From 2fc3fc0bcdcc5429947d1e5ed8f6f0a77ba80997 Mon Sep 17 00:00:00 2001 From: Andrii Nakryiko Date: Fri, 24 May 2019 11:59:02 -0700 Subject: [PATCH] libbpf: switch btf_dedup() to hashmap for dedup table Utilize libbpf's hashmap as a multimap fof dedup_table implementation. Signed-off-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov --- tools/lib/bpf/btf.c | 201 ++++++++++++++++++++++------------------------------ 1 file changed, 85 insertions(+), 116 deletions(-) diff --git a/tools/lib/bpf/btf.c b/tools/lib/bpf/btf.c index 6139550..b2478e9 100644 --- a/tools/lib/bpf/btf.c +++ b/tools/lib/bpf/btf.c @@ -14,6 +14,7 @@ #include "bpf.h" #include "libbpf.h" #include "libbpf_internal.h" +#include "hashmap.h" #define max(a, b) ((a) > (b) ? (a) : (b)) #define min(a, b) ((a) < (b) ? (a) : (b)) @@ -1293,16 +1294,9 @@ done: return err; } -#define BTF_DEDUP_TABLE_DEFAULT_SIZE (1 << 14) -#define BTF_DEDUP_TABLE_MAX_SIZE_LOG 31 #define BTF_UNPROCESSED_ID ((__u32)-1) #define BTF_IN_PROGRESS_ID ((__u32)-2) -struct btf_dedup_node { - struct btf_dedup_node *next; - __u32 type_id; -}; - struct btf_dedup { /* .BTF section to be deduped in-place */ struct btf *btf; @@ -1318,7 +1312,7 @@ struct btf_dedup { * candidates, which is fine because we rely on subsequent * btf_xxx_equal() checks to authoritatively verify type equality. */ - struct btf_dedup_node **dedup_table; + struct hashmap *dedup_table; /* Canonical types map */ __u32 *map; /* Hypothetical mapping, used during type graph equivalence checks */ @@ -1343,30 +1337,18 @@ struct btf_str_ptrs { __u32 cap; }; -static inline __u32 hash_combine(__u32 h, __u32 value) +static long hash_combine(long h, long value) { -/* 2^31 + 2^29 - 2^25 + 2^22 - 2^19 - 2^16 + 1 */ -#define GOLDEN_RATIO_PRIME 0x9e370001UL - return h * 37 + value * GOLDEN_RATIO_PRIME; -#undef GOLDEN_RATIO_PRIME + return h * 31 + value; } -#define for_each_dedup_cand(d, hash, node) \ - for (node = d->dedup_table[hash & (d->opts.dedup_table_size - 1)]; \ - node; \ - node = node->next) +#define for_each_dedup_cand(d, node, hash) \ + hashmap__for_each_key_entry(d->dedup_table, node, (void *)hash) -static int btf_dedup_table_add(struct btf_dedup *d, __u32 hash, __u32 type_id) +static int btf_dedup_table_add(struct btf_dedup *d, long hash, __u32 type_id) { - struct btf_dedup_node *node = malloc(sizeof(struct btf_dedup_node)); - int bucket = hash & (d->opts.dedup_table_size - 1); - - if (!node) - return -ENOMEM; - node->type_id = type_id; - node->next = d->dedup_table[bucket]; - d->dedup_table[bucket] = node; - return 0; + return hashmap__append(d->dedup_table, + (void *)hash, (void *)(long)type_id); } static int btf_dedup_hypot_map_add(struct btf_dedup *d, @@ -1395,36 +1377,10 @@ static void btf_dedup_clear_hypot_map(struct btf_dedup *d) d->hypot_cnt = 0; } -static void btf_dedup_table_free(struct btf_dedup *d) -{ - struct btf_dedup_node *head, *tmp; - int i; - - if (!d->dedup_table) - return; - - for (i = 0; i < d->opts.dedup_table_size; i++) { - while (d->dedup_table[i]) { - tmp = d->dedup_table[i]; - d->dedup_table[i] = tmp->next; - free(tmp); - } - - head = d->dedup_table[i]; - while (head) { - tmp = head; - head = head->next; - free(tmp); - } - } - - free(d->dedup_table); - d->dedup_table = NULL; -} - static void btf_dedup_free(struct btf_dedup *d) { - btf_dedup_table_free(d); + hashmap__free(d->dedup_table); + d->dedup_table = NULL; free(d->map); d->map = NULL; @@ -1438,40 +1394,43 @@ static void btf_dedup_free(struct btf_dedup *d) free(d); } -/* Find closest power of two >= to size, capped at 2^max_size_log */ -static __u32 roundup_pow2_max(__u32 size, int max_size_log) +static size_t btf_dedup_identity_hash_fn(const void *key, void *ctx) { - int i; + return (size_t)key; +} - for (i = 0; i < max_size_log && (1U << i) < size; i++) - ; - return 1U << i; +static size_t btf_dedup_collision_hash_fn(const void *key, void *ctx) +{ + return 0; } +static bool btf_dedup_equal_fn(const void *k1, const void *k2, void *ctx) +{ + return k1 == k2; +} static struct btf_dedup *btf_dedup_new(struct btf *btf, struct btf_ext *btf_ext, const struct btf_dedup_opts *opts) { struct btf_dedup *d = calloc(1, sizeof(struct btf_dedup)); + hashmap_hash_fn hash_fn = btf_dedup_identity_hash_fn; int i, err = 0; - __u32 sz; if (!d) return ERR_PTR(-ENOMEM); d->opts.dont_resolve_fwds = opts && opts->dont_resolve_fwds; - sz = opts && opts->dedup_table_size ? opts->dedup_table_size - : BTF_DEDUP_TABLE_DEFAULT_SIZE; - sz = roundup_pow2_max(sz, BTF_DEDUP_TABLE_MAX_SIZE_LOG); - d->opts.dedup_table_size = sz; + /* dedup_table_size is now used only to force collisions in tests */ + if (opts && opts->dedup_table_size == 1) + hash_fn = btf_dedup_collision_hash_fn; d->btf = btf; d->btf_ext = btf_ext; - d->dedup_table = calloc(d->opts.dedup_table_size, - sizeof(struct btf_dedup_node *)); - if (!d->dedup_table) { - err = -ENOMEM; + d->dedup_table = hashmap__new(hash_fn, btf_dedup_equal_fn, NULL); + if (IS_ERR(d->dedup_table)) { + err = PTR_ERR(d->dedup_table); + d->dedup_table = NULL; goto done; } @@ -1790,9 +1749,9 @@ done: return err; } -static __u32 btf_hash_common(struct btf_type *t) +static long btf_hash_common(struct btf_type *t) { - __u32 h; + long h; h = hash_combine(0, t->name_off); h = hash_combine(h, t->info); @@ -1808,10 +1767,10 @@ static bool btf_equal_common(struct btf_type *t1, struct btf_type *t2) } /* Calculate type signature hash of INT. */ -static __u32 btf_hash_int(struct btf_type *t) +static long btf_hash_int(struct btf_type *t) { __u32 info = *(__u32 *)(t + 1); - __u32 h; + long h; h = btf_hash_common(t); h = hash_combine(h, info); @@ -1831,9 +1790,9 @@ static bool btf_equal_int(struct btf_type *t1, struct btf_type *t2) } /* Calculate type signature hash of ENUM. */ -static __u32 btf_hash_enum(struct btf_type *t) +static long btf_hash_enum(struct btf_type *t) { - __u32 h; + long h; /* don't hash vlen and enum members to support enum fwd resolving */ h = hash_combine(0, t->name_off); @@ -1885,11 +1844,11 @@ static bool btf_compat_enum(struct btf_type *t1, struct btf_type *t2) * as referenced type IDs equivalence is established separately during type * graph equivalence check algorithm. */ -static __u32 btf_hash_struct(struct btf_type *t) +static long btf_hash_struct(struct btf_type *t) { struct btf_member *member = (struct btf_member *)(t + 1); __u32 vlen = BTF_INFO_VLEN(t->info); - __u32 h = btf_hash_common(t); + long h = btf_hash_common(t); int i; for (i = 0; i < vlen; i++) { @@ -1932,10 +1891,10 @@ static bool btf_shallow_equal_struct(struct btf_type *t1, struct btf_type *t2) * under assumption that they were already resolved to canonical type IDs and * are not going to change. */ -static __u32 btf_hash_array(struct