From patchwork Thu Sep 1 16:15:43 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 12962878 X-Patchwork-Delegate: bpf@iogearbox.net Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 67C5BECAAD3 for ; Thu, 1 Sep 2022 16:16:41 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S235036AbiIAQQj (ORCPT ); Thu, 1 Sep 2022 12:16:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:56686 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235032AbiIAQQg (ORCPT ); Thu, 1 Sep 2022 12:16:36 -0400 Received: from mail-pg1-x536.google.com (mail-pg1-x536.google.com [IPv6:2607:f8b0:4864:20::536]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 348775AA01 for ; Thu, 1 Sep 2022 09:16:33 -0700 (PDT) Received: by mail-pg1-x536.google.com with SMTP id r69so16834793pgr.2 for ; Thu, 01 Sep 2022 09:16:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc; bh=1exLg6zwiw8VbHVoGF/maqudTmvyPHhqAhRpXlF+ss0=; b=EQZ2xzNN/0pRofenn394iYwAnngKtYZO4PkW25lRchNBqSfY53KPDiiOeBvxvvZ2Sh BXUEvCBjiu+lAg197XopYD4oTFaLqlxN2KbfMtcm9MEw7/Eg6rV4HkYrEQ9GoSO0WsOd vTos5yTnDCE8oWBmdsFxcLg7RScP2U4/3XtIKyAiB9MeFUwkpEbg/cDA1JACSQhM5ZyT srhMbxha1n3ZpmbtIcA+Fj4/IZC/3k/Fe0hvO/kARSJLgzQ/1nCWuhgpGWplDoXAS8su wAqGbvqgvWdhXM9euXA/jQsxhCCpvlFNajxML4kHDMVMLSe7PqyEgvSFzK4dLUSOWDRj JocA== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20210112; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc; bh=1exLg6zwiw8VbHVoGF/maqudTmvyPHhqAhRpXlF+ss0=; b=fZiTdDEK6pDqTZ7wkC9yi6UQcNddy+pKifmuKLUrMgJp34MkWggA0T+uFxugd1kQFG 9XcTXFbPD1ynAULzjAj5V+MFT7mUXnp/yQTXSUXb8sfMtnZ4o/vvOCqioILPl9uPmK5e bRBO7UIHDPbSS+/0G3XXT2UtYBWaE8+3KcvTfdjScktYxTByCRfJDXAcv0Ot4zN9orlY BR49nj3uaKkOC/42Xo04SFAepf4kmc5Y/l9GIfocPHNMduZH6XtY+8OQQPl+Ru2TMojG aD1znHhTLMiFyz4Qsx6MolgbgKaA1Fmg5fM4vpzLeaZcwwKZ+rjCuCGQMwoJp6v3oM7g jTFg== X-Gm-Message-State: ACgBeo0O+802JGOyuBGiX0QI9Bj50S96phClhmV019WEnAOD0t2XtDvs eM9KeiHVSEVQiWjlPIiv05U= X-Google-Smtp-Source: AA6agR6stlm8Bfa1pY7zMhm7F5fF+hwY+KVk2t1NXgdhaVgBQk9p7W4bd5KMa4PGlvwVGZd0nkoPjA== X-Received: by 2002:a63:2a49:0:b0:41d:95d8:3d3d with SMTP id q70-20020a632a49000000b0041d95d83d3dmr26749135pgq.43.1662048992561; Thu, 01 Sep 2022 09:16:32 -0700 (PDT) Received: from localhost.localdomain ([2620:10d:c090:500::3:4dc5]) by smtp.gmail.com with ESMTPSA id 198-20020a6216cf000000b0052b84ca900csm13611271pfw.62.2022.09.01.09.16.31 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Thu, 01 Sep 2022 09:16:32 -0700 (PDT) From: Alexei Starovoitov To: davem@davemloft.net Cc: daniel@iogearbox.net, andrii@kernel.org, tj@kernel.org, memxor@gmail.com, delyank@fb.com, linux-mm@kvack.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v5 bpf-next 11/15] bpf: Convert percpu hash map to per-cpu bpf_mem_alloc. Date: Thu, 1 Sep 2022 09:15:43 -0700 Message-Id: <20220901161547.57722-12-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.36.1 In-Reply-To: <20220901161547.57722-1-alexei.starovoitov@gmail.com> References: <20220901161547.57722-1-alexei.starovoitov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org X-Patchwork-Delegate: bpf@iogearbox.net From: Alexei Starovoitov Convert dynamic allocations in percpu hash map from alloc_percpu() to bpf_mem_cache_alloc() from per-cpu bpf_mem_alloc. Since bpf_mem_alloc frees objects after RCU gp the call_rcu() is removed. pcpu_init_value() now needs to zero-fill per-cpu allocations, since dynamically allocated map elements are now similar to full prealloc, since alloc_percpu() is not called inline and the elements are reused in the freelist. Acked-by: Kumar Kartikeya Dwivedi Acked-by: Andrii Nakryiko Signed-off-by: Alexei Starovoitov --- kernel/bpf/hashtab.c | 45 +++++++++++++++++++------------------------- 1 file changed, 19 insertions(+), 26 deletions(-) diff --git a/kernel/bpf/hashtab.c b/kernel/bpf/hashtab.c index 70b02ff4445e..a77b9c4a4e48 100644 --- a/kernel/bpf/hashtab.c +++ b/kernel/bpf/hashtab.c @@ -94,6 +94,7 @@ struct bucket { struct bpf_htab { struct bpf_map map; struct bpf_mem_alloc ma; + struct bpf_mem_alloc pcpu_ma; struct bucket *buckets; void *elems; union { @@ -121,14 +122,14 @@ struct htab_elem { struct { void *padding; union { - struct bpf_htab *htab; struct pcpu_freelist_node fnode; struct htab_elem *batch_flink; }; }; }; union { - struct rcu_head rcu; + /* pointer to per-cpu pointer */ + void *ptr_to_pptr; struct bpf_lru_node lru_node; }; u32 hash; @@ -448,8 +449,6 @@ static int htab_map_alloc_check(union bpf_attr *attr) bool zero_seed = (attr->map_flags & BPF_F_ZERO_SEED); int numa_node = bpf_map_attr_numa_node(attr); - BUILD_BUG_ON(offsetof(struct htab_elem, htab) != - offsetof(struct htab_elem, hash_node.pprev)); BUILD_BUG_ON(offsetof(struct htab_elem, fnode.next) != offsetof(struct htab_elem, hash_node.pprev)); @@ -610,6 +609,12 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) err = bpf_mem_alloc_init(&htab->ma, htab->elem_size, false); if (err) goto free_map_locked; + if (percpu) { + err = bpf_mem_alloc_init(&htab->pcpu_ma, + round_up(htab->map.value_size, 8), true); + if (err) + goto free_map_locked; + } } return &htab->map; @@ -620,6 +625,7 @@ static struct bpf_map *htab_map_alloc(union bpf_attr *attr) for (i = 0; i < HASHTAB_MAP_LOCK_COUNT; i++) free_percpu(htab->map_locked[i]); bpf_map_area_free(htab->buckets); + bpf_mem_alloc_destroy(&htab->pcpu_ma); bpf_mem_alloc_destroy(&htab->ma); free_htab: lockdep_unregister_key(&htab->lockdep_key); @@ -895,19 +901,11 @@ static int htab_map_get_next_key(struct bpf_map *map, void *key, void *next_key) static void htab_elem_free(struct bpf_htab *htab, struct htab_elem *l) { if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) - free_percpu(htab_elem_get_ptr(l, htab->map.key_size)); + bpf_mem_cache_free(&htab->pcpu_ma, l->ptr_to_pptr); check_and_free_fields(htab, l); bpf_mem_cache_free(&htab->ma, l); } -static void htab_elem_free_rcu(struct rcu_head *head) -{ - struct htab_elem *l = container_of(head, struct htab_elem, rcu); - struct bpf_htab *htab = l->htab; - - htab_elem_free(htab, l); -} - static void htab_put_fd_value(struct bpf_htab *htab, struct htab_elem *l) { struct bpf_map *map = &htab->map; @@ -953,12 +951,7 @@ static void free_htab_elem(struct bpf_htab *htab, struct htab_elem *l) __pcpu_freelist_push(&htab->freelist, &l->fnode); } else { dec_elem_count(htab); - if (htab->map.map_type == BPF_MAP_TYPE_PERCPU_HASH) { - l->htab = htab; - call_rcu(&l->rcu, htab_elem_free_rcu); - } else { - htab_elem_free(htab, l); - } + htab_elem_free(htab, l); } } @@ -983,13 +976,12 @@ static void pcpu_copy_value(struct bpf_htab *htab, void __percpu *pptr, static void pcpu_init_value(struct bpf_htab *htab, void __percpu *pptr, void *value, bool onallcpus) { - /* When using prealloc and not setting the initial value on all cpus, - * zero-fill element values for other cpus (just as what happens when - * not using prealloc). Otherwise, bpf program has no way to ensure + /* When not setting the initial value on all cpus, zero-fill element + * values for other cpus. Otherwise, bpf program has no way to ensure * known initial values for cpus other than current one * (onallcpus=false always when coming from bpf prog). */ - if (htab_is_prealloc(htab) && !onallcpus) { + if (!onallcpus) { u32 size = round_up(htab->map.value_size, 8); int current_cpu = raw_smp_processor_id(); int cpu; @@ -1060,18 +1052,18 @@ static struct htab_elem *alloc_htab_elem(struct bpf_htab *htab, void *key, memcpy(l_new->key, key, key_size); if (percpu) { - size = round_up(size, 8); if (prealloc) { pptr = htab_elem_get_ptr(l_new, key_size); } else { /* alloc_percpu zero-fills */ - pptr = bpf_map_alloc_percpu(&htab->map, size, 8, - GFP_NOWAIT | __GFP_NOWARN); + pptr = bpf_mem_cache_alloc(&htab->pcpu_ma); if (!pptr) { bpf_mem_cache_free(&htab->ma, l_new); l_new = ERR_PTR(-ENOMEM); goto dec_count; } + l_new->ptr_to_pptr = pptr; + pptr = *(void **)pptr; } pcpu_init_value(htab, pptr, value, onallcpus); @@ -1568,6 +1560,7 @@ static void htab_map_free(struct bpf_map *map) bpf_map_free_kptr_off_tab(map); free_percpu(htab->extra_elems); bpf_map_area_free(htab->buckets); + bpf_mem_alloc_destroy(&htab->pcpu_ma); bpf_mem_alloc_destroy(&htab->ma); if (htab->use_percpu_counter) percpu_counter_destroy(&htab->pcount);