1 // SPDX-License-Identifier: GPL-2.0 2 /* Copyright (c) 2022 Meta Platforms, Inc. and affiliates. */ 3 4 #include "vmlinux.h" 5 #include <bpf/bpf_helpers.h> 6 #include "bpf_misc.h" 7 8 #define HASHMAP_SZ 4194304 9 10 struct { 11 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS); 12 __uint(max_entries, 1000); 13 __type(key, int); 14 __type(value, int); 15 __array(values, struct { 16 __uint(type, BPF_MAP_TYPE_TASK_STORAGE); 17 __uint(map_flags, BPF_F_NO_PREALLOC); 18 __type(key, int); 19 __type(value, int); 20 }); 21 } array_of_local_storage_maps SEC(".maps"); 22 23 struct { 24 __uint(type, BPF_MAP_TYPE_ARRAY_OF_MAPS); 25 __uint(max_entries, 1000); 26 __type(key, int); 27 __type(value, int); 28 __array(values, struct { 29 __uint(type, BPF_MAP_TYPE_HASH); 30 __uint(max_entries, HASHMAP_SZ); 31 __type(key, int); 32 __type(value, int); 33 }); 34 } array_of_hash_maps SEC(".maps"); 35 36 long important_hits; 37 long hits; 38 39 /* set from user-space */ 40 const volatile unsigned int use_hashmap; 41 const volatile unsigned int hashmap_num_keys; 42 const volatile unsigned int num_maps; 43 const volatile unsigned int interleave; 44 45 struct loop_ctx { 46 struct task_struct *task; 47 long loop_hits; 48 long loop_important_hits; 49 }; 50 51 static int do_lookup(unsigned int elem, struct loop_ctx *lctx) 52 { 53 void *map, *inner_map; 54 int idx = 0; 55 56 if (use_hashmap) 57 map = &array_of_hash_maps; 58 else 59 map = &array_of_local_storage_maps; 60 61 inner_map = bpf_map_lookup_elem(map, &elem); 62 if (!inner_map) 63 return -1; 64 65 if (use_hashmap) { 66 idx = bpf_get_prandom_u32() % hashmap_num_keys; 67 bpf_map_lookup_elem(inner_map, &idx); 68 } else { 69 bpf_task_storage_get(inner_map, lctx->task, &idx, 70 BPF_LOCAL_STORAGE_GET_F_CREATE); 71 } 72 73 lctx->loop_hits++; 74 if (!elem) 75 lctx->loop_important_hits++; 76 return 0; 77 } 78 79 static long loop(u32 index, void *ctx) 80 { 81 struct loop_ctx *lctx = (struct loop_ctx *)ctx; 82 unsigned int map_idx = index % num_maps; 83 84 do_lookup(map_idx, lctx); 85 if (interleave && map_idx % 3 == 0) 86 do_lookup(0, lctx); 87 return 0; 88 } 89 90 SEC("fentry/" SYS_PREFIX "sys_getpgid") 91 int get_local(void *ctx) 92 { 93 struct loop_ctx lctx; 94 95 lctx.task = bpf_get_current_task_btf(); 96 lctx.loop_hits = 0; 97 lctx.loop_important_hits = 0; 98 bpf_loop(10000, &loop, &lctx, 0); 99 __sync_add_and_fetch(&hits, lctx.loop_hits); 100 __sync_add_and_fetch(&important_hits, lctx.loop_important_hits); 101 return 0; 102 } 103 104 char _license[] SEC("license") = "GPL"; 105