Re: CK2 [08/15] slab: Use common kmalloc_index/kmalloc_size functions

[JoonSoo Kim <js1304@gmail.com>]

2012/10/24 Christoph Lameter <cl@linux.com>:
> On Sun, 21 Oct 2012, JoonSoo Kim wrote:
>
>> 2012/10/19 Christoph Lameter <cl@linux.com>:
>>
>> > @@ -693,20 +657,19 @@ static inline struct array_cache *cpu_ca
>> >  static inline struct kmem_cache *__find_general_cachep(size_t size,
>> >                                                         gfp_t gfpflags)
>> >  {
>> > -       struct cache_sizes *csizep = malloc_sizes;
>> > +       int i;
>> >
>> >  #if DEBUG
>> >         /* This happens if someone tries to call
>> >          * kmem_cache_create(), or __kmalloc(), before
>> >          * the generic caches are initialized.
>> >          */
>> > -       BUG_ON(malloc_sizes[INDEX_AC].cs_cachep == NULL);
>> > +       BUG_ON(kmalloc_caches[INDEX_AC] == NULL);
>> >  #endif
>> >         if (!size)
>> >                 return ZERO_SIZE_PTR;
>> >
>> > -       while (size > csizep->cs_size)
>> > -               csizep++;
>> > +       i = kmalloc_index(size);
>>
>> Above kmalloc_index(size) is called with arbitrary size, therefore it
>> cannot be folded.
>
> The size is passed into an inline function that is folded and therefore
> the kmalloc_index function can also be folded if the size passed into
> __find_general_cachep was constant.
>

__find_general_cachep() is called by __do_kmalloc().
And __do_kmalloc() is called by __kmalloc().
__kmalloc() is called by kmalloc() when buildin_constant_p is failed.
Therefore __find_general_cachep() is called with arbitrary size value
and kmalloc_index() cannot be folded.
But, I think it doesn't matter, because CK2[15/15] also solve this problem.

Thanks.

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