btf_type *t) +static long btf_hash_array(struct btf_type *t) { struct btf_array *info = (struct btf_array *)(t + 1); - __u32 h = btf_hash_common(t); + long h = btf_hash_common(t); h = hash_combine(h, info->type); h = hash_combine(h, info->index_type); @@ -1986,11 +1945,11 @@ static bool btf_compat_array(struct btf_type *t1, struct btf_type *t2) * under assumption that they were already resolved to canonical type IDs and * are not going to change. */ -static inline __u32 btf_hash_fnproto(struct btf_type *t) +static long btf_hash_fnproto(struct btf_type *t) { struct btf_param *member = (struct btf_param *)(t + 1); __u16 vlen = BTF_INFO_VLEN(t->info); - __u32 h = btf_hash_common(t); + long h = btf_hash_common(t); int i; for (i = 0; i < vlen; i++) { @@ -2008,7 +1967,7 @@ static inline __u32 btf_hash_fnproto(struct btf_type *t) * This function is called during reference types deduplication to compare * FUNC_PROTO to potential canonical representative. */ -static inline bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) +static bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) { struct btf_param *m1, *m2; __u16 vlen; @@ -2034,7 +1993,7 @@ static inline bool btf_equal_fnproto(struct btf_type *t1, struct btf_type *t2) * IDs. This check is performed during type graph equivalence check and * referenced types equivalence is checked separately. */ -static inline bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) +static bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) { struct btf_param *m1, *m2; __u16 vlen; @@ -2065,11 +2024,12 @@ static inline bool btf_compat_fnproto(struct btf_type *t1, struct btf_type *t2) static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) { struct btf_type *t = d->btf->types[type_id]; + struct hashmap_entry *hash_entry; struct btf_type *cand; - struct btf_dedup_node *cand_node; /* if we don't find equivalent type, then we are canonical */ __u32 new_id = type_id; - __u32 h; + __u32 cand_id; + long h; switch (BTF_INFO_KIND(t->info)) { case BTF_KIND_CONST: @@ -2088,10 +2048,11 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_INT: h = btf_hash_int(t); - for_each_dedup_cand(d, h, cand_node) { - cand = d->btf->types[cand_node->type_id]; + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = d->btf->types[cand_id]; if (btf_equal_int(t, cand)) { - new_id = cand_node->type_id; + new_id = cand_id; break; } } @@ -2099,10 +2060,11 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) case BTF_KIND_ENUM: h = btf_hash_enum(t); - for_each_dedup_cand(d, h, cand_node) { - cand = d->btf->types[cand_node->type_id]; + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = d->btf->types[cand_id]; if (btf_equal_enum(t, cand)) { - new_id = cand_node->type_id; + new_id = cand_id; break; } if (d->opts.dont_resolve_fwds) @@ -2110,21 +2072,22 @@ static int btf_dedup_prim_type(struct btf_dedup *d, __u32 type_id) if (btf_compat_enum(t, cand)) { if (btf_is_enum_fwd(t)) { /* resolve fwd to full enum */ - new_id = cand_node->type_id; + new_id = cand_id; break; } /* resolve canonical enum fwd to full enum */ - d->map[cand_node->type_id] = type_id; + d->map[cand_id] = type_id; } } break; case BTF_KIND_FWD: h = btf_hash_common(t); - for_each_dedup_cand(d, h, cand_node) { - cand = d->btf->types[cand_node->type_id]; + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = d->btf->types[cand_id]; if (btf_equal_common(t, cand)) { - new_id = cand_node->type_id; + new_id = cand_id; break; } } @@ -2525,12 +2488,12 @@ static void btf_dedup_merge_hypot_map(struct btf_dedup *d) */ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) { - struct btf_dedup_node *cand_node; struct btf_type *cand_type, *t; + struct hashmap_entry *hash_entry; /* if we don't find equivalent type, then we are canonical */ __u32 new_id = type_id; __u16 kind; - __u32 h; + long h; /* already deduped or is in process of deduping (loop detected) */ if (d->map[type_id] <= BTF_MAX_NR_TYPES) @@ -2543,7 +2506,8 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) return 0; h = btf_hash_struct(t); - for_each_dedup_cand(d, h, cand_node) { + for_each_dedup_cand(d, hash_entry, h) { + __u32 cand_id = (__u32)(long)hash_entry->value; int eq; /* @@ -2556,17 +2520,17 @@ static int btf_dedup_struct_type(struct btf_dedup *d, __u32 type_id) * creating a loop (FWD -> STRUCT and STRUCT -> FWD), because * FWD and compatible STRUCT/UNION are considered equivalent. */ - cand_type = d->btf->types[cand_node->type_id]; + cand_type = d->btf->types[cand_id]; if (!btf_shallow_equal_struct(t, cand_type)) continue; btf_dedup_clear_hypot_map(d); - eq = btf_dedup_is_equiv(d, type_id, cand_node->type_id); + eq = btf_dedup_is_equiv(d, type_id, cand_id); if (eq < 0) return eq; if (!eq) continue; - new_id = cand_node->type_id; + new_id = cand_id; btf_dedup_merge_hypot_map(d); break; } @@ -2616,12 +2580,12 @@ static int btf_dedup_struct_types(struct btf_dedup *d) */ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) { - struct btf_dedup_node *cand_node; + struct hashmap_entry *hash_entry; + __u32 new_id = type_id, cand_id; struct btf_type *t, *cand; /* if we don't find equivalent type, then we are representative type */ - __u32 new_id = type_id; int ref_type_id; - __u32 h; + long h; if (d->map[type_id] == BTF_IN_PROGRESS_ID) return -ELOOP; @@ -2644,10 +2608,11 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) t->type = ref_type_id; h = btf_hash_common(t); - for_each_dedup_cand(d, h, cand_node) { - cand = d->btf->types[cand_node->type_id]; + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = d->btf->types[cand_id]; if (btf_equal_common(t, cand)) { - new_id = cand_node->type_id; + new_id = cand_id; break; } } @@ -2667,10 +2632,11 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) info->index_type = ref_type_id; h = btf_hash_array(t); - for_each_dedup_cand(d, h, cand_node) { - cand = d->btf->types[cand_node->type_id]; + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = d->btf->types[cand_id]; if (btf_equal_array(t, cand)) { - new_id = cand_node->type_id; + new_id = cand_id; break; } } @@ -2698,10 +2664,11 @@ static int btf_dedup_ref_type(struct btf_dedup *d, __u32 type_id) } h = btf_hash_fnproto(t); - for_each_dedup_cand(d, h, cand_node) { - cand = d->btf->types[cand_node->type_id]; + for_each_dedup_cand(d, hash_entry, h) { + cand_id = (__u32)(long)hash_entry->value; + cand = d->btf->types[cand_id]; if (btf_equal_fnproto(t, cand)) { - new_id = cand_node->type_id; + new_id = cand_id; break; } } @@ -2728,7 +2695,9 @@ static int btf_dedup_ref_types(struct btf_dedup *d) if (err < 0) return err; } - btf_dedup_table_free(d); + /* we won't need d->dedup_table anymore */ + hashmap__free(d->dedup_table); + d->dedup_table = NULL; return 0; } -- 2.7.4