From: Byungchul Park <byungchul.park@lge.com>
To: peterz@infradead.org, mingo@kernel.org
Cc: tglx@linutronix.de, walken@google.com, boqun.feng@gmail.com,
kirill@shutemov.name, linux-kernel@vger.kernel.org,
linux-mm@kvack.org, iamjoonsoo.kim@lge.com,
akpm@linux-foundation.org, npiggin@gmail.com
Subject: [PATCH v5 05/13] lockdep: Pass a callback arg to check_prev_add() to handle stack_trace
Date: Wed, 18 Jan 2017 22:17:31 +0900 [thread overview]
Message-ID: <1484745459-2055-6-git-send-email-byungchul.park@lge.com> (raw)
In-Reply-To: <1484745459-2055-1-git-send-email-byungchul.park@lge.com>
Currently, a separate stack_trace instance cannot be used in
check_prev_add(). The simplest way to achieve it is to pass a
stack_trace instance to check_prev_add() as an argument after
saving it. However, unnecessary saving can happen if so implemented.
The proper solution is to pass a callback function additionally along
with a stack_trace so that a caller can decide the way to save, for
example, doing nothing, calling save_trace() or doing something else.
Actually, crossrelease don't need to save stack_trace of current but
only need to copy stack_traces from temporary buffers to the global
stack_trace[].
Signed-off-by: Byungchul Park <byungchul.park@lge.com>
---
kernel/locking/lockdep.c | 38 ++++++++++++++++++--------------------
1 file changed, 18 insertions(+), 20 deletions(-)
diff --git a/kernel/locking/lockdep.c b/kernel/locking/lockdep.c
index e63ff97..75dc14a 100644
--- a/kernel/locking/lockdep.c
+++ b/kernel/locking/lockdep.c
@@ -1805,20 +1805,13 @@ static inline void inc_chains(void)
*/
static int
check_prev_add(struct task_struct *curr, struct held_lock *prev,
- struct held_lock *next, int distance, int *stack_saved)
+ struct held_lock *next, int distance, struct stack_trace *trace,
+ int (*save)(struct stack_trace *trace))
{
struct lock_list *entry;
int ret;
struct lock_list this;
struct lock_list *uninitialized_var(target_entry);
- /*
- * Static variable, serialized by the graph_lock().
- *
- * We use this static variable to save the stack trace in case
- * we call into this function multiple times due to encountering
- * trylocks in the held lock stack.
- */
- static struct stack_trace trace;
/*
* Prove that the new <prev> -> <next> dependency would not
@@ -1866,11 +1859,8 @@ static inline void inc_chains(void)
}
}
- if (!*stack_saved) {
- if (!save_trace(&trace))
- return 0;
- *stack_saved = 1;
- }
+ if (save && !save(trace))
+ return 0;
/*
* Ok, all validations passed, add the new lock
@@ -1878,14 +1868,14 @@ static inline void inc_chains(void)
*/
ret = add_lock_to_list(hlock_class(prev), hlock_class(next),
&hlock_class(prev)->locks_after,
- next->acquire_ip, distance, &trace);
+ next->acquire_ip, distance, trace);
if (!ret)
return 0;
ret = add_lock_to_list(hlock_class(next), hlock_class(prev),
&hlock_class(next)->locks_before,
- next->acquire_ip, distance, &trace);
+ next->acquire_ip, distance, trace);
if (!ret)
return 0;
@@ -1893,8 +1883,6 @@ static inline void inc_chains(void)
* Debugging printouts:
*/
if (verbose(hlock_class(prev)) || verbose(hlock_class(next))) {
- /* We drop graph lock, so another thread can overwrite trace. */
- *stack_saved = 0;
graph_unlock();
printk("\n new dependency: ");
print_lock_name(hlock_class(prev));
@@ -1917,8 +1905,10 @@ static inline void inc_chains(void)
check_prevs_add(struct task_struct *curr, struct held_lock *next)
{
int depth = curr->lockdep_depth;
- int stack_saved = 0;
struct held_lock *hlock;
+ struct stack_trace trace;
+ unsigned long start_nr = nr_stack_trace_entries;
+ int (*save)(struct stack_trace *trace) = save_trace;
/*
* Debugging checks.
