2022-04-15 05:48:31

by Hyeonggon Yoo

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Subject: [PATCH v2 08/23] mm/slab_common: make kmalloc_large_node() consistent with kmalloc_large()

Move tracepoints into kmalloc_large_node() and add missing flag fix code.

Signed-off-by: Hyeonggon Yoo <[email protected]>
---
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);

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);
-
- 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);

s = kmalloc_slab(size, gfpflags);

--
2.32.0


2022-04-27 10:01:33

by Vlastimil Babka

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Subject: Re: [PATCH v2 08/23] mm/slab_common: make kmalloc_large_node() consistent with kmalloc_large()

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 <[email protected]>

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);
>

2022-04-28 08:56:48

by Hyeonggon Yoo

[permalink] [raw]
Subject: Re: [PATCH v2 08/23] mm/slab_common: make kmalloc_large_node() consistent with kmalloc_large()

On Tue, Apr 26, 2022 at 07:15:06PM +0200, Vlastimil Babka wrote:
> 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 <[email protected]>
>

Hello Vlastimil, thanks for review! ;-)

> 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.

kmalloc_large() had the exact problem before my series when called from __kmalloc().

On top of current slab/for-next:
[000] ..... 43.172574: kmalloc: call_site=__kmalloc+0x2aa/0x300 ptr=ffff88e2183a0000 bytes_req=12368 bytes_alloc=16384 gfp_flags=GFP_KERNEL

Considering different usecases of kmalloc_large_node() (called from kmalloc_node() or __kmalloc_node()),
I think we need trace/notrace version of kmalloc_large_node().

>
> 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'.
>

Thanks for catching this.
I think notrace version + tracepoint would fit here.

> >
> > s = kmalloc_slab(size, gfpflags);
> >
>

--
Thanks,
Hyeonggon