From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-oi0-f69.google.com (mail-oi0-f69.google.com [209.85.218.69]) by kanga.kvack.org (Postfix) with ESMTP id 3D4A56B0253 for ; Fri, 24 Nov 2017 09:39:25 -0500 (EST) Received: by mail-oi0-f69.google.com with SMTP id f68so8063601oig.3 for ; Fri, 24 Nov 2017 06:39:25 -0800 (PST) Received: from mail-sor-f65.google.com (mail-sor-f65.google.com. [209.85.220.65]) by mx.google.com with SMTPS id i205sor6279111oia.189.2017.11.24.06.39.24 for (Google Transport Security); Fri, 24 Nov 2017 06:39:24 -0800 (PST) MIME-Version: 1.0 In-Reply-To: <4e21a27570f665793debf167c8567c6752116d0a.1511433386.git.ar@linux.vnet.ibm.com> References: <4e21a27570f665793debf167c8567c6752116d0a.1511433386.git.ar@linux.vnet.ibm.com> From: "Rafael J. Wysocki" Date: Fri, 24 Nov 2017 15:39:23 +0100 Message-ID: Subject: Re: [PATCH v2 2/5] mm: memory_hotplug: Remove assumption on memory state before hotremove Content-Type: text/plain; charset="UTF-8" Sender: owner-linux-mm@kvack.org List-ID: To: Andrea Reale Cc: "linux-arm-kernel@lists.infradead.org" , Linux Kernel Mailing List , Linux Memory Management List , m.bielski@virtualopensystems.com, arunks@qti.qualcomm.com, Mark Rutland , scott.branden@broadcom.com, Will Deacon , qiuxishi@huawei.com, Catalin Marinas , Michal Hocko , Rafael Wysocki , ACPI Devel Maling List On Fri, Nov 24, 2017 at 11:22 AM, Andrea Reale wrote: > Resending the patch adding linux-acpi in CC, as suggested by Rafael. > Everyone else: apologies for the noise. > > Commit 242831eb15a0 ("Memory hotplug / ACPI: Simplify memory removal") > introduced an assumption whereas when control > reaches remove_memory the corresponding memory has been already > offlined. In that case, the acpi_memhotplug was making sure that > the assumption held. > This assumption, however, is not necessarily true if offlining > and removal are not done by the same "controller" (for example, > when first offlining via sysfs). > > Removing this assumption for the generic remove_memory code > and moving it in the specific acpi_memhotplug code. This is > a dependency for the software-aided arm64 offlining and removal > process. > > Signed-off-by: Andrea Reale > Signed-off-by: Maciej Bielski > --- > drivers/acpi/acpi_memhotplug.c | 2 +- > include/linux/memory_hotplug.h | 9 ++++++--- > mm/memory_hotplug.c | 13 +++++++++---- > 3 files changed, 16 insertions(+), 8 deletions(-) > > diff --git a/drivers/acpi/acpi_memhotplug.c b/drivers/acpi/acpi_memhotplug.c > index 6b0d3ef..b0126a0 100644 > --- a/drivers/acpi/acpi_memhotplug.c > +++ b/drivers/acpi/acpi_memhotplug.c > @@ -282,7 +282,7 @@ static void acpi_memory_remove_memory(struct acpi_memory_device *mem_device) > nid = memory_add_physaddr_to_nid(info->start_addr); > > acpi_unbind_memory_blocks(info); > - remove_memory(nid, info->start_addr, info->length); > + BUG_ON(remove_memory(nid, info->start_addr, info->length)); Why does this have to be BUG_ON()? Is it really necessary to kill the system here? If it is, please add a comment describing why continuing is not an option here. > list_del(&info->list); > kfree(info); > } Thanks, Rafael -- 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