Mercurial > hg > nginx
view src/core/ngx_radix_tree.c @ 8078:5244d3b165ff
SSL: single allocation in session cache on 32-bit platforms.
Given the present typical SSL session sizes, on 32-bit platforms it is
now beneficial to store all data in a single allocation, since rbtree
node + session id + ASN1 representation of a session takes 256 bytes of
shared memory (36 + 32 + 150 = about 218 bytes plus SNI server name).
Storing all data in a single allocation is beneficial for SNI names up to
about 40 characters long and makes it possible to store about 4000 sessions
in one megabyte (instead of about 3000 sessions now). This also slightly
simplifies the code.
author | Maxim Dounin <mdounin@mdounin.ru> |
---|---|
date | Wed, 12 Oct 2022 20:14:40 +0300 |
parents | 3be3de31d7dd |
children |
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/* * Copyright (C) Igor Sysoev * Copyright (C) Nginx, Inc. */ #include <ngx_config.h> #include <ngx_core.h> static ngx_radix_node_t *ngx_radix_alloc(ngx_radix_tree_t *tree); ngx_radix_tree_t * ngx_radix_tree_create(ngx_pool_t *pool, ngx_int_t preallocate) { uint32_t key, mask, inc; ngx_radix_tree_t *tree; tree = ngx_palloc(pool, sizeof(ngx_radix_tree_t)); if (tree == NULL) { return NULL; } tree->pool = pool; tree->free = NULL; tree->start = NULL; tree->size = 0; tree->root = ngx_radix_alloc(tree); if (tree->root == NULL) { return NULL; } tree->root->right = NULL; tree->root->left = NULL; tree->root->parent = NULL; tree->root->value = NGX_RADIX_NO_VALUE; if (preallocate == 0) { return tree; } /* * Preallocation of first nodes : 0, 1, 00, 01, 10, 11, 000, 001, etc. * increases TLB hits even if for first lookup iterations. * On 32-bit platforms the 7 preallocated bits takes continuous 4K, * 8 - 8K, 9 - 16K, etc. On 64-bit platforms the 6 preallocated bits * takes continuous 4K, 7 - 8K, 8 - 16K, etc. There is no sense to * to preallocate more than one page, because further preallocation * distributes the only bit per page. Instead, a random insertion * may distribute several bits per page. * * Thus, by default we preallocate maximum * 6 bits on amd64 (64-bit platform and 4K pages) * 7 bits on i386 (32-bit platform and 4K pages) * 7 bits on sparc64 in 64-bit mode (8K pages) * 8 bits on sparc64 in 32-bit mode (8K pages) */ if (preallocate == -1) { switch (ngx_pagesize / sizeof(ngx_radix_node_t)) { /* amd64 */ case 128: preallocate = 6; break; /* i386, sparc64 */ case 256: preallocate = 7; break; /* sparc64 in 32-bit mode */ default: preallocate = 8; } } mask = 0; inc = 0x80000000; while (preallocate--) { key = 0; mask >>= 1; mask |= 0x80000000; do { if (ngx_radix32tree_insert(tree, key, mask, NGX_RADIX_NO_VALUE) != NGX_OK) { return NULL; } key += inc; } while (key); inc >>= 1; } return tree; } ngx_int_t ngx_radix32tree_insert(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask, uintptr_t value) { uint32_t bit; ngx_radix_node_t *node, *next; bit = 0x80000000; node = tree->root; next = tree->root; while (bit & mask) { if (key & bit) { next = node->right; } else { next = node->left; } if (next == NULL) { break; } bit >>= 1; node = next; } if (next) { if (node->value != NGX_RADIX_NO_VALUE) { return NGX_BUSY; } node->value = value; return NGX_OK; } while (bit & mask) { next = ngx_radix_alloc(tree); if (next == NULL) { return NGX_ERROR; } next->right = NULL; next->left = NULL; next->parent = node; next->value = NGX_RADIX_NO_VALUE; if (key & bit) { node->right = next; } else { node->left = next; } bit >>= 1; node = next; } node->value = value; return NGX_OK; } ngx_int_t ngx_radix32tree_delete(ngx_radix_tree_t *tree, uint32_t key, uint32_t mask) { uint32_t bit; ngx_radix_node_t *node; bit = 0x80000000; node = tree->root; while (node && (bit & mask)) { if (key & bit) { node = node->right; } else { node = node->left; } bit >>= 1; } if (node == NULL) { return NGX_ERROR; } if (node->right || node->left) { if (node->value != NGX_RADIX_NO_VALUE) { node->value = NGX_RADIX_NO_VALUE; return NGX_OK; } return NGX_ERROR; } for ( ;; ) { if (node->parent->right == node) { node->parent->right = NULL; } else { node->parent->left = NULL; } node->right = tree->free; tree->free = node; node = node->parent; if (node->right || node->left) { break; } if (node->value != NGX_RADIX_NO_VALUE) { break; } if (node->parent == NULL) { break; } } return NGX_OK; } uintptr_t ngx_radix32tree_find(ngx_radix_tree_t *tree, uint32_t key) { uint32_t bit; uintptr_t value; ngx_radix_node_t *node; bit = 0x80000000; value = NGX_RADIX_NO_VALUE; node = tree->root; while (node) { if (node->value != NGX_RADIX_NO_VALUE) { value = node->value; } if (key & bit) { node = node->right; } else { node = node->left; } bit >>= 1; } return value; } #if (NGX_HAVE_INET6) ngx_int_t ngx_radix128tree_insert(ngx_radix_tree_t *tree, u_char *key, u_char *mask, uintptr_t value) { u_char bit; ngx_uint_t i; ngx_radix_node_t *node, *next; i = 0; bit = 0x80; node = tree->root; next = tree->root; while (bit & mask[i]) { if (key[i] & bit) { next = node->right; } else { next = node->left; } if (next == NULL) { break; } bit >>= 1; node = next; if (bit == 0) { if (++i == 16) { break; } bit = 0x80; } } if (next) { if (node->value != NGX_RADIX_NO_VALUE) { return NGX_BUSY; } node->value = value; return NGX_OK; } while (bit & mask[i]) { next = ngx_radix_alloc(tree); if (next == NULL) { return NGX_ERROR; } next->right = NULL; next->left = NULL; next->parent = node; next->value = NGX_RADIX_NO_VALUE; if (key[i] & bit) { node->right = next; } else { node->left = next; } bit >>= 1; node = next; if (bit == 0) { if (++i == 16) { break; } bit = 0x80; } } node->value = value; return NGX_OK; } ngx_int_t ngx_radix128tree_delete(ngx_radix_tree_t *tree, u_char *key, u_char *mask) { u_char bit; ngx_uint_t i; ngx_radix_node_t *node; i = 0; bit = 0x80; node = tree->root; while (node && (bit & mask[i])) { if (key[i] & bit) { node = node->right; } else { node = node->left; } bit >>= 1; if (bit == 0) { if (++i == 16) { break; } bit = 0x80; } } if (node == NULL) { return NGX_ERROR; } if (node->right || node->left) { if (node->value != NGX_RADIX_NO_VALUE) { node->value = NGX_RADIX_NO_VALUE; return NGX_OK; } return NGX_ERROR; } for ( ;; ) { if (node->parent->right == node) { node->parent->right = NULL; } else { node->parent->left = NULL; } node->right = tree->free; tree->free = node; node = node->parent; if (node->right || node->left) { break; } if (node->value != NGX_RADIX_NO_VALUE) { break; } if (node->parent == NULL) { break; } } return NGX_OK; } uintptr_t ngx_radix128tree_find(ngx_radix_tree_t *tree, u_char *key) { u_char bit; uintptr_t value; ngx_uint_t i; ngx_radix_node_t *node; i = 0; bit = 0x80; value = NGX_RADIX_NO_VALUE; node = tree->root; while (node) { if (node->value != NGX_RADIX_NO_VALUE) { value = node->value; } if (key[i] & bit) { node = node->right; } else { node = node->left; } bit >>= 1; if (bit == 0) { i++; bit = 0x80; } } return value; } #endif static ngx_radix_node_t * ngx_radix_alloc(ngx_radix_tree_t *tree) { ngx_radix_node_t *p; if (tree->free) { p = tree->free; tree->free = tree->free->right; return p; } if (tree->size < sizeof(ngx_radix_node_t)) { tree->start = ngx_pmemalign(tree->pool, ngx_pagesize, ngx_pagesize); if (tree->start == NULL) { return NULL; } tree->size = ngx_pagesize; } p = (ngx_radix_node_t *) tree->start; tree->start += sizeof(ngx_radix_node_t); tree->size -= sizeof(ngx_radix_node_t); return p; }