From patchwork Sat Jun 24 03:13:26 2023 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Alexei Starovoitov X-Patchwork-Id: 13291585 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 37A1FEB64DA for ; Sat, 24 Jun 2023 03:14:05 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229653AbjFXDOE (ORCPT ); Fri, 23 Jun 2023 23:14:04 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:43798 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229493AbjFXDOC (ORCPT ); Fri, 23 Jun 2023 23:14:02 -0400 Received: from mail-pf1-x42d.google.com (mail-pf1-x42d.google.com [IPv6:2607:f8b0:4864:20::42d]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 34DD3E47; Fri, 23 Jun 2023 20:14:01 -0700 (PDT) Received: by mail-pf1-x42d.google.com with SMTP id d2e1a72fcca58-666edfc50deso953958b3a.0; Fri, 23 Jun 2023 20:14:01 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20221208; t=1687576440; x=1690168440; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:from:to:cc:subject:date :message-id:reply-to; bh=6NzUeillbcneAmPlmWD6PS2VoyHI/+zawYBd3/Cla9Q=; b=WOvB2DoFrcCtkYpdzTee0UfRcZ88G3EyFMnIdQ/OfGfpioFFt2EI0pHnOK8QDFQcUn 3CG002jvQgYcUtr4Wrkh269r8u+IMXFq6wpIrmUZ9lSG0DqhZVLPs1dn54JXHcNprfg+ uQ4M269JQLLQLl5nuKBZzrov6FfiLdVmm9OXURYEC4q0kaAQCNWusoJuJEej2OYGs7g5 sth4AvvSdZAisNZQjCDt9qzzVnJ2vrSFYrcT72zI88US1IPfinnit68ayqcCs0jWRNhN GGfdY8Qeg67KH6Z6V7o/3BxM1EQ5zHCCTplTcwimq33KENvOy+lOBhyrjFN0qSBiNICT 9EtQ== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1687576440; x=1690168440; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:date:subject:cc:to:from:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=6NzUeillbcneAmPlmWD6PS2VoyHI/+zawYBd3/Cla9Q=; b=MS4lJuKPxO3OlCKYkMhs1vIpXa3PUBWzwJ+zMZZHVcMZSNj8nbXW52woqfD0hhshB2 jKe6gC3zqii9mBmLV10ijTQ4/Os75jMBCe/VZyDuEf/iKDPT7YzH7lVX4WV4gjCFGghP Ea2C+JIYh2flvO7pUtO07jZlhDjEBUev7a+zMnjTOj9V4N3CKRi/LuttWgnEJ8qJQA2V uC4FrwCrfqktph0Uu0sjVXibiwZSMcQdRCnw7YG1IbU4dZ0V7ZdhLnMCun1U+0f8ibdx JNv/PtvQfqZkNhgalSyaKCQAekMCGGGrrSQSGUyV7qy52RbtWhaaoqtZIbxYNaQdxuB0 yrUA== X-Gm-Message-State: AC+VfDz6sLwxbLIS+G8lVkh9y7ogExm9BW7QsIpjjFJm4y8XI1fsEuPJ b1bV/PSOAe5FHn0/2NYhsnY= X-Google-Smtp-Source: ACHHUZ6YBhluqOiTsx34LSBcnnY9tu+ylZF2DnVSdPaVCqp5S44vjjm8wFeoE6xwEJObVsQtwoUJew== X-Received: by 2002:a05:6a00:e85:b0:666:6c01:2e9e with SMTP id bo5-20020a056a000e8500b006666c012e9emr31798591pfb.15.1687576440512; Fri, 23 Jun 2023 20:14:00 -0700 (PDT) Received: from localhost.localdomain ([2620:10d:c090:400::5:b07c]) by smtp.gmail.com with ESMTPSA id 16-20020a630f50000000b00553c09cc795sm318137pgp.50.2023.06.23.20.13.58 (version=TLS1_3 cipher=TLS_CHACHA20_POLY1305_SHA256 bits=256/256); Fri, 23 Jun 2023 20:14:00 -0700 (PDT) From: Alexei Starovoitov To: daniel@iogearbox.net, andrii@kernel.org, void@manifault.com, houtao@huaweicloud.com, paulmck@kernel.org Cc: tj@kernel.org, rcu@vger.kernel.org, netdev@vger.kernel.org, bpf@vger.kernel.org, kernel-team@fb.com Subject: [PATCH v2 bpf-next 06/13] bpf: Optimize moving objects from free_by_rcu_ttrace to waiting_for_gp_ttrace. Date: Fri, 23 Jun 2023 20:13:26 -0700 Message-Id: <20230624031333.96597-7-alexei.starovoitov@gmail.com> X-Mailer: git-send-email 2.39.2 (Apple Git-143) In-Reply-To: <20230624031333.96597-1-alexei.starovoitov@gmail.com> References: <20230624031333.96597-1-alexei.starovoitov@gmail.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: rcu@vger.kernel.org From: Alexei Starovoitov Optimize moving objects from free_by_rcu_ttrace to waiting_for_gp_ttrace by remembering the tail. Signed-off-by: Alexei Starovoitov --- kernel/bpf/memalloc.c | 12 ++++++++---- 1 file changed, 8 insertions(+), 4 deletions(-) diff --git a/kernel/bpf/memalloc.c b/kernel/bpf/memalloc.c index b07368d77343..4fd79bd51f5a 100644 --- a/kernel/bpf/memalloc.c +++ b/kernel/bpf/memalloc.c @@ -101,6 +101,7 @@ struct bpf_mem_cache { /* list of objects to be freed after RCU tasks trace GP */ struct llist_head free_by_rcu_ttrace; + struct llist_node *free_by_rcu_ttrace_tail; struct llist_head waiting_for_gp_ttrace; struct rcu_head rcu_ttrace; atomic_t call_rcu_ttrace_in_progress; @@ -273,24 +274,27 @@ static void enque_to_free(struct bpf_mem_cache *c, void *obj) /* bpf_mem_cache is a per-cpu object. Freeing happens in irq_work. * Nothing races to add to free_by_rcu_ttrace list. */ - __llist_add(llnode, &c->free_by_rcu_ttrace); + if (__llist_add(llnode, &c->free_by_rcu_ttrace)) + c->free_by_rcu_ttrace_tail = llnode; } static void do_call_rcu_ttrace(struct bpf_mem_cache *c) { - struct llist_node *llnode, *t; + struct llist_node *llnode; if (atomic_xchg(&c->call_rcu_ttrace_in_progress, 1)) return; WARN_ON_ONCE(!llist_empty(&c->waiting_for_gp_ttrace)); - llist_for_each_safe(llnode, t, __llist_del_all(&c->free_by_rcu_ttrace)) + llnode = __llist_del_all(&c->free_by_rcu_ttrace); + if (llnode) /* There is no concurrent __llist_add(waiting_for_gp_ttrace) access. * It doesn't race with llist_del_all either. * But there could be two concurrent llist_del_all(waiting_for_gp_ttrace): * from __free_rcu() and from drain_mem_cache(). */ - __llist_add(llnode, &c->waiting_for_gp_ttrace); + __llist_add_batch(llnode, c->free_by_rcu_ttrace_tail, + &c->waiting_for_gp_ttrace); /* Use call_rcu_tasks_trace() to wait for sleepable progs to finish. * If RCU Tasks Trace grace period implies RCU grace period, free * these elements directly, else use call_rcu() to wait for normal