From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI, SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=unavailable autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 4A6D6C43331 for ; Mon, 30 Mar 2020 02:34:14 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 1F0CD20780 for ; Mon, 30 Mar 2020 02:34:14 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=joelfernandes.org header.i=@joelfernandes.org header.b="n8ZFtlSW" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729141AbgC3Cdo (ORCPT ); Sun, 29 Mar 2020 22:33:44 -0400 Received: from mail-qk1-f194.google.com ([209.85.222.194]:38636 "EHLO mail-qk1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729076AbgC3Cdk (ORCPT ); Sun, 29 Mar 2020 22:33:40 -0400 Received: by mail-qk1-f194.google.com with SMTP id h14so17551301qke.5 for ; Sun, 29 Mar 2020 19:33:38 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=joelfernandes.org; s=google; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=+SC1wb04vPFRHvA69idHFJ/D6TQHtUQk5KfrhqDEopc=; b=n8ZFtlSWpZkaejINrNFAgQe81mPm1qWw92alN9sRCcqMfUbbD+oO2me5NN9T23SnJB OGq7zOh2DqT7DRspsD/Mnk5C1Al6o2RjKHcfVq86GVhWCuMmRlVru+fvyVpWfYwn5FAV qQNh0nYHY0ZBoY2rruGIs8jCY5RCLAvmcz604= X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20161025; h=x-gm-message-state:from:to:cc:subject:date:message-id:in-reply-to :references:mime-version:content-transfer-encoding; bh=+SC1wb04vPFRHvA69idHFJ/D6TQHtUQk5KfrhqDEopc=; b=TbdVIRe3NGs8Yatg+kmPnMal0mBmeVkjU6a+pd/4cprCBVtACNNiwaFbt4g1wza2II m3AJ7azuIXIYw6+KFNcw9lok7bFpwicJdy3KfGicZSRlZqSVc+yitjYCDKRuMQh546hO L7jobjLM5nwjbYIQmEHQH6tBMhtQvwE6rf5yb9fXlSCP2208CODpZ6El0XII1MZdY4Nb jqC0SHuv5BoVZKvNiVfx7oeqQzaAVCmmVGUVUgr/Qfn2cyoUm5ywHasSD+VBI06q/wKH 9YO8KDPB0SNWCTanxVbkDR7X7P1jPj/cEVdmSyWeg7Tgbli+s5Q3ftvMbaHxrOwnXvJ9 4/0w== X-Gm-Message-State: ANhLgQ0p0Vl10JApNE+vuXO9yknKSgs7QNBsumBFyE/vduKoY6FAK4gQ 0AH2WqZRcoPCz5NbjYxctby+bNUZbeg= X-Google-Smtp-Source: ADFU+vszNuc31kIyM2RoqVUpLdVvAYIJ6JetNU3ZOQhTJ5Je0FGvESstvuE4ZqfTJltehBQY4GpxHg== X-Received: by 2002:a37:db0a:: with SMTP id e10mr9787278qki.273.1585535618038; Sun, 29 Mar 2020 19:33:38 -0700 (PDT) Received: from joelaf.cam.corp.google.com ([2620:15c:6:12:9c46:e0da:efbf:69cc]) by smtp.gmail.com with ESMTPSA id q15sm10030625qtj.83.2020.03.29.19.33.37 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Sun, 29 Mar 2020 19:33:37 -0700 (PDT) From: "Joel Fernandes (Google)" To: linux-kernel@vger.kernel.org Cc: "Joel Fernandes (Google)" , Andrew Morton , Ingo Molnar , Josh Triplett , Lai Jiangshan , linux-mm@kvack.org, Mathieu Desnoyers , "Paul E. McKenney" , "Rafael J. Wysocki" , rcu@vger.kernel.org, Steven Rostedt , "Uladzislau Rezki (Sony)" Subject: [PATCH 07/18] rcu/tree: Simplify debug_objects handling Date: Sun, 29 Mar 2020 22:32:37 -0400 Message-Id: <20200330023248.164994-8-joel@joelfernandes.org> X-Mailer: git-send-email 2.26.0.rc2.310.g2932bb562d-goog In-Reply-To: <20200330023248.164994-1-joel@joelfernandes.org> References: <20200330023248.164994-1-joel@joelfernandes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org In order to prepare for future changes for headless RCU support, make the debug_objects handling in kfree_rcu use the final 'pointer' value of the object, instead of depending on the head. Signed-off-by: Joel Fernandes (Google) --- kernel/rcu/tree.c | 30 +++++++++++++----------------- 1 file changed, 13 insertions(+), 17 deletions(-) diff --git a/kernel/rcu/tree.c b/kernel/rcu/tree.c index 3fb19ea039912..95d1f5e20d5ec 100644 --- a/kernel/rcu/tree.c +++ b/kernel/rcu/tree.c @@ -2825,7 +2825,6 @@ struct kfree_rcu_bulk_data { unsigned long nr_records; void *records[KFREE_BULK_MAX_ENTR]; struct kfree_rcu_bulk_data *next; - struct rcu_head *head_free_debug; }; /** @@ -2875,11 +2874,11 @@ struct kfree_rcu_cpu { static DEFINE_PER_CPU(struct kfree_rcu_cpu, krc); static __always_inline void -debug_rcu_head_unqueue_bulk(struct rcu_head *head) +debug_rcu_bhead_unqueue(struct kfree_rcu_bulk_data *bhead) { #ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD - for (; head; head = head->next) - debug_rcu_head_unqueue(head); + for (int i = 0; i < bhead->nr_records; i++) + debug_rcu_head_unqueue((struct rcu_head *)(bhead->records[i])); #endif } @@ -2909,7 +2908,7 @@ static void kfree_rcu_work(struct work_struct *work) for (; bhead; bhead = bnext) { bnext = bhead->next; - debug_rcu_head_unqueue_bulk(bhead->head_free_debug); + debug_rcu_bhead_unqueue(bhead); rcu_lock_acquire(&rcu_callback_map); trace_rcu_invoke_kfree_bulk_callback(rcu_state.name, @@ -2931,14 +2930,15 @@ static void kfree_rcu_work(struct work_struct *work) */ for (; head; head = next) { unsigned long offset = (unsigned long)head->func; + void *ptr = (void *)head - offset; next = head->next; - debug_rcu_head_unqueue(head); + debug_rcu_head_unqueue((struct rcu_head *)ptr); rcu_lock_acquire(&rcu_callback_map); trace_rcu_invoke_kvfree_callback(rcu_state.name, head, offset); if (!WARN_ON_ONCE(!__is_kvfree_rcu_offset(offset))) - kvfree((void *)head - offset); + kvfree(ptr); rcu_lock_release(&rcu_callback_map); cond_resched_tasks_rcu_qs(); @@ -3062,18 +3062,11 @@ kfree_call_rcu_add_ptr_to_bulk(struct kfree_rcu_cpu *krcp, /* Initialize the new block. */ bnode->nr_records = 0; bnode->next = krcp->bhead; - bnode->head_free_debug = NULL; /* Attach it to the head. */ krcp->bhead = bnode; } -#ifdef CONFIG_DEBUG_OBJECTS_RCU_HEAD - head->func = func; - head->next = krcp->bhead->head_free_debug; - krcp->bhead->head_free_debug = head; -#endif - /* Finally insert. */ krcp->bhead->records[krcp->bhead->nr_records++] = (void *) head - (unsigned long) func; @@ -3097,14 +3090,17 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) { unsigned long flags; struct kfree_rcu_cpu *krcp; + void *ptr; local_irq_save(flags); // For safely calling this_cpu_ptr(). krcp = this_cpu_ptr(&krc); if (krcp->initialized) spin_lock(&krcp->lock); + ptr = (void *)head - (unsigned long)func; + // Queue the object but don't yet schedule the batch. - if (debug_rcu_head_queue(head)) { + if (debug_rcu_head_queue(ptr)) { // Probable double kfree_rcu(), just leak. WARN_ONCE(1, "%s(): Double-freed call. rcu_head %p\n", __func__, head); @@ -3121,8 +3117,8 @@ void kvfree_call_rcu(struct rcu_head *head, rcu_callback_t func) * Under high memory pressure GFP_NOWAIT can fail, * in that case the emergency path is maintained. */ - if (is_vmalloc_addr((void *) head - (unsigned long) func) || - !kfree_call_rcu_add_ptr_to_bulk(krcp, head, func)) { + if (is_vmalloc_addr(ptr) || + !kfree_call_rcu_add_ptr_to_bulk(krcp, head, func)) { head->func = func; head->next = krcp->head; krcp->head = head; -- 2.26.0.rc2.310.g2932bb562d-goog