Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932353Ab0DVUQX (ORCPT ); Thu, 22 Apr 2010 16:16:23 -0400 Received: from mail-ew0-f220.google.com ([209.85.219.220]:34722 "EHLO mail-ew0-f220.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932065Ab0DVUQM (ORCPT ); Thu, 22 Apr 2010 16:16:12 -0400 DomainKey-Signature: a=rsa-sha1; c=nofws; d=gmail.com; s=gamma; h=date:from:x-x-sender:to:cc:subject:message-id:user-agent :mime-version:content-type; b=xtMm+iheOfQ2VP4/2Vh2llOZDTUYeBjaHhk56owxpODb6Ct7fhY1jQdD3roViKzsjt rZv5yiOhhBA2E9l9VeU/bb3g4PRjXmu1r7qKON6SJh49Jqeu78hOUrSHGseQc0t46zQu RklGgPhJ+pBdbUzA5e3DvXp36mkwi4frmyBDU= Date: Thu, 22 Apr 2010 22:15:48 +0200 (CEST) From: John Kacur X-X-Sender: jkacur@localhost To: Peter Zijlstra , LKML cc: linux-rt-users , Sven-Thorsten Dietrich , Clark Williams , "Luis Claudio R. Goncalves" , Ingo Molnar , Thomas Gleixner , Gregory Haskins Subject: [PATCH] lockdep: Add nr_save_trace_invocations counter Message-ID: User-Agent: Alpine 2.00 (LFD 1167 2008-08-23) MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 5438 Lines: 156 NOT FOR INCLUSION I created this patch as a result of Peter Zilstra's request to get more info from lockdep. This patch is not for inclusion, at least in its present form, because it adds some redunant info to /proc/lockdep_stats However, some of the fields are new, and it is worth examining, and / or applying if you are looking at the MAX_STACK_TRACE_ENTRIES too big problem. I generated this patch against a recent tip/master but it applies without conflicts to the latest rt kernel as well. Comments are welcome, in fact they are appreciated. >From 5181c0296dd1549e4e706ff25a4cd81a1d90137d Mon Sep 17 00:00:00 2001 From: John Kacur Date: Thu, 22 Apr 2010 17:02:42 +0200 Subject: [PATCH] lockdep: Add nr_save_trace_invocations counter Add the nr_save_trace_invocations counter which counts the number of time save_trace() is invoked when relevant for trace enteries. This means, those invocations from mark_lock() and add_lock_to_list() When called from mark_lock() we break it down into LOCKSTATE categories. Signed-off-by: John Kacur --- kernel/lockdep.c | 20 ++++++++++++++++++++ kernel/lockdep_internals.h | 2 ++ kernel/lockdep_proc.c | 23 +++++++++++++++++++++++ 3 files changed, 45 insertions(+), 0 deletions(-) diff --git a/kernel/lockdep.c b/kernel/lockdep.c index 78325f8..f921576 100644 --- a/kernel/lockdep.c +++ b/kernel/lockdep.c @@ -371,6 +371,10 @@ static int verbose(struct lock_class *class) unsigned long nr_stack_trace_entries; static unsigned long stack_trace[MAX_STACK_TRACE_ENTRIES]; +/* Calls to save_trace() from mark_lock() and add_lock_to_list() only*/ +unsigned long nr_save_trace_invocations; +unsigned long nr_save_trace_invocations_type[LOCK_USAGE_STATES]; + static int save_trace(struct stack_trace *trace) { trace->nr_entries = 0; @@ -410,6 +414,19 @@ static int save_trace(struct stack_trace *trace) return 1; } +/* + * This function is only called from mark_lock() and add_lock_to_list() + * which are only called when holding the graph_lock. This counter + * piggybacks off of that lock + */ +static void inc_save_trace_invocations(enum lock_usage_bit new_bit) +{ + nr_save_trace_invocations++; + if (WARN_ON(new_bit >= LOCK_USAGE_STATES)) + return; + nr_save_trace_invocations_type[new_bit]++; +} + unsigned int nr_hardirq_chains; unsigned int nr_softirq_chains; unsigned int nr_process_chains; @@ -449,6 +466,7 @@ static const char *usage_str[] = #define LOCKDEP_STATE(__STATE) __USAGE(__STATE) #include "lockdep_states.h" #undef LOCKDEP_STATE +#undef __USAGE [LOCK_USED] = "INITIAL USE", }; @@ -816,6 +834,7 @@ static int add_lock_to_list(struct lock_class *class, struct lock_class *this, if (!entry) return 0; + nr_save_trace_invocations++; if (!save_trace(&entry->trace)) return 0; @@ -2615,6 +2634,7 @@ static int mark_lock(struct task_struct *curr, struct held_lock *this, hlock_class(this)->usage_mask |= new_mask; + inc_save_trace_invocations(new_bit); if (!save_trace(hlock_class(this)->usage_traces + new_bit)) return 0; diff --git a/kernel/lockdep_internals.h b/kernel/lockdep_internals.h index 8d7d4b6..6149358 100644 --- a/kernel/lockdep_internals.h +++ b/kernel/lockdep_internals.h @@ -84,6 +84,8 @@ extern unsigned long nr_list_entries; extern unsigned long nr_lock_chains; extern int nr_chain_hlocks; extern unsigned long nr_stack_trace_entries; +extern unsigned long nr_save_trace_invocations; +extern unsigned long nr_save_trace_invocations_type[LOCK_USAGE_STATES]; extern unsigned int nr_hardirq_chains; extern unsigned int nr_softirq_chains; diff --git a/kernel/lockdep_proc.c b/kernel/lockdep_proc.c index 59b76c8..ef5f372 100644 --- a/kernel/lockdep_proc.c +++ b/kernel/lockdep_proc.c @@ -215,8 +215,24 @@ static void lockdep_stats_debug_show(struct seq_file *m) #endif } +#define __USAGE(__STATE) \ +[LOCK_USED_IN_##__STATE] = "LOCK_USED_IN_"__stringify(__STATE), \ +[LOCK_ENABLED_##__STATE] = "LOCK_ENABLED_"__stringify(__STATE), \ +[LOCK_USED_IN_##__STATE##_READ] = "LOCK_USED_IN_"__stringify(__STATE)"_READ", \ +[LOCK_ENABLED_##__STATE##_READ] = "LOCK_ENABLED_"__stringify(__STATE)"_READ", + +static const char *lockstate_tostr[] = +{ +#define LOCKDEP_STATE(__STATE) __USAGE(__STATE) +#include "lockdep_states.h" +#undef LOCKDEP_STATE +#undef __USAGE + [LOCK_USED] = "LOCK_USED", +}; + static int lockdep_stats_show(struct seq_file *m, void *v) { + int bit; struct lock_class *class; unsigned long nr_unused = 0, nr_uncategorized = 0, nr_irq_safe = 0, nr_irq_unsafe = 0, @@ -307,6 +323,13 @@ static int lockdep_stats_show(struct seq_file *m, void *v) nr_process_chains); seq_printf(m, " stack-trace entries: %11lu [max: %lu]\n", nr_stack_trace_entries, MAX_STACK_TRACE_ENTRIES); + seq_printf(m, " stack-trace invocations: %lu\n", + nr_save_trace_invocations); + + for (bit=0; bit < LOCK_USAGE_STATES; bit++) + seq_printf(m, "\t%s: %lu\n", lockstate_tostr[bit], + nr_save_trace_invocations_type[bit]); + seq_printf(m, " combined max dependencies: %11u\n", (nr_hardirq_chains + 1) * (nr_softirq_chains + 1) * -- 1.6.6.1 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/