From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pf0-f176.google.com (mail-pf0-f176.google.com [209.85.192.176]) by kanga.kvack.org (Postfix) with ESMTP id 204166B0005 for ; Tue, 26 Jan 2016 19:19:20 -0500 (EST) Received: by mail-pf0-f176.google.com with SMTP id x125so1845484pfb.0 for ; Tue, 26 Jan 2016 16:19:20 -0800 (PST) Received: from lgeamrelo13.lge.com (LGEAMRELO13.lge.com. [156.147.23.53]) by mx.google.com with ESMTPS id n89si5186371pfb.138.2016.01.26.16.19.18 for (version=TLS1 cipher=ECDHE-RSA-AES128-SHA bits=128/128); Tue, 26 Jan 2016 16:19:19 -0800 (PST) Date: Wed, 27 Jan 2016 09:19:18 +0900 From: Joonsoo Kim Subject: Re: [PATCH/RFC 3/3] s390: query dynamic DEBUG_PAGEALLOC setting Message-ID: <20160127001918.GA7089@js1304-P5Q-DELUXE> References: <1453799905-10941-1-git-send-email-borntraeger@de.ibm.com> <1453799905-10941-4-git-send-email-borntraeger@de.ibm.com> <20160126181903.GB4671@osiris> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: Sender: owner-linux-mm@kvack.org List-ID: To: David Rientjes Cc: Heiko Carstens , Christian Borntraeger , linux-kernel@vger.kernel.org, akpm@linux-foundation.org, linux-mm@kvack.org, linux-arch@vger.kernel.org, linux-s390@vger.kernel.org, x86@kernel.org On Tue, Jan 26, 2016 at 03:29:38PM -0800, David Rientjes wrote: > On Tue, 26 Jan 2016, Heiko Carstens wrote: > > > On Tue, Jan 26, 2016 at 10:18:25AM +0100, Christian Borntraeger wrote: > > > We can use debug_pagealloc_enabled() to check if we can map > > > the identity mapping with 1MB/2GB pages as well as to print > > > the current setting in dump_stack. > > > > > > Signed-off-by: Christian Borntraeger > > > --- > > > arch/s390/kernel/dumpstack.c | 4 +++- > > > arch/s390/mm/vmem.c | 10 ++++------ > > > 2 files changed, 7 insertions(+), 7 deletions(-) > > > > > > diff --git a/arch/s390/kernel/dumpstack.c b/arch/s390/kernel/dumpstack.c > > > index dc8e204..a1c0530 100644 > > > --- a/arch/s390/kernel/dumpstack.c > > > +++ b/arch/s390/kernel/dumpstack.c > > > @@ -11,6 +11,7 @@ > > > #include > > > #include > > > #include > > > +#include > > > #include > > > #include > > > #include > > > @@ -186,7 +187,8 @@ void die(struct pt_regs *regs, const char *str) > > > printk("SMP "); > > > #endif > > > #ifdef CONFIG_DEBUG_PAGEALLOC > > > - printk("DEBUG_PAGEALLOC"); > > > + printk("DEBUG_PAGEALLOC(%s)", > > > + debug_pagealloc_enabled() ? "enabled" : "disabled"); > > > #endif > > > > I'd prefer if you change this to > > > > if (debug_pagealloc_enabled()) > > printk("DEBUG_PAGEALLOC"); > > > > That way we can get rid of yet another ifdef. Having > > "DEBUG_PAGEALLOC(disabled)" doesn't seem to be very helpful. > > > > I'd agree if CONFIG_DEBUG_PAGEALLOC only did anything when > debug_pagealloc_enabled() is true, but that doesn't seem to be the case. > When CONFIG_DEBUG_SLAB is enabled, for instance, CONFIG_DEBUG_PAGEALLOC > also enables stackinfo storing and poisoning and it's not guarded by > debug_pagealloc_enabled(). > > It seems like CONFIG_DEBUG_PAGEALLOC enables debugging functionality > outside the scope of the debug_pagealloc=on kernel parameter, so > DEBUG_PAGEALLOC(disabled) actually does mean something. Hello, David. I tried to fix CONFIG_DEBUG_SLAB case on 04/16 of following patchset. http://thread.gmane.org/gmane.linux.kernel.mm/144527 I found that there are more sites to fix but not so many. We can do it. Thanks. -- 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: email@kvack.org