From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-io1-f71.google.com (mail-io1-f71.google.com [209.85.166.71]) by kanga.kvack.org (Postfix) with ESMTP id 98AD08E0001 for ; Fri, 21 Sep 2018 15:41:23 -0400 (EDT) Received: by mail-io1-f71.google.com with SMTP id x5-v6so24435620ioa.6 for ; Fri, 21 Sep 2018 12:41:23 -0700 (PDT) Received: from ale.deltatee.com (ale.deltatee.com. [207.54.116.67]) by mx.google.com with ESMTPS id p65-v6si18126892iop.187.2018.09.21.12.41.22 for (version=TLS1_2 cipher=ECDHE-RSA-CHACHA20-POLY1305 bits=256/256); Fri, 21 Sep 2018 12:41:22 -0700 (PDT) References: <20180920215824.19464.8884.stgit@localhost.localdomain> <20180920222415.19464.38400.stgit@localhost.localdomain> From: Logan Gunthorpe Message-ID: <4d984974-ff16-35e4-76ff-f5e43e5e90da@deltatee.com> Date: Fri, 21 Sep 2018 13:41:12 -0600 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 Content-Language: en-US Content-Transfer-Encoding: 7bit Subject: Re: [PATCH v4 1/5] mm: Provide kernel parameter to allow disabling page init poisoning Sender: owner-linux-mm@kvack.org List-ID: To: Pasha Tatashin , Alexander Duyck , "linux-mm@kvack.org" , "linux-kernel@vger.kernel.org" , "linux-nvdimm@lists.01.org" Cc: "mhocko@suse.com" , "dave.jiang@intel.com" , "mingo@kernel.org" , "dave.hansen@intel.com" , "jglisse@redhat.com" , "akpm@linux-foundation.org" , "dan.j.williams@intel.com" , "kirill.shutemov@linux.intel.com" On 2018-09-21 1:04 PM, Pasha Tatashin wrote: > >> + pr_err("vm_debug option '%c' unknown. skipped\n", >> + *str); >> + } >> + >> + str++; >> + } >> +out: >> + if (page_init_poisoning && !__page_init_poisoning) >> + pr_warn("Page struct poisoning disabled by kernel command line option 'vm_debug'\n"); > > New lines '\n' can be removed, they are not needed for kprintfs. No, that's not correct. A printk without a newline termination is not emitted as output until the next printk call. (To support KERN_CONT). Therefore removing the '\n' causes a printk to not be printed when it is called which can cause long delayed messages and subtle problems when debugging. Always keep the newline in place even though the kernel will add one for you if it's missing. Logan