From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=u9Ay=KN=lists.01.org=linux-nvdimm-bounces@kernel.org>
X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on
	aws-us-west-2-korg-lkml-1.web.codeaurora.org
X-Spam-Level: 
X-Spam-Status: No, score=-5.1 required=3.0 tests=BAYES_00,DKIM_INVALID,
	DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,NICE_REPLY_A,
	SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 autolearn=no autolearn_force=no
	version=3.4.0
Received: from mail.kernel.org (mail.kernel.org [198.145.29.99])
	by smtp.lore.kernel.org (Postfix) with ESMTP id 38FFDC43470
	for <linux-nvdimm@archiver.kernel.org>; Tue, 18 May 2021 10:06:55 +0000 (UTC)
Received: from ml01.01.org (ml01.01.org [198.145.21.10])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by mail.kernel.org (Postfix) with ESMTPS id D9D9960725
	for <linux-nvdimm@archiver.kernel.org>; Tue, 18 May 2021 10:06:53 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D9D9960725
Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com
Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-nvdimm-bounces@lists.01.org
Received: from ml01.vlan13.01.org (localhost [IPv6:::1])
	by ml01.01.org (Postfix) with ESMTP id ABE3B100EB358;
	Tue, 18 May 2021 03:06:53 -0700 (PDT)
Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=170.10.133.124; helo=us-smtp-delivery-124.mimecast.com; envelope-from=david@redhat.com; receiver=<UNKNOWN> 
Received: from us-smtp-delivery-124.mimecast.com (us-smtp-delivery-124.mimecast.com [170.10.133.124])
	(using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits))
	(No client certificate requested)
	by ml01.01.org (Postfix) with ESMTPS id 26831100EB350
	for <linux-nvdimm@lists.01.org>; Tue, 18 May 2021 03:06:50 -0700 (PDT)
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com;
	s=mimecast20190719; t=1621332409;
	h=from:from:reply-to:subject:subject:date:date:message-id:message-id:
	 to:to:cc:cc:mime-version:mime-version:content-type:content-type:
	 content-transfer-encoding:content-transfer-encoding:
	 in-reply-to:in-reply-to:references:references;
	bh=dFkmeu2athwSt2LK0RUUi/E/grHFe/dKRRuvCpK8qJo=;
	b=XEcE8fBbLoLU6ZJirZ8BoG9FTYmuyIQvP5iUQM92lmYipET+JAp1Th2aixoxs0P1qPa4xN
	V92AOvN5YQ4RmFoBIGWURT4IhOdQfMjJjJM7r9SQWfWKmf/rI1qd+js7fgy9mozOPDOm21
	/2aEjMhK7qyowuN7cffnKG8R+GVYqko=
Received: from mail-wr1-f70.google.com (mail-wr1-f70.google.com
 [209.85.221.70]) (Using TLS) by relay.mimecast.com with ESMTP id
 us-mta-380-A4NLYjIWNpGOpKH293PghQ-1; Tue, 18 May 2021 06:06:47 -0400
X-MC-Unique: A4NLYjIWNpGOpKH293PghQ-1
Received: by mail-wr1-f70.google.com with SMTP id d12-20020adfc3cc0000b029011166e2f1a7so4393101wrg.19
        for <linux-nvdimm@lists.01.org>; Tue, 18 May 2021 03:06:47 -0700 (PDT)
X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed;
        d=1e100.net; s=20161025;
        h=x-gm-message-state:subject:to:cc:references:from:organization
