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,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, 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 C1C1FC04AB1 for ; Mon, 13 May 2019 09:13:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 8F0A820989 for ; Mon, 13 May 2019 09:13:26 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (2048-bit key) header.d=gmail.com header.i=@gmail.com header.b="jhwRlW68" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728615AbfEMJN0 (ORCPT ); Mon, 13 May 2019 05:13:26 -0400 Received: from mail-pg1-f194.google.com ([209.85.215.194]:39314 "EHLO mail-pg1-f194.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727576AbfEMJNY (ORCPT ); Mon, 13 May 2019 05:13:24 -0400 Received: by mail-pg1-f194.google.com with SMTP id w22so6450939pgi.6 for ; Mon, 13 May 2019 02:13:24 -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=QxtXj8UtQSYghHEfN3xnKKzkOFQGRnYE90nTsl6Ujjg=; b=jhwRlW68xzcAAcGuoqMH5yNgAbFIu6vd+KomvwtilVIysTWq2oVqDTQApiqUDxI9pC VtOzK33YPNcHJVvNppomR9Brki+JSDqX7qzUuE8FYDsj+RKA33Qj+gdN/ZE8v/PHNkkG p5DJDYW+0iy1cQAqY/y/V8RoJCeSUbSWqnVD7od2Lj36cub8AXJYyzHcbMJctfltle8G UhKDwnYHCVk/fUvDC5SfIV/c+1+KHGjXeveGzjmZze+qYkpCx/4zVFiH0iwsMcpX+iwK 2m9ehhovfHDmmbvPEhHKAk7WBS/daG1Ffg3OXPnGfgkan0sub5qQy3N2BZ/iIKBL0kMb Ng+A== 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=QxtXj8UtQSYghHEfN3xnKKzkOFQGRnYE90nTsl6Ujjg=; b=KuMhI+rHmFGXdp0S/rx4BQBHlAuXy5dpjc6u7Z/+9IHJUNJ1mM5mvvThG46afubB21 6mNZa9uwtOP1v8Ar+KHT9Xn+sUgY9FpDnY43Q9XSll4/lAP7bKIh8RIwk/MDLLsB3AnE HFpTwwDLf7qMOMKKut7qLpryoF7OB+Al2H081ycf1obyaZKpfkHhtg6PuUXYfd3ouK58 sj9tMxXVSUTT/p920RBjEPFUwOqA7RQgln9EtZOuA8CWQ6d9K9KyLIXshqoFeW4+hilD IMMMpJKkqV0uApgjy2WSwGrYxwk3EjslbiXU8RYjiUuXW8A6QlOFRkodD0UItXwqyk/8 gh2w== X-Gm-Message-State: APjAAAUdOP2ZhDso3Ixy2ExQvjSvpcCGA5kW4HWUy8ZuNYG/+nf/7hfO 5o+YNKOfIf/TkSoIo/n9BJA= X-Google-Smtp-Source: APXvYqzS6CutaQhgmW9u/OlX3akEfqIezW5lXM2ozxu6RsxsH/sBA8HGWMo6pKQouLVAJXn99Z6Kmg== X-Received: by 2002:a65:63d5:: with SMTP id n21mr29675339pgv.330.1557738803899; Mon, 13 May 2019 02:13:23 -0700 (PDT) Received: from localhost.localdomain ([203.100.54.194]) by smtp.gmail.com with ESMTPSA id n18sm35500837pfi.48.2019.05.13.02.13.20 (version=TLS1_2 cipher=ECDHE-RSA-AES128-GCM-SHA256 bits=128/128); Mon, 13 May 2019 02:13:23 -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, linux-kernel@vger.kernel.org, Yuyang Du Subject: [PATCH 02/17] locking/lockdep: Add read-write type for dependency Date: Mon, 13 May 2019 17:11:48 +0800 Message-Id: <20190513091203.7299-3-duyuyang@gmail.com> X-Mailer: git-send-email 2.20.1 (Apple Git-117) In-Reply-To: <20190513091203.7299-1-duyuyang@gmail.com> References: <20190513091203.7299-1-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 helpers 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 441288c..6aa9af2 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 e9eafcf..4091002 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