From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753918AbdK0Rx4 (ORCPT ); Mon, 27 Nov 2017 12:53:56 -0500 Received: from out0-250.mail.aliyun.com ([140.205.0.250]:45103 "EHLO out0-250.mail.aliyun.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753400AbdK0Rxz (ORCPT ); Mon, 27 Nov 2017 12:53:55 -0500 X-Alimail-AntiSpam: AC=PASS;BC=-1|-1;BR=01201311R101e4;CH=green;FP=0|-1|-1|-1|0|-1|-1|-1;HT=e02c03302;MF=yang.s@alibaba-inc.com;NM=1;PH=DS;RN=3;SR=0;TI=SMTPD_---.9WLulMi_1511805219; Subject: Re: [RFC PATCH 1/2] lib: debugobjects: export max loops counter To: tglx@linutronix.de, longman@redhat.com Cc: linux-kernel@vger.kernel.org References: <1510947833-116482-1-git-send-email-yang.s@alibaba-inc.com> From: "Yang Shi" Message-ID: Date: Tue, 28 Nov 2017 01:53:30 +0800 User-Agent: Mozilla/5.0 (Macintosh; Intel Mac OS X 10.12; rv:52.0) Gecko/20100101 Thunderbird/52.2.1 MIME-Version: 1.0 In-Reply-To: <1510947833-116482-1-git-send-email-yang.s@alibaba-inc.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi Waiman & tglx, I'm not sure who is the maintainer for lib/debugobjects.c now, I'm supposed tglx still is, however, get_maintainer.pl told me Waiman is the most active developer of this, so added Waiman in this loop in case he didn't see the patches on LKML. Thanks, Yang On 11/17/17 11:43 AM, Yang Shi wrote: > 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); >