477 lines
13 KiB
Diff
477 lines
13 KiB
Diff
From b1161e911d8edf2a5235b8419886018ff4ee0d64 Mon Sep 17 00:00:00 2001
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From: Andrii Nakryiko <andriin@fb.com>
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Date: Fri, 24 May 2019 11:59:00 -0700
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Subject: [PATCH 013/201] libbpf: add resizable non-thread safe internal
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hashmap
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mainline inclusion
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from mainline-v5.3-rc1
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commit e3b924224028c6fc31545e3812eecbe2ddbf35f6
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category: feature
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bugzilla: https://gitee.com/openeuler/kernel/issues/I8C0CX
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Reference: https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=e3b924224028c6fc31545e3812eecbe2ddbf35f6
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----------------------------------------------------------------------
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There is a need for fast point lookups inside libbpf for multiple use
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cases (e.g., name resolution for BTF-to-C conversion, by-name lookups in
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BTF for upcoming BPF CO-RE relocation support, etc). This patch
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implements simple resizable non-thread safe hashmap using single linked
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list chains.
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Four different insert strategies are supported:
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- HASHMAP_ADD - only add key/value if key doesn't exist yet;
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- HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
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update value;
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- HASHMAP_UPDATE - update value, if key already exists; otherwise, do
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nothing and return -ENOENT;
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- HASHMAP_APPEND - always add key/value pair, even if key already exists.
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This turns hashmap into a multimap by allowing multiple values to be
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associated with the same key. Most useful read API for such hashmap is
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hashmap__for_each_key_entry() iteration. If hashmap__find() is still
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used, it will return last inserted key/value entry (first in a bucket
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chain).
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For HASHMAP_SET and HASHMAP_UPDATE, old key/value pair is returned, so
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that calling code can handle proper memory management, if necessary.
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Signed-off-by: Andrii Nakryiko <andriin@fb.com>
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Signed-off-by: Alexei Starovoitov <ast@kernel.org>
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Signed-off-by: hongrongxuan <hongrongxuan@huawei.com>
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Conflicts:
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tools/lib/bpf/Build
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tools/lib/bpf/hashmap.h
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---
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tools/lib/bpf/Build | 2 +-
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tools/lib/bpf/hashmap.c | 229 ++++++++++++++++++++++++++++++++++++++++
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tools/lib/bpf/hashmap.h | 172 ++++++++++++++++++++++++++++++
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3 files changed, 402 insertions(+), 1 deletion(-)
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create mode 100644 tools/lib/bpf/hashmap.c
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create mode 100644 tools/lib/bpf/hashmap.h
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diff --git a/tools/lib/bpf/Build b/tools/lib/bpf/Build
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index 6eb9bacd1948..3e993bf724db 100644
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--- a/tools/lib/bpf/Build
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+++ b/tools/lib/bpf/Build
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@@ -1 +1 @@
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-libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o
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+libbpf-y := libbpf.o bpf.o nlattr.o btf.o libbpf_errno.o str_error.o hashmap.o
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diff --git a/tools/lib/bpf/hashmap.c b/tools/lib/bpf/hashmap.c
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new file mode 100644
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index 000000000000..6122272943e6
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--- /dev/null
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+++ b/tools/lib/bpf/hashmap.c
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@@ -0,0 +1,229 @@
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+// SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause)
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+
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+/*
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+ * Generic non-thread safe hash map implementation.