@@ -1944,8 +1934,16 @@ static inline void inc_chains(void)
*/
if (hlock->read != 2 && hlock->check) {
if (!check_prev_add(curr, hlock, next,
- distance, &stack_saved))
+ distance, &trace, save))
return 0;
+
+ /*
+ * Stop saving stack_trace if save_trace() was
+ * called at least once:
+ */
+ if (save && start_nr != nr_stack_trace_entries)
+ save = NULL;
+
/*
* Stop after the first non-trylock entry,
* as non-trylock entries have added their
--
1.9.1
next prev parent reply other threads:[~2017-01-18 13:18 UTC|newest]
Thread overview: 63+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-01-18 13:17 [PATCH v5 00/13] lockdep: Implement crossrelease feature Byungchul Park
2017-01-18 13:17 ` [PATCH v5 01/13] lockdep: Refactor lookup_chain_cache() Byungchul Park
2017-01-19 9:16 ` Boqun Feng
2017-01-19 9:52 ` Byungchul Park
2017-01-26 7:53 ` Byungchul Park
2017-01-18 13:17 ` [PATCH v5 02/13] lockdep: Fix wrong condition to print bug msgs for MAX_LOCKDEP_CHAIN_HLOCKS Byungchul Park
2017-01-18 13:17 ` [PATCH v5 03/13] lockdep: Add a function building a chain between two classes Byungchul Park
2017-01-18 13:17 ` [PATCH v5 04/13] lockdep: Refactor save_trace() Byungchul Park
2017-01-18 13:17 ` Byungchul Park [this message]
2017-01-26 7:43 ` [PATCH v5 05/13] lockdep: Pass a callback arg to check_prev_add() to handle stack_trace Byungchul Park
2017-01-18 13:17 ` [PATCH v5 06/13] lockdep: Implement crossrelease feature Byungchul Park
2017-02-28 12:26 ` Peter Zijlstra
2017-02-28 12:45 ` Peter Zijlstra
2017-02-28 12:49 ` Peter Zijlstra
2017-03-01 6:20 ` Byungchul Park
2017-02-28 13:05 ` Peter Zijlstra
2017-02-28 13:28 ` Byungchul Park
2017-02-28 13:35 ` Peter Zijlstra
2017-02-28 14:00 ` Byungchul Park
2017-02-28 13:10 ` Peter Zijlstra
2017-02-28 13:24 ` Byungchul Park
2017-02-28 18:29 ` Peter Zijlstra
2017-03-01 4:40 ` Byungchul Park
2017-03-01 10:45 ` Peter Zijlstra
2017-03-01 12:10 ` Byungchul Park
2017-02-28 13:40 ` Peter Zijlstra
2017-03-01 5:43 ` Byungchul Park
2017-03-01 12:28 ` Peter Zijlstra
2017-03-02 13:40 ` Peter Zijlstra
2017-03-03 0:17 ` Byungchul Park
2017-03-03 8:14 ` Peter Zijlstra
2017-03-03 9:13 ` Peter Zijlstra
2017-03-03 9:32 ` Peter Zijlstra
2017-03-05 3:33 ` Byungchul Park
2017-08-10 12:18 ` [tip:locking/core] locking/lockdep: Avoid creating redundant links tip-bot for Peter Zijlstra
2017-03-05 3:08 ` [PATCH v5 06/13] lockdep: Implement crossrelease feature Byungchul Park
2017-03-07 11:42 ` Peter Zijlstra
2017-03-03 0:39 ` Byungchul Park
2017-02-28 15:49 ` Peter Zijlstra
2017-03-01 5:17 ` Byungchul Park
2017-03-01 6:18 ` Byungchul Park
2017-03-02 2:52 ` Byungchul Park
2017-02-28 18:15 ` Peter Zijlstra
2017-03-01 7:21 ` Byungchul Park
2017-03-01 10:43 ` Peter Zijlstra
2017-03-01 12:27 ` Byungchul Park
2017-03-02 4:20 ` Matthew Wilcox
2017-03-02 4:45 ` byungchul.park
2017-03-02 14:39 ` Matthew Wilcox
2017-03-02 23:50 ` Byungchul Park
2017-03-05 8:01 ` Byungchul Park
2017-03-14 7:36 ` Byungchul Park
2017-03-02 13:41 ` Peter Zijlstra
2017-03-02 23:43 ` Byungchul Park
2017-01-18 13:17 ` [PATCH v5 07/13] lockdep: Make print_circular_bug() aware of crossrelease Byungchul Park
2017-01-18 13:17 ` [PATCH v5 08/13] lockdep: Apply crossrelease to completions Byungchul Park
2017-01-18 13:17 ` [PATCH v5 09/13] pagemap.h: Remove trailing white space Byungchul Park
2017-01-18 13:17 ` [PATCH v5 10/13] lockdep: Apply crossrelease to PG_locked locks Byungchul Park
2017-01-18 13:17 ` [PATCH v5 11/13] lockdep: Apply lock_acquire(release) on __Set(__Clear)PageLocked Byungchul Park
2017-01-18 13:17 ` [PATCH v5 12/13] lockdep: Move data of CONFIG_LOCKDEP_PAGELOCK from page to page_ext Byungchul Park
2017-01-18 13:17 ` [PATCH v5 13/13] lockdep: Crossrelease feature documentation Byungchul Park
2017-01-20 9:08 ` [REVISED DOCUMENT] " Byungchul Park
2017-02-20 8:38 ` [PATCH v5 00/13] lockdep: Implement crossrelease feature Byungchul Park
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