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=-9.1 required=3.0 tests=DKIM_SIGNED,DKIM_VALID, DKIM_VALID_AU,FREEMAIL_FORGED_FROMDOMAIN,FREEMAIL_FROM, HEADER_FROM_DIFFERENT_DOMAINS,HK_RANDOM_FROM,INCLUDES_PATCH, MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 09A87C04AB4 for ; Thu, 16 May 2019 08:00:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C63C220881 for ; Thu, 16 May 2019 08:00:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="r0XtiUFa" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726812AbfEPIAd (ORCPT ); Thu, 16 May 2019 04:00:33 -0400 Received: from mail-pl1-f195.google.com ([209.85.214.195]:37045 "EHLO mail-pl1-f195.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726363AbfEPIAb (ORCPT ); Thu, 16 May 2019 04:00:31 -0400 Received: by mail-pl1-f195.google.com with SMTP id p15so1223497pll.4 for ; Thu, 16 May 2019 01:00:31 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=gmail.com; s=20161025; h=from:to:cc:subject:date:message-id:in-reply-to:references :mime-version:content-transfer-encoding; bh=jIveG1D7r7idiQG14j1Qu/8FicgeCmdaO791tOVIC/o=; b=r0XtiUFap0XXt2eMGFhzNjgzKrjxz+MK4MKYgXMK1xW1CkNzzVXBHXlQf4NZP3j3sg 0aRa7msT0O27es+4KSZBiglhDAdId2//zLJPUS5IZl8ElatDgo1ttfTNXYFbNry2Pjy9 EA0dfTzdG8CjN6HhHOpyYU1sDHe5cyGsVQS1V6mtgrTaE1GpGVi0LY0HcATcG8zRPKDt Zg6QgB/AnEaTFToCJiDyYS/DjuBYlo3iUyfL0Ua1ZeguvLLn0+uWveE5AL+y49CN9HlG yXV2rIS/MnBXKnZZ/OCgQpXyv7T+lvU+UXQl1Vt7G9TIMjzn33L6kjnBMJNpAzCpgBm1 0DuQ== 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=jIveG1D7r7idiQG14j1Qu/8FicgeCmdaO791tOVIC/o=; b=AI45owlw8NIbPUo/9s54tBbVTkNi/9KDW+yOzJKMcPZplidZCSkTtxWPybW+3hiiV/ 0cJrhoCW4YYorGR3opCLJ7i/vgFnxoKb9iBlFsOk9/iMNmhT/vlYuXEWxSS3P50vZ0U7 KZMwIZ/xcn2WcRbJHUkNTmG5W8NKJsZCGWiKFWP89EYPVJmCRtt4enNTbav9tqU2nwIj u/eEw1gTCEes3O2yEMVLLldXlyYqu3Aq+6Sdwf8N+9TiwGvCByi53XcCPmEdzYO9t1KG TD0dh++8p5Qcxsn8gdY0ODygML2NahO/ZnIzDlJCVgcajA1GmnSMeSsso/Auj5olPr/6 3z7A== X-Gm-Message-State: APjAAAVsDLMpkeTqjQXCKa2PHos+6FK7KUSLMiD5P5yLVuDYNdWRIQDv KJN5vC2h5Lj/JxpYkSHRBhs= X-Google-Smtp-Source: APXvYqyfkuSWaKjiQletyzlB80FHEwLiftkuKnjfHle75K2K+PNcOFEOfT9Ovl7O8UwSvYhzJSgagg== X-Received: by 2002:a17:902:bd94:: with SMTP id q20mr26110168pls.146.1557993630692; Thu, 16 May 2019 01:00:30 -0700 (PDT) Received: from localhost.localdomain ([203.100.54.194]) by smtp.gmail.com with ESMTPSA id p7sm2051471pgb.92.2019.05.16.01.00.27 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Thu, 16 May 2019 01:00:30 -0700 (PDT) From: Yuyang Du To: peterz@infradead.org, will.deacon@arm.com, mingo@kernel.org Cc: bvanassche@acm.org, ming.lei@redhat.com, frederic@kernel.org, tglx@linutronix.de, boqun.feng@gmail.com, paulmck@linux.ibm.com, linux-kernel@vger.kernel.org, Yuyang Du Subject: [PATCH v2 02/17] locking/lockdep: Add read-write type for dependency Date: Thu, 16 May 2019 16:00:00 +0800 Message-Id: <20190516080015.16033-3-duyuyang@gmail.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) In-Reply-To: <20190516080015.16033-1-duyuyang@gmail.com> References: <20190516080015.16033-1-duyuyang@gmail.com> 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 Direct dependency needs to keep track of its locks' read-write types. A union field is added to lock_list struct so the type is stored there as this: lock_type[1] (u16), lock_type[0] (u16) or: dep_type (int) where value: 0: exclusive / write 1: read 2: recursive read Note that (int) dep_type