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
WARNING: multiple messages have this Message-ID (diff)
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 -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: <a href=mailto:"dont@kvack.org"> email@kvack.org </a>
next prev parent reply other threads:[~2017-01-18 13:18 UTC|newest] Thread overview: 124+ 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 ` Byungchul Park 2017-01-18 13:17 ` [PATCH v5 01/13] lockdep: Refactor lookup_chain_cache() Byungchul Park 2017-01-18 13:17 ` Byungchul Park 2017-01-19 9:16 ` Boqun Feng 2017-01-19 9:52 ` Byungchul Park 2017-01-19 9:52 ` Byungchul Park 2017-01-26 7:53 ` 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 ` 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 ` Byungchul Park 2017-01-18 13:17 ` [PATCH v5 04/13] lockdep: Refactor save_trace() Byungchul Park 2017-01-18 13:17 ` Byungchul Park 2017-01-18 13:17 ` Byungchul Park [this message] 2017-01-18 13:17 ` [PATCH v5 05/13] lockdep: Pass a callback arg to check_prev_add() to handle stack_trace Byungchul Park 2017-01-26 7:43 ` Byungchul Park 2017-01-26 7:43 ` Byungchul Park 2017-01-18 13:17 ` [PATCH v5 06/13] lockdep: Implement crossrelease feature Byungchul Park 2017-01-18 13:17 ` Byungchul Park 2017-02-28 12:26 ` Peter Zijlstra 2017-02-28 12:26 ` Peter Zijlstra 2017-02-28 12:45 ` Peter Zijlstra 2017-02-28 12:45 ` Peter Zijlstra 2017-02-28 12:49 ` Peter Zijlstra 2017-02-28 12:49 ` Peter Zijlstra 2017-03-01 6:20 ` Byungchul Park 2017-03-01 6:20 ` Byungchul Park 2017-02-28 13:05 ` Peter Zijlstra 2017-02-28 13:05 ` Peter Zijlstra 2017-02-28 13:28 ` Byungchul Park 2017-02-28 13:28 ` Byungchul Park 2017-02-28 13:35 ` Peter Zijlstra 2017-02-28 13:35 ` Peter Zijlstra 2017-02-28 14:00 ` Byungchul Park 2017-02-28 14:00 ` Byungchul Park 2017-02-28 13:10 ` Peter Zijlstra 2017-02-28 13:10 ` Peter Zijlstra 2017-02-28 13:24 ` Byungchul Park 2017-02-28 13:24 ` Byungchul Park 2017-02-28 18:29 ` Peter Zijlstra 2017-02-28 18:29 ` Peter Zijlstra 2017-03-01 4:40 ` Byungchul Park 2017-03-01 4:40 ` Byungchul Park 2017-03-01 10:45 ` Peter Zijlstra 2017-03-01 10:45 ` Peter Zijlstra 2017-03-01 12:10 ` Byungchul Park 2017-03-01 12:10 ` Byungchul Park 2017-02-28 13:40 ` Peter Zijlstra 2017-02-28 13:40 ` Peter Zijlstra 2017-03-01 5:43 ` Byungchul Park 2017-03-01 5:43 ` Byungchul Park 2017-03-01 12:28 ` Peter Zijlstra 2017-03-01 12:28 ` Peter Zijlstra 2017-03-02 13:40 ` Peter Zijlstra 2017-03-02 13:40 ` Peter Zijlstra 2017-03-03 0:17 ` Byungchul Park 2017-03-03 0:17 ` Byungchul Park 2017-03-03 8:14 ` Peter Zijlstra 2017-03-03 8:14 ` Peter Zijlstra 2017-03-03 9:13 ` Peter Zijlstra 2017-03-03 9:13 ` Peter Zijlstra 2017-03-03 9:32 ` Peter Zijlstra 2017-03-03 9:32 ` Peter Zijlstra 2017-03-05 3:33 ` Byungchul Park 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 2017-03-05 3:08 ` Byungchul Park 2017-03-07 11:42 ` Peter Zijlstra 2017-03-07 11:42 ` Peter Zijlstra 2017-03-03 0:39 ` Byungchul Park 2017-03-03 0:39 ` Byungchul Park 2017-02-28 15:49 ` Peter Zijlstra 2017-02-28 15:49 ` Peter