1 | #ifndef JEMALLOC_INTERNAL_RTREE_CTX_H |
2 | #define JEMALLOC_INTERNAL_RTREE_CTX_H |
3 | |
4 | /* |
5 | * Number of leafkey/leaf pairs to cache in L1 and L2 level respectively. Each |
6 | * entry supports an entire leaf, so the cache hit rate is typically high even |
7 | * with a small number of entries. In rare cases extent activity will straddle |
8 | * the boundary between two leaf nodes. Furthermore, an arena may use a |
9 | * combination of dss and mmap. Note that as memory usage grows past the amount |
10 | * that this cache can directly cover, the cache will become less effective if |
11 | * locality of reference is low, but the consequence is merely cache misses |
12 | * while traversing the tree nodes. |
13 | * |
14 | * The L1 direct mapped cache offers consistent and low cost on cache hit. |
15 | * However collision could affect hit rate negatively. This is resolved by |
16 | * combining with a L2 LRU cache, which requires linear search and re-ordering |
17 | * on access but suffers no collision. Note that, the cache will itself suffer |
18 | * cache misses if made overly large, plus the cost of linear search in the LRU |
19 | * cache. |
20 | */ |
21 | #define RTREE_CTX_LG_NCACHE 4 |
22 | #define RTREE_CTX_NCACHE (1 << RTREE_CTX_LG_NCACHE) |
23 | #define RTREE_CTX_NCACHE_L2 8 |
24 | |
25 | /* |
26 | * Zero initializer required for tsd initialization only. Proper initialization |
27 | * done via rtree_ctx_data_init(). |
28 | */ |
29 | #define RTREE_CTX_ZERO_INITIALIZER {{{0, 0}}, {{0, 0}}} |
30 | |
31 | |
32 | typedef struct rtree_leaf_elm_s rtree_leaf_elm_t; |
33 | |
34 | typedef struct rtree_ctx_cache_elm_s rtree_ctx_cache_elm_t; |
35 | struct rtree_ctx_cache_elm_s { |
36 | uintptr_t leafkey; |
37 | rtree_leaf_elm_t *leaf; |
38 | }; |
39 | |
40 | typedef struct rtree_ctx_s rtree_ctx_t; |
41 | struct rtree_ctx_s { |
42 | /* Direct mapped cache. */ |
43 | rtree_ctx_cache_elm_t cache[RTREE_CTX_NCACHE]; |
44 | /* L2 LRU cache. */ |
45 | rtree_ctx_cache_elm_t l2_cache[RTREE_CTX_NCACHE_L2]; |
46 | }; |
47 | |
48 | void rtree_ctx_data_init(rtree_ctx_t *ctx); |
49 | |
50 | #endif /* JEMALLOC_INTERNAL_RTREE_CTX_H */ |
51 | |