Re: [PATCH] Uninline kcalloc()

From: Valdis . Kletnieks
Date: Mon Sep 24 2007 - 03:55:32 EST


On Mon, 24 Sep 2007 11:44:35 +0400, Alexey Dobriyan said:
> On 9/24/07, Valdis.Kletnieks@xxxxxx <Valdis.Kletnieks@xxxxxx> wrote:
> > On Sun, 23 Sep 2007 00:03:49 +0400, Alexey Dobriyan said:
> >
> > > -static inline void *kcalloc(size_t n, size_t size, gfp_t flags)
> > > -{
> > > - if (n != 0 && size > ULONG_MAX / n)
> > > - return NULL;
> > > - return __kmalloc(n * size, flags | __GFP_ZERO);
> > > -}
> > > +void *kcalloc(size_t n, size_t size, gfp_t flags);
> >
> > NAK.
> >
> > This busticates some pretty subtle code in mm/slab.c that uses
> > uses __builtin_return_address() for debugging
>
> Interesting. Here is output from kernel with patch applied and leak
> plugged into proc_dointvec() (I checked twice):
>
> $ grep kcalloc /proc/slab_allocators

Right. That was the whole *point* of the patch to inline kcalloc - otherwise
you ended up with zillions of entries for kcalloc that didn't tell you where
they came from.

> $ grep proc_dointvec /proc/slab_allocators
> size-64: 19 proc_dointvec+0x48/0xa0

A lot more useful, no? ;)
<confoozled> I'm failing to see where proc_dointvec() ends up calling kcalloc?
So I'm not sure what that's

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