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+ *
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+ * Copyright (c) 2019 Facebook
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+ */
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+#include <stdint.h>
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+#include <stdlib.h>
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+#include <stdio.h>
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+#include <errno.h>
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+#include <linux/err.h>
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+#include "hashmap.h"
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+
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+/* start with 4 buckets */
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+#define HASHMAP_MIN_CAP_BITS 2
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+
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+static void hashmap_add_entry(struct hashmap_entry **pprev,
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+ struct hashmap_entry *entry)
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+{
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+ entry->next = *pprev;
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+ *pprev = entry;
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+}
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+
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+static void hashmap_del_entry(struct hashmap_entry **pprev,
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+ struct hashmap_entry *entry)
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+{
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+ *pprev = entry->next;
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+ entry->next = NULL;
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+}
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+
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+void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
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+ hashmap_equal_fn equal_fn, void *ctx)
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+{
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+ map->hash_fn = hash_fn;
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+ map->equal_fn = equal_fn;
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+ map->ctx = ctx;
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+
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+ map->buckets = NULL;
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+ map->cap = 0;
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+ map->cap_bits = 0;
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+ map->sz = 0;
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+}
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+
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+struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
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+ hashmap_equal_fn equal_fn,
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+ void *ctx)
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+{
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+ struct hashmap *map = malloc(sizeof(struct hashmap));
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+
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+ if (!map)
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+ return ERR_PTR(-ENOMEM);
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+ hashmap__init(map, hash_fn, equal_fn, ctx);
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+ return map;
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+}
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+
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+void hashmap__clear(struct hashmap *map)
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+{
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+ free(map->buckets);
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+ map->cap = map->cap_bits = map->sz = 0;
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+}
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+
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+void hashmap__free(struct hashmap *map)
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+{
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+ if (!map)
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+ return;
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+
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+ hashmap__clear(map);
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+ free(map);
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+}
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+
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+size_t hashmap__size(const struct hashmap *map)
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+{
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+ return map->sz;
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+}
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+
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+size_t hashmap__capacity(const struct hashmap *map)
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+{
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+ return map->cap;
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+}
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+
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+static bool hashmap_needs_to_grow(struct hashmap *map)
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+{
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+ /* grow if empty or more than 75% filled */
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+ return (map->cap == 0) || ((map->sz + 1) * 4 / 3 > map->cap);
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+}
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+
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+static int hashmap_grow(struct hashmap *map)
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+{
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+ struct hashmap_entry **new_buckets;
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+ struct hashmap_entry *cur, *tmp;
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+ size_t new_cap_bits, new_cap;
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+ size_t h;
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+ int bkt;
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+
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+ new_cap_bits = map->cap_bits + 1;
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+ if (new_cap_bits < HASHMAP_MIN_CAP_BITS)
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+ new_cap_bits = HASHMAP_MIN_CAP_BITS;
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+
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+ new_cap = 1UL << new_cap_bits;
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+ new_buckets = calloc(new_cap, sizeof(new_buckets[0]));
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+ if (!new_buckets)
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+ return -ENOMEM;
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+
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+ hashmap__for_each_entry_safe(map, cur, tmp, bkt) {
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+ h = hash_bits(map->hash_fn(cur->key, map->ctx), new_cap_bits);
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+ hashmap_add_entry(&new_buckets[h], cur);
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+ }
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+
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+ map->cap = new_cap;
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+ map->cap_bits = new_cap_bits;
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+ free(map->buckets);
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+ map->buckets = new_buckets;
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+
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+ return 0;
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+}
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+
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+static bool hashmap_find_entry(const struct hashmap *map,
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+ const void *key, size_t hash,
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+ struct hashmap_entry ***pprev,
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+ struct hashmap_entry **entry)
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+{
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+ struct hashmap_entry *cur, **prev_ptr;
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+
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+ if (!map->buckets)
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+ return false;
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+
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+ for (prev_ptr = &map->buckets[hash], cur = *prev_ptr;
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+ cur;
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+ prev_ptr = &cur->next, cur = cur->next) {
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+ if (map->equal_fn(cur->key, key, map->ctx)) {
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+ if (pprev)
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+ *pprev = prev_ptr;
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+ *entry = cur;
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+ return true;
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+ }
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+ }
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+
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+ return false;
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+}
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+
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+int hashmap__insert(struct hashmap *map, const void *key, void *value,
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+ enum hashmap_insert_strategy strategy,
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+ const void **old_key, void **old_value)
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+{
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+ struct hashmap_entry *entry;
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+ size_t h;
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+ int err;
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+
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+ if (old_key)
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+ *old_key = NULL;
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+ if (old_value)
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+ *old_value = NULL;
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+
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+ h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
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+ if (strategy != HASHMAP_APPEND &&
