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1. ǰÑÔ
kmem_cacheÊÇLinuxÄÚºËÌṩµÄ¿ìËÙÄڴ滺³å½Ó¿Ú£¬ÕâЩÄÚ´æ¿éÒªÇóÊÇ´óСÏàͬµÄ£¬ÒòΪ·ÖÅä³öµÄÄÚ
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µã£¬skbuffÍ·, netfilterµÄÁ¬½ÓµÈ£¬ÆäʵkmallocÒ²ÊÇ´Ókmem_cacheÖзÖÅäµÄ£¬¿Éͨ
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2. slabºÍpage
ÔÚ½éÉÜkmem_cache֮ǰÐèÒªÏȽéÉÜpageºÍslabÕâÁ½¸ö¶¨Òå¡£ÖÚËùÖÜÖª£¬pageÊÇÄÚºËÖÐÄÚ´æ»ù±¾¹ÜÀíµ¥
λ£¬Ã¿¸öpageµÄÄÚ´æ´óСÊǹ̶¨µÄ£¬¶ÔX86»úÆ÷À´Ëµ£¬ÊÇ4K£»slabÔòÊÇkmem_cacheµÄ¾ßÌåµÄÄÚ´æ¿Õ¼ä
ÐÎʽ£¬¸ù¾ÝcacheµÄ¶ÔÏóµÄ´óС£¬Ã¿¸öslab¿ÉÒÔÓÐ1¸öpageµ½×î¶à32(128/4)¸öpage£»Èç¹ûcache¶ÔÏó±È
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struct slab {
// Á´±í
struct list_head list;
// δÓÿռäµÄÆ«ÒÆ
unsigned long colouroff;
// ¾ßÌåµÄÄڴ滺³åÇøµØÖ·
void *s_mem; /* including colour offset */
// ÿ¸öslabÖеÄÕýÔÚʹÓõĶÔÏóÊýÁ¿
unsigned int inuse; /* num of objs active in slab */
// ¿ÕÏжÔÏó
kmem_bufctl_t free;
unsigned short nodeid;
};
3. Êý¾Ý½á¹¹
kmem_cacheÊý¾Ý½á¹¹²¢Ã»Óж¨ÒåÔÚ.hµÄÍ·ÎļþÖУ¬ÔÚÍ·ÎļþÖÐÖ»ÊǸýṹµÄÒ»¸öÀàÐͶ¨Ò壬ÒòΪÆäËû
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/* include/linux/slab.h */
// ÕâÀïÖ»ÊÇÒ»¸öÀàÐͶ¨Òå
typedef struct kmem_cache kmem_cache_t;
/* mm/slab.c */
// ÔÚCÎļþÖнøÐÐÍêÕûµÄ¶¨Òå
/*
* struct array_cache
*
* Purpose:
* - LIFO ordering, to hand out cache-warm objects from _alloc
* - reduce the number of linked list operations
* - reduce spinlock operations
*
* The limit is stored in the per-cpu structure to reduce the data cache
* footprint.
*
*/
// ÕâÊÇÿ¸öCPU¶ÔÓ¦µÄcacheÊý¾Ý
struct array_cache {
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