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void kmem_cache_free (kmem_cache_t *cachep, void *objp)
{
     unsigned long flags;
 
     local_irq_save(flags);
     __cache_free(cachep, objp);
     local_irq_restore(flags);
}
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static inline void __cache_free (kmem_cache_t *cachep, void* objp)
{
     struct array_cache *ac = ac_data(cachep);
 
     check_irq_off();
     //DEBUGÓ㬺öÂÔ
     objp = cache_free_debugcheck(cachep, objp, __builtin_return_address(0));
     //Èç¹ûACÖеĶÔÏñûÓг¬¹ýÏÞÖÆ£¬ÄǾͰÑËüÊͷŵ½ACÖС£
     if (likely(ac->avail < ac->limit)) {
         STATS_INC_FREEHIT(cachep);
         ac_entry(ac)[ac->avail++] = objp;
         return;
     } else {
         //Èç¹ûACÖжÔÏóÊýÄ¿µ½ÁËÏÞÖµ£¬Ôòcache_flusharray£¨£©ºó£¬ÔٰѶÔÏñ¼ÓÈëACÖÐ
         STATS_INC_FREEMISS(cachep);
         cache_flusharray(cachep, ac);
         ac_entry(ac)[ac->avail++] = objp;
     }
}
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static void cache_flusharray (kmem_cache_t* cachep, struct array_cache *ac)
{
     int batchcount;