linux的cache分为两类:通用cache(cache_sizes)和专用cache (cache_cache)
两类cache的很多函数都是共用的。
cache相关的数据结构：
1.cache_cache (mm/slab.c)
674 /* internal cache of cache description objs */
675 static struct kmem_cache cache_cache = {
676 .batchcount = 1,
677 .limit = BOOT_CPUCACHE_ENTRIES,
678 .shared = 1,
679 .buffer_size = sizeof(struct kmem_cache),
680 .name = "kmem_cache",
681 #if DEBUG 682 .obj_size = sizeof(struct kmem_cache),
683 #endif
684 };
2.kmem_cache (mm/slab.c)
381 struct kmem_cache {
382 /* 1) per-cpu data, touched during every alloc/free */
383 struct array_cache *array[NR_CPUS];
384 /* 2) Cache tunables. Protected by cache_chain_mutex */
385 unsigned int batchcount;
386 unsigned int limit;
387 unsigned int shared;
388
389 unsigned int buffer_size;
390 u32 reciprocal_buffer_size;
391 /* 3) touched by every alloc & free from the backend */
392 struct kmem_list3 *nodelists[MAX_NUMNODES]; //维护着free,full,patrial三个slab队列
393
394 unsigned int flags; /* constant flags */
//在初始化的时候计算出来，每个slab包含的对象个数
395 unsigned int num; /* # of objs per slab */
396
397 /* 4) cache_grow/shrink */
398 /* order of pgs per slab (2^n) */
399 unsigned int gfporder; //每个slab需要的页面数（2的n次方）
400
401 /* force GFP flags, e.g. GFP_DMA */
402 gfp_t gfpflags;
403//关于colour和colour_off我会专门撰文讲解
404 size_t colour; /* cache colouring range */
405 unsigned int colour_off; /* colour offset */
406 struct kmem_cache *slabp_cache; //如果slab结构指针（分开存储时候）
407 unsigned int slab_size; //kmem_bufctl_t数组和slab的大小
408 unsigned int dflags; /* dynamic flags */
409
410 /* 构造函数 */
411 void (*ctor) (void *, struct kmem_cache *, unsigned long);
412
413 /* 析构函数 */
414 void (*dtor) (void *, struct kmem_cache *, unsigned long);
415
416 /* 5) cache creation/removal */
417 const char *name; //该cache出现在proc中的名字
418 struct list_head next;
447 };
Trackback: http://tb.donews.net/TrackBack.aspx?PostId=1177943