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+ hashmap_find_entry(map, key, h, NULL, &entry)) {
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+ if (old_key)
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+ *old_key = entry->key;
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+ if (old_value)
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+ *old_value = entry->value;
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+
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+ if (strategy == HASHMAP_SET || strategy == HASHMAP_UPDATE) {
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+ entry->key = key;
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+ entry->value = value;
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+ return 0;
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+ } else if (strategy == HASHMAP_ADD) {
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+ return -EEXIST;
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+ }
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+ }
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+
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+ if (strategy == HASHMAP_UPDATE)
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+ return -ENOENT;
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+
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+ if (hashmap_needs_to_grow(map)) {
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+ err = hashmap_grow(map);
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+ if (err)
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+ return err;
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+ h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
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+ }
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+
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+ entry = malloc(sizeof(struct hashmap_entry));
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+ if (!entry)
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+ return -ENOMEM;
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+
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+ entry->key = key;
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+ entry->value = value;
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+ hashmap_add_entry(&map->buckets[h], entry);
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+ map->sz++;
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+
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+ return 0;
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+}
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+
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+bool hashmap__find(const struct hashmap *map, const void *key, void **value)
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+{
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+ struct hashmap_entry *entry;
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+ size_t h;
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+
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+ h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
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+ if (!hashmap_find_entry(map, key, h, NULL, &entry))
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+ return false;
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+
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+ if (value)
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+ *value = entry->value;
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+ return true;
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+}
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+
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+bool hashmap__delete(struct hashmap *map, const void *key,
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+ const void **old_key, void **old_value)
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+{
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+ struct hashmap_entry **pprev, *entry;
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+ size_t h;
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+
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+ h = hash_bits(map->hash_fn(key, map->ctx), map->cap_bits);
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+ if (!hashmap_find_entry(map, key, h, &pprev, &entry))
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+ return false;
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+
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+ if (old_key)
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+ *old_key = entry->key;
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+ if (old_value)
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+ *old_value = entry->value;
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+
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+ hashmap_del_entry(pprev, entry);
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+ free(entry);
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+ map->sz--;
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+
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+ return true;
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+}
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+
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diff --git a/tools/lib/bpf/hashmap.h b/tools/lib/bpf/hashmap.h
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new file mode 100644
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index 000000000000..ab97b9797100
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--- /dev/null
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+++ b/tools/lib/bpf/hashmap.h
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@@ -0,0 +1,172 @@
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+/* SPDX-License-Identifier: (LGPL-2.1 OR BSD-2-Clause) */
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+
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+/*
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+ * Generic non-thread safe hash map implementation.
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+ *
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+ * Copyright (c) 2019 Facebook
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+ */
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+#ifndef __LIBBPF_HASHMAP_H
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+#define __LIBBPF_HASHMAP_H
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+
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+#include <stdbool.h>
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+#include <stddef.h>
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+
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+static inline size_t hash_bits(size_t h, int bits)
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+{
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+ /* shuffle bits and return requested number of upper bits */
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+ return (h * 11400714819323198485llu) >> (__WORDSIZE - bits);
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+}
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+
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+typedef size_t (*hashmap_hash_fn)(const void *key, void *ctx);
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+typedef bool (*hashmap_equal_fn)(const void *key1, const void *key2, void *ctx);
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+
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+struct hashmap_entry {
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+ const void *key;
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+ void *value;
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+ struct hashmap_entry *next;
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+};
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+
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+struct hashmap {
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+ hashmap_hash_fn hash_fn;
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+ hashmap_equal_fn equal_fn;
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+ void *ctx;
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+
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+ struct hashmap_entry **buckets;
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+ size_t cap;
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+ size_t cap_bits;
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+ size_t sz;
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+};
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+
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+#define HASHMAP_INIT(hash_fn, equal_fn, ctx) { \
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+ .hash_fn = (hash_fn), \
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+ .equal_fn = (equal_fn), \
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+ .ctx = (ctx), \
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+ .buckets = NULL, \
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+ .cap = 0, \
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+ .cap_bits = 0, \
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+ .sz = 0, \
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+}
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+
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+void hashmap__init(struct hashmap *map, hashmap_hash_fn hash_fn,
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+ hashmap_equal_fn equal_fn, void *ctx);
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+struct hashmap *hashmap__new(hashmap_hash_fn hash_fn,
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+ hashmap_equal_fn equal_fn,
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+ void *ctx);
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+void hashmap__clear(struct hashmap *map);
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+void hashmap__free(struct hashmap *map);
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+
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+size_t hashmap__size(const struct hashmap *map);
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+size_t hashmap__capacity(const struct hashmap *map);
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+
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+/*
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+ * Hashmap insertion strategy:
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+ * - HASHMAP_ADD - only add key/value if key doesn't exist yet;
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+ * - HASHMAP_SET - add key/value pair if key doesn't exist yet; otherwise,
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+ * update value;
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+ * - HASHMAP_UPDATE - update value, if key already exists; otherwise, do
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+ * nothing and return -ENOENT;
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+ * - HASHMAP_APPEND - always add key/value pair, even if key already exists.
