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Áù£ºkmem_cache_allocµÄʵÏÖ·ÖÎö:
ÎÒÃÇÔÚÉÏÃæ¿ÉÒÔ¿´µ½£¬´´½¨Ò»¸öcacheÃèÊö·ûµÄʱºò£¬²¢Ã»ÓÐÕâÖ®·ÖÅäslabÊý¾Ý¡£ÏÖÔÚÎÒÃÇÀ´¿´Ò»ÏÂÔõô´ÓcacheÖÐÉêÇë¶ÔÏó
void * kmem_cache_alloc (kmem_cache_t *cachep, int flags)
{
     return __cache_alloc(cachep, flags);
}
ʵ¼ÊÉÏ»áµ÷ÓÃ__cache_alloc
ÈçÏ£º
static inline void * __cache_alloc (kmem_cache_t *cachep, int flags)
{
     unsigned long save_flags;
     void* objp;
     struct array_cache *ac;
     //Èç¹û¶¨ÒåÁË__GFP_WAIT¡£¿ÉÄÜ»áÒýÆð˯Ãß
     cache_alloc_debugcheck_before(cachep, flags);
 
     local_irq_save(save_flags);
     //È¡µÃµ±Ç°´¦ÀíÆ÷ËùÔÚµÄarray_cache(¼ò³ÆΪAC£¬ÎÒÃÇÏÂÃæÒ²ÕâÑù³ÆºôËü)
     ac = ac_data(cachep);
     //ac->avail:ACÖеںóÒ»¸ö¿ÉÓõĶÔÏóË÷Òý
    
//Èç¹ûACÖл¹ÓпÉÓõĶÔÏó
if (likely(ac->avail)) {
         STATS_INC_ALLOCHIT(cachep);
         //ÿ´Î·ÖÅ䶼»á°Ñac->touchedÖÃΪ1
         ac->touched = 1;
         objp = ac_entry(ac)[--ac->avail];
     } else {
         //Èç¹ûACÖÐûÓпÉÓöÔÏó£¬ÄÇÖ»ÄÜ´Ól3ÖГ°á³ö”¶ÔÏóµ½ACÖÐ
         STATS_INC_ALLOCMISS(cachep);
         objp = cache_alloc_refill(cachep, flags);
     }
     local_irq_restore(save_flags);
     objp = cache_alloc_debugcheck_after(cachep, flags, objp, __builtin_return_address(0));
     return objp;
}
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