Re: [RFC PATCH 5/5] kmemtrace: SLOB hooks.

From: Pekka Enberg
Date: Fri Jul 11 2008 - 04:44:48 EST


Hi,

Matt, can you take a look at this? I know you don't want *debugging*
code in SLOB but this is for instrumentation.

On Thu, Jul 10, 2008 at 9:06 PM, Eduard - Gabriel Munteanu
<eduard.munteanu@xxxxxxxxxxx> wrote:
> This adds hooks for the SLOB allocator, to allow tracing with kmemtrace.
>
> Signed-off-by: Eduard - Gabriel Munteanu <eduard.munteanu@xxxxxxxxxxx>
> ---
> mm/slob.c | 37 +++++++++++++++++++++++++++++++------
> 1 files changed, 31 insertions(+), 6 deletions(-)
>
> diff --git a/mm/slob.c b/mm/slob.c
> index a3ad667..44f395a 100644
> --- a/mm/slob.c
> +++ b/mm/slob.c
> @@ -65,6 +65,7 @@
> #include <linux/module.h>
> #include <linux/rcupdate.h>
> #include <linux/list.h>
> +#include <linux/kmemtrace.h>
> #include <asm/atomic.h>
>
> /*
> @@ -463,27 +464,38 @@ void *__kmalloc_node(size_t size, gfp_t gfp, int node)
> {
> unsigned int *m;
> int align = max(ARCH_KMALLOC_MINALIGN, ARCH_SLAB_MINALIGN);
> + void *ret;
>
> if (size < PAGE_SIZE - align) {
> if (!size)
> return ZERO_SIZE_PTR;
>
> m = slob_alloc(size + align, gfp, align, node);
> +
> if (!m)
> return NULL;
> *m = size;
> - return (void *)m + align;
> + ret = (void *)m + align;
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_KIND_KERNEL,
> + _RET_IP_, ret,
> + size, size + align, gfp, node);
> } else {
> - void *ret;
> + unsigned int order = get_order(size);
>
> - ret = slob_new_page(gfp | __GFP_COMP, get_order(size), node);
> + ret = slob_new_page(gfp | __GFP_COMP, order, node);
> if (ret) {
> struct page *page;
> page = virt_to_page(ret);
> page->private = size;
> }
> - return ret;
> +
> + kmemtrace_mark_alloc_node(KMEMTRACE_KIND_KERNEL,

The latter case is actually page allocator pass-through so I wonder if
we want to use KIND_PAGES here instead?

> + _RET_IP_, ret,
> + size, PAGE_SIZE << order, gfp, node);
> }
> +
> + return ret;
> }
> EXPORT_SYMBOL(__kmalloc_node);
>
> @@ -501,6 +513,8 @@ void kfree(const void *block)
> slob_free(m, *m + align);
> } else
> put_page(&sp->page);
> +
> + kmemtrace_mark_free(KMEMTRACE_KIND_KERNEL, _RET_IP_, block);

Same comment here.

> }
> EXPORT_SYMBOL(kfree);
>
> @@ -569,10 +583,19 @@ void *kmem_cache_alloc_node(struct kmem_cache *c, gfp_t flags, int node)
> {
> void *b;
>
> - if (c->size < PAGE_SIZE)
> + if (c->size < PAGE_SIZE) {
> b = slob_alloc(c->size, flags, c->align, node);
> - else
> + kmemtrace_mark_alloc_node(KMEMTRACE_KIND_CACHE,
> + _RET_IP_, b, c->size,
> + SLOB_UNITS(c->size) * SLOB_UNIT,
> + flags, node);
> + } else {
> b = slob_new_page(flags, get_order(c->size), node);
> + kmemtrace_mark_alloc_node(KMEMTRACE_KIND_CACHE,
> + _RET_IP_, b, c->size,
> + PAGE_SIZE << get_order(c->size),
> + flags, node);
> + }
>
> if (c->ctor)
> c->ctor(c, b);
> @@ -608,6 +631,8 @@ void kmem_cache_free(struct kmem_cache *c, void *b)
> } else {
> __kmem_cache_free(b, c->size);
> }
> +
> + kmemtrace_mark_free(KMEMTRACE_KIND_CACHE, _RET_IP_, b);
> }
> EXPORT_SYMBOL(kmem_cache_free);
>
> --
> 1.5.6.1
>
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