On 4/14/22 10:57, Hyeonggon Yoo wrote:
> Move tracepoints into kmalloc_large_node() and add missing flag fix code.
>
> Signed-off-by: Hyeonggon Yoo <42.hyeyoo@xxxxxxxxx>
Hm so there's a problem with the tracepoint's caller.
kmalloc_large() is only called from kmalloc() which is an inline thus the
callsite of kmalloc() calls directly kmalloc_large(). So when
kmalloc_large() does "trace_kmalloc(_RET_IP_, ...)" the _RET_IP_ is the
callsite of kmalloc(), which is what we want.
But with kmalloc_large_node()...
> ---
> mm/slab_common.c | 6 ++++++
> mm/slub.c | 22 ++++------------------
> 2 files changed, 10 insertions(+), 18 deletions(-)
>
> diff --git a/mm/slab_common.c b/mm/slab_common.c
> index e72089515030..cf17be8cd9ad 100644
> --- a/mm/slab_common.c
> +++ b/mm/slab_common.c
> @@ -955,6 +955,9 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node)
> void *ptr = NULL;
> unsigned int order = get_order(size);
>
> + if (unlikely(flags & GFP_SLAB_BUG_MASK))
> + flags = kmalloc_fix_flags(flags);
> +
> flags |= __GFP_COMP;
> page = alloc_pages_node(node, flags, order);
> if (page) {
> @@ -966,6 +969,9 @@ void *kmalloc_large_node(size_t size, gfp_t flags, int node)
> ptr = kasan_kmalloc_large(ptr, size, flags);
> /* As ptr might get tagged, call kmemleak hook after KASAN. */
> kmemleak_alloc(ptr, size, 1, flags);
> + trace_kmalloc_node(_RET_IP_, ptr,
> + size, PAGE_SIZE << order,
> + flags, node);
... the _RET_IP_ here would be __kmalloc_node() which is not useful.
> return ptr;
> }
> diff --git a/mm/slub.c b/mm/slub.c
> index 640712706f2b..f10a892f1772 100644
> --- a/mm/slub.c
> +++ b/mm/slub.c
> @@ -4396,15 +4396,8 @@ void *__kmalloc_node(size_t size, gfp_t flags, int node)
> struct kmem_cache *s;
> void *ret;
>
> - if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
> - ret = kmalloc_large_node(size, flags, node);
> -
> - trace_kmalloc_node(_RET_IP_, ret,
> - size, PAGE_SIZE << get_order(size),
> - flags, node);
Here it was OK because __kmalloc_node is expanded from something inline
coming from slab.h.
> -
> - return ret;
> - }
> + if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
> + return kmalloc_large_node(size, flags, node);
>
> s = kmalloc_slab(size, flags);
>
> @@ -4861,15 +4854,8 @@ void *__kmalloc_node_track_caller(size_t size, gfp_t gfpflags,
> struct kmem_cache *s;
> void *ret;
>
> - if (unlikely(size > KMALLOC_MAX_CACHE_SIZE)) {
> - ret = kmalloc_large_node(size, gfpflags, node);
> -
> - trace_kmalloc_node(caller, ret,
> - size, PAGE_SIZE << get_order(size),
> - gfpflags, node);
> -
> - return ret;
> - }
> + if (unlikely(size > KMALLOC_MAX_CACHE_SIZE))
> + return kmalloc_large_node(size, gfpflags, node);
And here it even forgets the 'caller'.
>
> s = kmalloc_slab(size, gfpflags);
>
