gfp_t
as the parameter type.

> +
> + return ret;
> + }
>
> s = get_slab(size, flags);
>
> if (unlikely(ZERO_OR_NULL_PTR(s)))
> return s;
>
> - return slab_alloc(s, flags, node, __builtin_return_address(0));
> + ret = slab_alloc(s, flags, node, __builtin_return_address(0));
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_TYPE_KERNEL, _RET_IP_, ret,
> + size, s->size, (unsigned long) flags, node);

Another cast here.

> +
> + return ret;
> }
> EXPORT_SYMBOL(__kmalloc_node);
> #endif
> @@ -2771,6 +2804,8 @@ void kfree(const void *x)
> return;
> }
> slab_free(page->slab, page, object, __builtin_return_address(0));
> +
> + kmemtrace_mark_free(KMEMTRACE_TYPE_KERNEL, _RET_IP_, x);
> }
> EXPORT_SYMBOL(kfree);
>
> --
> 1.5.6.1
>
> --
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