Zijlstra 2017-03-01 5:17 ` Byungchul Park 2017-03-01 5:17 ` Byungchul Park 2017-03-01 6:18 ` Byungchul Park 2017-03-01 6:18 ` Byungchul Park 2017-03-02 2:52 ` Byungchul Park 2017-03-02 2:52 ` Byungchul Park 2017-02-28 18:15 ` Peter Zijlstra 2017-02-28 18:15 ` Peter Zijlstra 2017-03-01 7:21 ` Byungchul Park 2017-03-01 7:21 ` Byungchul Park 2017-03-01 10:43 ` Peter Zijlstra 2017-03-01 10:43 ` Peter Zijlstra 2017-03-01 12:27 ` Byungchul Park 2017-03-01 12:27 ` Byungchul Park 2017-03-02 4:20 ` Matthew Wilcox 2017-03-02 4:20 ` Matthew Wilcox 2017-03-02 4:45 ` byungchul.park 2017-03-02 4:45 ` byungchul.park 2017-03-02 14:39 ` Matthew Wilcox 2017-03-02 14:39 ` Matthew Wilcox 2017-03-02 23:50 ` Byungchul Park 2017-03-02 23:50 ` Byungchul Park 2017-03-05 8:01 ` Byungchul Park 2017-03-05 8:01 ` Byungchul Park 2017-03-14 7:36 ` Byungchul Park 2017-03-14 7:36 ` Byungchul Park 2017-03-02 13:41 ` Peter Zijlstra 2017-03-02 13:41 ` Peter Zijlstra 2017-03-02 23:43 ` Byungchul Park 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 ` Byungchul Park 2017-01-18 13:17 ` [PATCH v5 08/13] lockdep: Apply crossrelease to completions Byungchul Park 2017-01-18 13:17 ` Byungchul Park 2017-01-18 13:17 ` [PATCH v5 09/13] pagemap.h: Remove trailing white space Byungchul Park 2017-01-18 13:17 ` 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 ` 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 ` 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 ` Byungchul Park 2017-01-18 13:17 ` [PATCH v5 13/13] lockdep: Crossrelease feature documentation Byungchul Park 2017-01-18 13:17 ` Byungchul Park 2017-01-20 9:08 ` [REVISED DOCUMENT] " Byungchul Park 2017-01-20 9:08 ` Byungchul Park 2017-02-20 8:38 ` [PATCH v5 00/13] lockdep: Implement crossrelease feature Byungchul Park 2017-02-20 8:38 ` Byungchul Park
Reply instructions: You may reply publicly to this message via plain-text email using any one of the following methods: * Save the following mbox file, import it into your mail client, and reply-to-all from there: mbox Avoid top-posting and favor interleaved quoting: https://en.wikipedia.org/wiki/Posting_style#Interleaved_style * Reply using the --to, --cc, and --in-reply-to switches of git-send-email(1): git send-email \ --in-reply-to=1484745459-2055-6-git-send-email-byungchul.park@lge.com \ --to=byungchul.park@lge.com \ --cc=akpm@linux-foundation.org \ --cc=boqun.feng@gmail.com \ --cc=iamjoonsoo.kim@lge.com \ --cc=kirill@shutemov.name \ --cc=linux-kernel@vger.kernel.org \ --cc=linux-mm@kvack.org \ --cc=mingo@kernel.org \ --cc=npiggin@gmail.com \ --cc=peterz@infradead.org \ --cc=tglx@linutronix.de \ --cc=walken@google.com \ /path/to/YOUR_REPLY https://kernel.org/pub/software/scm/git/docs/git-send-email.html * If your mail client supports setting the In-Reply-To header via mailto: links, try the mailto: linkBe sure your reply has a Subject: header at the top and a blank line before the message body.
This is an external index of several public inboxes, see mirroring instructions on how to clone and mirror all data and code used by this external index.