From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S935345AbdKQToP (ORCPT ); Fri, 17 Nov 2017 14:44:15 -0500 Received: from out0-236.mail.aliyun.com ([140.205.0.236]:55358 "EHLO out0-236.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751362AbdKQToG (ORCPT ); Fri, 17 Nov 2017 14:44:06 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R581e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e02c03278;MF=yang.s@alibaba-inc.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---.9RBXktw_1510947833; From: "Yang Shi" To: tglx@linutronix.de Cc: "Yang Shi" , Subject: [RFC PATCH 1/2] lib: debugobjects: export max loops counter Date: Sat, 18 Nov 2017 03:43:52 +0800 Message-Id: <1510947833-116482-1-git-send-email-yang.s@alibaba-inc.com> X-Mailer: git-send-email 1.8.3.1 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Currently max chain counter is exported to sysfs, it just record the counter of inner loop, however, there might be significant iterations of external loop then it may take significant amount of time to finish all of the checks. This may cuase lockup on !CONFIG_PREEMPT kernel build occasionally. Record the counter of the max loops then export to sysfs so that the user can be aware of the real overhead. Then the output of /sys/kernel/debug/debug_objects/stats looks like: max_chain :121 max_loops :543267 warnings :0 fixups :0 pool_free :1764 pool_min_free :341 pool_used :86438 pool_max_used :268887 objs_allocated:6068254 objs_freed :5981076 Signed-off-by: Yang Shi --- lib/debugobjects.c | 9 ++++++++- 1 file changed, 8 insertions(+), 1 deletion(-) diff --git a/lib/debugobjects.c b/lib/debugobjects.c index 2f5349c..166488d 100644 --- a/lib/debugobjects.c +++ b/lib/debugobjects.c @@ -50,6 +50,7 @@ struct debug_bucket { static struct kmem_cache *obj_cache; static int debug_objects_maxchain __read_mostly; +static int debug_objects_maxloops __read_mostly; static int debug_objects_fixups __read_mostly; static int debug_objects_warnings __read_mostly; static int debug_objects_enabled __read_mostly @@ -720,7 +721,7 @@ static void __debug_check_no_obj_freed(const void *address, unsigned long size) enum debug_obj_state state; struct debug_bucket *db; struct debug_obj *obj; - int cnt; + int cnt, max_loops = 0; saddr = (unsigned long) address; eaddr = saddr + size; @@ -765,7 +766,12 @@ static void __debug_check_no_obj_freed(const void *address, unsigned long size) if (cnt > debug_objects_maxchain) debug_objects_maxchain = cnt; + + max_loops += cnt; } + + if (max_loops > debug_objects_maxloops) + debug_objects_maxloops = max_loops; } void debug_check_no_obj_freed(const void *address, unsigned long size) @@ -780,6 +786,7 @@ void debug_check_no_obj_freed(const void *address, unsigned long size) static int debug_stats_show(struct seq_file *m, void *v) { seq_printf(m, "max_chain :%d\n", debug_objects_maxchain); + seq_printf(m, "max_loops :%d\n", debug_objects_maxloops); seq_printf(m, "warnings :%d\n", debug_objects_warnings); seq_printf(m, "fixups :%d\n", debug_objects_fixups); seq_printf(m, "pool_free :%d\n", obj_pool_free); -- 1.8.3.1