uclinux-2008R1-RC8(bf561)到VDSP5的移植(44)：kmalloc和kzalloc的问题

 

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本文适用于

ADI bf561 DSP

uclinux-2008r1-rc8 (移植到vdsp5)

Visual DSP++ 5.0

 

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这两个函数的定义均在include/linux/slab_def.h中，其实现如下：

static inline void *kmalloc(size_t size, gfp_t flags)

{

     if (__builtin_constant_p(size)) {

         int i = 0;

#define CACHE(x) /

         if (size <= x) /

              goto found; /

         else /

              i++;

#include "kmalloc_sizes.h"

#undef CACHE

         {

              extern void __you_cannot_kmalloc_that_much(void);

              __you_cannot_kmalloc_that_much();

         }

found:

#ifdef CONFIG_ZONE_DMA

         if (flags & GFP_DMA)

              return kmem_cache_alloc(malloc_sizes[i].cs_dmacachep,

                            flags);

#endif

         return kmem_cache_alloc(malloc_sizes[i].cs_cachep, flags);

     }

     return __kmalloc(size, flags);

}

 

static inline void *kzalloc(size_t size, gfp_t flags)

{

     if (__builtin_constant_p(size)) {

         int i = 0;

#define CACHE(x) /

         if (size <= x) /

              goto found; /

         else /

              i++;

#include "kmalloc_sizes.h"

#undef CACHE

         {

              extern void __you_cannot_kzalloc_that_much(void);

              __you_cannot_kzalloc_that_much();

         }

found:

#ifdef CONFIG_ZONE_DMA

         if (flags & GFP_DMA)

              return kmem_cache_zalloc(malloc_sizes[i].cs_dmacachep,

                            flags);

#endif

         return kmem_cache_zalloc(malloc_sizes[i].cs_cachep, flags);

     }

     return __kzalloc(size, flags);

}

在这两个函数中，根据size是否为编译时常数做了优化，但是在移植时由于VDSP5不支持__builtin_constant_p这个宏，因此直接将这两个函数改为：

static inline void *kmalloc(size_t size, gfp_t flags)

{

     if (__builtin_constant_p(size)) {

         int i = 0;

#define CACHE(x) /

         if (size <= x) /

              goto found; /

         else /

              i++;

#include "kmalloc_sizes.h"

#undef CACHE

//       {

//            extern void __you_cannot_kmalloc_that_much(void);

//            __you_cannot_kmalloc_that_much();

//       }

found:

#ifdef CONFIG_ZONE_DMA

//       if (flags & GFP_DMA)

//            return kmem_cache_alloc(malloc_sizes[i].cs_dmacachep,

//                          flags);

#endif

//       return kmem_cache_alloc(malloc_sizes[i].cs_cachep, flags);

     }

     return __kmalloc(size, flags);

}

 

static inline void *kzalloc(size_t size, gfp_t flags)

{

     if (__builtin_constant_p(size)) {

         int i = 0;

#define CACHE(x) /

         if (size <= x) /

              goto found; /

         else /

              i++;

#include "kmalloc_sizes.h"

#undef CACHE

//       {

//            extern void __you_cannot_kzalloc_that_much(void);

//            __you_cannot_kzalloc_that_much();

//       }

found:

#ifdef CONFIG_ZONE_DMA

//       if (flags & GFP_DMA)

//            return kmem_cache_zalloc(malloc_sizes[i].cs_dmacachep,

//                          flags);

#endif

//       return kmem_cache_zalloc(malloc_sizes[i].cs_cachep, flags);

     }

     return __kzalloc(size, flags);

}

虽然对性能会略有影响，但是也能完成正确的功能。