         :message-id:date:user-agent:mime-version:in-reply-to
         :content-language:content-transfer-encoding;
        bh=dFkmeu2athwSt2LK0RUUi/E/grHFe/dKRRuvCpK8qJo=;
        b=DacSD9YacreUfviyWHRIX8Hi98HuA5q/ckzY3jy8lFak7QZJ04E4cUlGq/xAGxqGlk
         OTFVh66yCSzI8ocSW4YrfVVMNXi7+7ce6wlcYjhjNq+oObNRfCdRDSeqwDlb2NIXyGCk
         Z79Nb80fFfzKiZ1KlA0WzgCli4I68CsorxxCDno5EHGqI6CBGnGsZN1gsoPT0WAT1IPp
         6n7E6InLiw++DoJFq8AWsseH476Ugqtf4KTn48gnFKKD4dUYnJc9ok1sPUHYS9AoIvXS
         idNzkVXRJFfffT3N8aZeBQy6O98k7RQhUKY7scnjSwaZuNFmoyr7afQaWZlgWMNGL2v7
         1kow==
X-Gm-Message-State: AOAM530O+UHDrgNRVJfMI+lZ+VOX+f3cvUWiQtyZXAqj4zovvFOCUuxI
	Fkdn2SwV5jOAqsFcV3SXzRcWHs1WmTNyli81xz43EbM2jJ7E6HYFS+OlrF8E2TwFoqskmRxS3FU
	S67Ef9HBvb7B/8+u/gomK
X-Received: by 2002:a05:6000:1ac5:: with SMTP id i5mr5879978wry.6.1621332406615;
        Tue, 18 May 2021 03:06:46 -0700 (PDT)
X-Google-Smtp-Source: ABdhPJwiVxI2VqHM3UC3HkCv7YVP9ChZhf/paSvmhTbK/1R/b2aClM7EAkaKYj9OwIH5AzvG3tEX6Q==
X-Received: by 2002:a05:6000:1ac5:: with SMTP id i5mr5879787wry.6.1621332405164;
        Tue, 18 May 2021 03:06:45 -0700 (PDT)
Received: from [192.168.3.132] (p5b0c64fd.dip0.t-ipconnect.de. [91.12.100.253])
        by smtp.gmail.com with ESMTPSA id f14sm8395872wry.40.2021.05.18.03.06.43
        (version=TLS1_3 cipher=TLS_AES_128_GCM_SHA256 bits=128/128);
        Tue, 18 May 2021 03:06:44 -0700 (PDT)
Subject: Re: [PATCH v19 5/8] mm: introduce memfd_secret system call to create
 "secret" memory areas
To: Michal Hocko <mhocko@suse.com>, Mike Rapoport <rppt@kernel.org>
References: <20210513184734.29317-1-rppt@kernel.org>
 <20210513184734.29317-6-rppt@kernel.org>
 <b625c5d7-bfcc-9e95-1f79-fc8b61498049@redhat.com>
 <YKDJ1L7XpJRQgSch@kernel.org> <YKOP5x8PPbqzcsdK@dhcp22.suse.cz>
From: David Hildenbrand <david@redhat.com>
Organization: Red Hat
Message-ID: <8e114f09-60e4-2343-1c42-1beaf540c150@redhat.com>
Date: Tue, 18 May 2021 12:06:42 +0200
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:78.0) Gecko/20100101
 Thunderbird/78.10.1
MIME-Version: 1.0
In-Reply-To: <YKOP5x8PPbqzcsdK@dhcp22.suse.cz>
Authentication-Results: relay.mimecast.com;
	auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=david@redhat.com
X-Mimecast-Spam-Score: 0
X-Mimecast-Originator: redhat.com
Content-Language: en-US
Message-ID-Hash: IWHMERSPA5V6IV5MGGDCYUZLBMFFOXV6
X-Message-ID-Hash: IWHMERSPA5V6IV5MGGDCYUZLBMFFOXV6
X-MailFrom: david@redhat.com
X-Mailman-Rule-Hits: nonmember-moderation
X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation
CC: Andrew Morton <akpm@linux-foundation.org>, Alexander Viro <viro@zeniv.linux.org.uk>, Andy Lutomirski <luto@kernel.org>, Arnd Bergmann <arnd@arndb.de>, Borislav Petkov <bp@alien8.de>, Catalin Marinas <catalin.marinas@arm.com>, Christopher Lameter <cl@linux.com>, Dave Hansen <dave.hansen@linux.intel.com>, Elena Reshetova <elena.reshetova@intel.com>, "H. Peter Anvin" <hpa@zytor.com>, Hagen Paul Pfeifer <hagen@jauu.net>, Ingo Molnar <mingo@redhat.com>, James Bottomley <jejb@linux.ibm.com>, Kees Cook <keescook@chromium.org>, "Kirill A. Shutemov" <kirill@shutemov.name>, Matthew Wilcox <willy@infradead.org>, Matthew Garrett <mjg59@srcf.ucam.org>, Mark Rutland <mark.rutland@arm.com>, Mike Rapoport <rppt@linux.ibm.com>, Michael Kerrisk <mtk.manpages@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Palmer Dabbelt <palmerdabbelt@google.com>, Paul Walmsley <paul.walmsley@sifive.com>, Peter Zijlstra <peterz@infradead.org>, "Rafael J. Wysocki" <rjw@rjwysocki.net>, Rick Edgecombe <rick.p.edgeco
 mbe@intel.com>, Roman Gushchin <guro@fb.com>, Shakeel Butt <shakeelb@google.com>, Shuah Khan <shuah@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Tycho Andersen <tycho@tycho.ws>, Will Deacon <will@kernel.org>, Yury Norov <yury.norov@gmail.com>, linux-api@vger.kernel.org, linux-arch@vger.kernel.org, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-nvdimm@lists.01.org, linux-riscv@lists.infradead.org, x86@kernel.org
X-Mailman-Version: 3.1.1
Precedence: list
List-Id: "Linux-nvdimm developer list." <linux-nvdimm.lists.01.org>
Archived-At: <https://lists.01.org/hyperkitty/list/linux-nvdimm@lists.01.org/message/IWHMERSPA5V6IV5MGGDCYUZLBMFFOXV6/>
List-Archive: <https://lists.01.org/hyperkitty/list/linux-nvdimm@lists.01.org/>
List-Help: <mailto:linux-nvdimm-request@lists.01.org?subject=help>
List-Post: <mailto:linux-nvdimm@lists.01.org>
List-Subscribe: <mailto:linux-nvdimm-join@lists.01.org>
List-Unsubscribe: <mailto:linux-nvdimm-leave@lists.01.org>
Content-Type: text/plain; charset="us-ascii"; format="flowed"
Content-Transfer-Encoding: 7bit

On 18.05.21 11:59, Michal Hocko wrote:
> On Sun 16-05-21 10:29:24, Mike Rapoport wrote:
>> On Fri, May 14, 2021 at 11:25:43AM +0200, David Hildenbrand wrote:
> [...]
>>>> +		if (!page)
>>>> +			return VM_FAULT_OOM;
>>>> +
>>>> +		err = set_direct_map_invalid_noflush(page, 1);
>>>> +		if (err) {
>>>> +			put_page(page);
>>>> +			return vmf_error(err);
>>>
>>> Would we want to translate that to a proper VM_FAULT_..., which would most
>>> probably be VM_FAULT_OOM when we fail to allocate a pagetable?
>>
>> That's what vmf_error does, it translates -ESOMETHING to VM_FAULT_XYZ.
> 
> I haven't read through the rest but this has just caught my attention.
> Is it really reasonable to trigger the oom killer when you cannot
> invalidate the direct mapping. From a quick look at the code it is quite
> unlikely to se ENOMEM from that path (it allocates small pages) but this
> can become quite sublte over time. Shouldn't this simply SIGBUS if it
> cannot manipulate the direct mapping regardless of the underlying reason
> for that?
> 

OTOH, it means our kernel zones are depleted, so we'd better reclaim 
somehow ...

-- 
Thanks,

David / dhildenb
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org