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+ * This turns hashmap into a multimap by allowing multiple values to be
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+ * associated with the same key. Most useful read API for such hashmap is
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+ * hashmap__for_each_key_entry() iteration. If hashmap__find() is still
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+ * used, it will return last inserted key/value entry (first in a bucket
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+ * chain).
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+ */
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+enum hashmap_insert_strategy {
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+ HASHMAP_ADD,
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+ HASHMAP_SET,
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+ HASHMAP_UPDATE,
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+ HASHMAP_APPEND,
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+};
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+
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+/*
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+ * hashmap__insert() adds key/value entry w/ various semantics, depending on
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+ * provided strategy value. If a given key/value pair replaced already
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+ * existing key/value pair, both old key and old value will be returned
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+ * through old_key and old_value to allow calling code do proper memory
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+ * management.
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+ */
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+int hashmap__insert(struct hashmap *map, const void *key, void *value,
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+ enum hashmap_insert_strategy strategy,
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+ const void **old_key, void **old_value);
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+
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+static inline int hashmap__add(struct hashmap *map,
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+ const void *key, void *value)
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+{
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+ return hashmap__insert(map, key, value, HASHMAP_ADD, NULL, NULL);
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+}
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+
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+static inline int hashmap__set(struct hashmap *map,
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+ const void *key, void *value,
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+ const void **old_key, void **old_value)
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+{
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+ return hashmap__insert(map, key, value, HASHMAP_SET,
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+ old_key, old_value);
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+}
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+
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+static inline int hashmap__update(struct hashmap *map,
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+ const void *key, void *value,
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+ const void **old_key, void **old_value)
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+{
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+ return hashmap__insert(map, key, value, HASHMAP_UPDATE,
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+ old_key, old_value);
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+}
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+
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+static inline int hashmap__append(struct hashmap *map,
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+ const void *key, void *value)
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+{
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+ return hashmap__insert(map, key, value, HASHMAP_APPEND, NULL, NULL);
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+}
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+
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+bool hashmap__delete(struct hashmap *map, const void *key,
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+ const void **old_key, void **old_value);
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+
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+bool hashmap__find(const struct hashmap *map, const void *key, void **value);
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+
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+/*
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+ * hashmap__for_each_entry - iterate over all entries in hashmap
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+ * @map: hashmap to iterate
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+ * @cur: struct hashmap_entry * used as a loop cursor
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+ * @bkt: integer used as a bucket loop cursor
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+ */
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+#define hashmap__for_each_entry(map, cur, bkt) \
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+ for (bkt = 0; bkt < map->cap; bkt++) \
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+ for (cur = map->buckets[bkt]; cur; cur = cur->next)
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+
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+/*
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+ * hashmap__for_each_entry_safe - iterate over all entries in hashmap, safe
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+ * against removals
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+ * @map: hashmap to iterate
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+ * @cur: struct hashmap_entry * used as a loop cursor
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+ * @tmp: struct hashmap_entry * used as a temporary next cursor storage
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+ * @bkt: integer used as a bucket loop cursor
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+ */
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+#define hashmap__for_each_entry_safe(map, cur, tmp, bkt) \
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+ for (bkt = 0; bkt < map->cap; bkt++) \
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+ for (cur = map->buckets[bkt]; \
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+ cur && ({tmp = cur->next; true; }); \
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+ cur = tmp)
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+
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+/*
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+ * hashmap__for_each_key_entry - iterate over entries associated with given key
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+ * @map: hashmap to iterate
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+ * @cur: struct hashmap_entry * used as a loop cursor
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+ * @key: key to iterate entries for
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+ */
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+#define hashmap__for_each_key_entry(map, cur, _key) \
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+ for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
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+ map->cap_bits); \
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+ map->buckets ? map->buckets[bkt] : NULL; }); \
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+ cur; \
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+ cur = cur->next) \
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+ if (map->equal_fn(cur->key, (_key), map->ctx))
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+
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+#define hashmap__for_each_key_entry_safe(map, cur, tmp, _key) \
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+ for (cur = ({ size_t bkt = hash_bits(map->hash_fn((_key), map->ctx),\
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+ map->cap_bits); \
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+ cur = map->buckets ? map->buckets[bkt] : NULL; }); \
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+ cur && ({ tmp = cur->next; true; }); \
|
|
+ cur = tmp) \
|
|
+ if (map->equal_fn(cur->key, (_key), map->ctx))
|
|
+
|
|
+#endif /* __LIBBPF_HASHMAP_H */
|
|
--
|
|
2.27.0
|
|
|