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From: Boqun Feng <boqun.feng@gmail.com>
To: linux-kernel@vger.kernel.org
Cc: Peter Zijlstra <peterz@infradead.org>,
	Ingo Molnar <mingo@redhat.com>,
	Andrea Parri <parri.andrea@gmail.com>,
	Boqun Feng <boqun.feng@gmail.com>
Subject: [RFC tip/locking/lockdep v5 09/17] lockdep: Add recursive read locks into dependency graph
Date: Thu, 22 Feb 2018 15:08:56 +0800	[thread overview]
Message-ID: <20180222070904.548-10-boqun.feng@gmail.com> (raw)
In-Reply-To: <20180222070904.548-1-boqun.feng@gmail.com>

Since we have all the fundamental to handle recursive read locks, we now
add them into the dependency graph.

Signed-off-by: Boqun Feng <boqun.feng@gmail.com>
---
 kernel/locking/lockdep.c | 16 +---------------
 1 file changed, 1 insertion(+), 15 deletions(-)

diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index bd3eef664f9d..254f90bade54 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -2038,16 +2038,6 @@ check_prev_add(struct task_struct *curr, struct held_lock *prev,
 	if (!check_prev_add_irq(curr, prev, next))
 		return 0;
 
-	/*
-	 * For recursive read-locks we do all the dependency checks,
-	 * but we dont store read-triggered dependencies (only
-	 * write-triggered dependencies). This ensures that only the
-	 * write-side dependencies matter, and that if for example a
-	 * write-lock never takes any other locks, then the reads are
-	 * equivalent to a NOP.
-	 */
-	if (next->read == 2 || prev->read == 2)
-		return 1;
 	/*
 	 * Is the <prev> -> <next> dependency already present?
 	 *
@@ -2151,11 +2141,7 @@ check_prevs_add(struct task_struct *curr, struct held_lock *next)
 		int distance = curr->lockdep_depth - depth + 1;
 		hlock = curr->held_locks + depth - 1;
 
-		/*
-		 * Only non-recursive-read entries get new dependencies
-		 * added:
-		 */
-		if (hlock->read != 2 && hlock->check) {
+		if (hlock->check) {
 			int ret = check_prev_add(curr, hlock, next, distance, &trace, save_trace);
 			if (!ret)
 				return 0;
-- 
2.16.1

  parent reply	other threads:[~2018-02-22  7:06 UTC|newest]

Thread overview: 53+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2018-02-22  7:08 [RFC tip/locking/lockdep v5 00/17] lockdep: Support deadlock detection for recursive read locks Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 01/17] lockdep: Demagic the return value of BFS Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 02/17] lockdep: Make __bfs() visit every dependency until a match Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 03/17] lockdep: Redefine LOCK_*_STATE* bits Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 04/17] lockdep: Introduce lock_list::dep Boqun Feng
2018-02-23 11:55   ` Peter Zijlstra
2018-02-23 12:37     ` Boqun Feng
2018-02-24  5:32       ` Boqun Feng
2018-02-24  6:30         ` Boqun Feng
2018-02-24  8:38           ` Peter Zijlstra
2018-02-24  9:00             ` Boqun Feng
2018-02-24  9:26               ` Boqun Feng
2018-02-26  9:00                 ` Peter Zijlstra
2018-02-26 10:15                   ` Boqun Feng
2018-02-26 10:20                     ` Boqun Feng
2018-02-24  7:31         ` Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 05/17] lockdep: Extend __bfs() to work with multiple kinds of dependencies Boqun Feng
2018-02-22 14:26   ` Peter Zijlstra
2018-02-22 15:12     ` Boqun Feng
2018-02-22 15:30       ` Peter Zijlstra
2018-02-22 15:51         ` Peter Zijlstra
2018-02-22 16:31           ` Boqun Feng
2018-02-23  5:02             ` Boqun Feng
2018-02-23 11:15               ` Peter Zijlstra
2018-02-22 16:08       ` Peter Zijlstra
2018-02-22 16:34         ` Boqun Feng
2018-02-22 16:32           ` Peter Zijlstra
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 06/17] lockdep: Support deadlock detection for recursive read in check_noncircular() Boqun Feng
2018-02-22 14:54   ` Peter Zijlstra
2018-02-22 15:16     ` Peter Zijlstra
2018-02-22 15:44       ` Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 07/17] lockdep: Adjust check_redundant() for recursive read change Boqun Feng
2018-02-22 17:29   ` Peter Zijlstra
2018-03-16  8:20     ` Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 08/17] lockdep: Fix recursive read lock related safe->unsafe detection Boqun Feng
2018-02-22 17:41   ` Peter Zijlstra
2018-02-22 17:46   ` Peter Zijlstra
2018-02-23  8:21     ` Boqun Feng
2018-02-23  8:58       ` Boqun Feng
2018-02-23 11:36         ` Peter Zijlstra
2018-02-22  7:08 ` Boqun Feng [this message]
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 10/17] lockdep/selftest: Add a R-L/L-W test case specific to chain cache behavior Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 11/17] lockdep: Take read/write status in consideration when generate chainkey Boqun Feng
2018-02-22  7:08 ` [RFC tip/locking/lockdep v5 12/17] lockdep/selftest: Unleash irq_read_recursion2 and add more Boqun Feng
2018-02-22  7:09 ` [RFC tip/locking/lockdep v5 13/17] lockdep/selftest: Add more recursive read related test cases Boqun Feng
2018-02-22  7:09 ` [RFC tip/locking/lockdep v5 14/17] Revert "locking/lockdep/selftests: Fix mixed read-write ABBA tests" Boqun Feng
2018-02-22  7:09 ` [RFC tip/locking/lockdep v5 15/17] lockdep: Reduce the size of lock_list Boqun Feng
2018-02-23 11:38   ` Peter Zijlstra
2018-02-23 12:40     ` Boqun Feng
2018-02-22  7:09 ` [RFC tip/locking/lockdep v5 16/17] lockdep: Documention for recursive read lock detection reasoning Boqun Feng
2018-02-24 22:53   ` Andrea Parri
2018-02-27  2:32     ` Boqun Feng
2018-02-22  7:09 ` [RFC tip/locking/lockdep v5 17/17] MAINTAINERS: Add myself as a LOCKING PRIMITIVES reviewer Boqun Feng

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