value may vary with different architectural endianness, so use helper functions to operate on these types. Signed-off-by: Yuyang Du --- include/linux/lockdep.h | 12 ++++++++++++ kernel/locking/lockdep.c | 34 +++++++++++++++++++++++++++++++--- kernel/locking/lockdep_internals.h | 3 +++ 3 files changed, 46 insertions(+), 3 deletions(-) diff --git a/include/linux/lockdep.h b/include/linux/lockdep.h index 1009c47..bc09c85 100644 --- a/include/linux/lockdep.h +++ b/include/linux/lockdep.h @@ -195,6 +195,18 @@ struct lock_list { struct lock_class *links_to; struct lock_trace trace; int distance; + /* + * This field keeps track of the read-write type of this dependency. + * + * With L1 -> L2: + * + * lock_type[0] stores the type of L1, while lock_type[1] stores the + * type of L2. + */ + union { + int dep_type; + u16 lock_type[2]; + }; /* * The parent field is used to implement breadth-first search, and the diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c index fb6be63..e7eedbf 100644 --- a/kernel/locking/lockdep.c +++ b/kernel/locking/lockdep.c @@ -1225,7 +1225,7 @@ static struct lock_list *alloc_list_entry(void) static int add_lock_to_list(struct lock_class *this, struct lock_class *links_to, struct list_head *head, unsigned long ip, int distance, - struct lock_trace *trace) + struct lock_trace *trace, int dep_type) { struct lock_list *entry; /* @@ -1240,6 +1240,8 @@ static int add_lock_to_list(struct lock_class *this, entry->links_to = links_to; entry->distance = distance; entry->trace = *trace; + entry->dep_type = dep_type; + /* * Both allocation and removal are done under the graph lock; but * iteration is under RCU-sched; see look_up_lock_class() and @@ -1677,6 +1679,30 @@ unsigned long lockdep_count_backward_deps(struct lock_class *class) return ret; } +static inline int get_dep_type(struct held_lock *lock1, struct held_lock *lock2) +{ + /* + * With dependency lock1 -> lock2: + * + * lock_type[0] is lock1, while lock_type[1] is lock2. + * + * Avoid architectural endianness difference composing dep_type. + */ + u16 type[2] = { lock1->read, lock2->read }; + + return *(int *)type; +} + +static inline int get_lock_type1(struct lock_list *lock) +{ + return lock->lock_type[0]; +} + +static inline int get_lock_type2(struct lock_list *lock) +{ + return lock->lock_type[1]; +} + /* * Check that the dependency graph starting at can lead to * or not. Print an error and return 0 if it does. @@ -2446,14 +2472,16 @@ static inline void inc_chains(void) */ ret = add_lock_to_list(hlock_class(next), hlock_class(prev), &hlock_class(prev)->locks_after, - next->acquire_ip, distance, trace); + next->acquire_ip, distance, trace, + get_dep_type(prev, next)); if (!ret) return 0; ret = add_lock_to_list(hlock_class(prev), hlock_class(next), &hlock_class(next)->locks_before, - next->acquire_ip, distance, trace); + next->acquire_ip, distance, trace, + get_dep_type(next, prev)); if (!ret) return 0; diff --git a/kernel/locking/lockdep_internals.h b/kernel/locking/lockdep_internals.h index 150ec3f..c287bcb 100644 --- a/kernel/locking/lockdep_internals.h +++ b/kernel/locking/lockdep_internals.h @@ -26,6 +26,9 @@ enum lock_usage_bit { #define LOCK_USAGE_DIR_MASK 2 #define LOCK_USAGE_STATE_MASK (~(LOCK_USAGE_READ_MASK | LOCK_USAGE_DIR_MASK)) +#define LOCK_TYPE_BITS 16 +#define LOCK_TYPE_MASK 0xFFFF + /* * Usage-state bitmasks: */ -- 1.8.3.1