From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=BnL6=G7=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=-3.5 required=3.0 tests=BAYES_00,DKIM_INVALID,
	DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,
	SPF_PASS,URIBL_BLOCKED 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 4CE55C433DB
	for <linux-nvdimm@archiver.kernel.org>; Thu, 28 Jan 2021 13:49:41 +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 DE84D64DD9
	for <linux-nvdimm@archiver.kernel.org>; Thu, 28 Jan 2021 13:49:40 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org DE84D64DD9
Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.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 8FE2A100EB32C;
	Thu, 28 Jan 2021 05:49:40 -0800 (PST)
Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=195.135.220.15; helo=mx2.suse.de; envelope-from=mhocko@suse.com; receiver=<UNKNOWN> 
Received: from mx2.suse.de (mx2.suse.de [195.135.220.15])
	(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 9C1E3100EB855
	for <linux-nvdimm@lists.01.org>; Thu, 28 Jan 2021 05:49:37 -0800 (PST)
X-Virus-Scanned: by amavisd-new at test-mx.suse.de
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1;
	t=1611841775; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:
	 mime-version:mime-version:content-type:content-type:
	 in-reply-to:in-reply-to:references:references;
	bh=75llh3uw6L6UpTgmVsHlz+i8LHZJ84jNMGnauBZqITc=;
	b=RFEQmGK/LljkSM2oiWx77CIGoV0eKNOaEQIEAkrhzpN9jbb3MOKURRCYaRwYVt6/w/U/+e
	g4VVantqh8P7n2dKzYTMYQk4w9MXZKXSASL6hjd+n4xFytPepUsla6MMacf9DtnSP1AmZ/
	v2BcnFvMM+kSY0c0Ye3UOYH/R63VQ8Q=
Received: from relay2.suse.de (unknown [195.135.221.27])
	by mx2.suse.de (Postfix) with ESMTP id 9E752AF78;
	Thu, 28 Jan 2021 13:49:35 +0000 (UTC)
Date: Thu, 28 Jan 2021 14:49:34 +0100
From: Michal Hocko <mhocko@suse.com>
To: Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize
 direct map fragmentation
Message-ID: <YBLA7sEKn01HXd/U@dhcp22.suse.cz>
References: <20210121122723.3446-1-rppt@kernel.org>
 <20210121122723.3446-8-rppt@kernel.org>
 <20210126114657.GL827@dhcp22.suse.cz>
 <303f348d-e494-e386-d1f5-14505b5da254@redhat.com>
 <20210126120823.GM827@dhcp22.suse.cz>
 <20210128092259.GB242749@kernel.org>
 <YBK1kqL7JA7NePBQ@dhcp22.suse.cz>
 <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
Message-ID-Hash: NPTJ3PHCRD6NLYT5F6UQ3Q5LGHMEYI3H
X-Message-ID-Hash: NPTJ3PHCRD6NLYT5F6UQ3Q5LGHMEYI3H
X-MailFrom: mhocko@suse.com
X-Mailman-Rule-Hits: nonmember-moderation
X-Mailman-Rule-Misses: dmarc-mitigation; no-senders; approved; emergency; loop; banned-address; member-moderation
CC: Mike Rapoport <rppt@kernel.org>, David Hildenbrand <david@redhat.com>, 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>, Dave Hansen <dave.hansen@linux.intel.com>, Elena Reshetova <elena.reshetova@intel.com>, "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>, James Bottomley <jejb@linux.ibm.com>, "Kirill A. Shutemov" <kirill@shutemov.name>, Matthew Wilcox <willy@infradead.org>, Mark Rutland <mark.rutland@arm.com>, Mike Rapoport <rppt@linux.ibm.com>, Michael Kerrisk <mtk.manpages@gmail.com>, Palmer Dabbelt <palmer@dabbelt.com>, Paul Walmsley <paul.walmsley@sifive.com>, Peter Zijlstra <peterz@infradead.org>, Rick Edgecombe <rick.p.edgecombe@intel.com>, Roman Gushchin <guro@fb.com>, Shakeel Butt <shakeelb@google.com>, Shuah Khan <shuah@kernel.org>, Thomas Gleixner <tglx@linutronix.de>, Tycho And
 ersen <tycho@tycho.ws>, Will Deacon <will@kernel.org>, 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, Hagen Paul Pfeifer <hagen@jauu.net>, Palmer Dabbelt <palmerdabbelt@google.com>
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/NPTJ3PHCRD6NLYT5F6UQ3Q5LGHMEYI3H/>
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"
Content-Transfer-Encoding: 7bit

On Thu 28-01-21 13:28:10, Cristopher Lameter wrote:
> On Thu, 28 Jan 2021, Michal Hocko wrote:
> 
> > > So, if I understand your concerns correct this implementation has two
> > > issues:
> > > 1) allocation failure at page fault that causes unrecoverable OOM and
> > > 2) a possibility for an unprivileged user to deplete secretmem pool and
> > > cause (1) to others
> > >
> > > I'm not really familiar with OOM internals, but when I simulated an
> > > allocation failure in my testing only the allocating process and it's
> > > parent were OOM-killed and then the system continued normally.
> >
> > If you kill the allocating process then yes, it would work, but your
> > process might be the very last to be selected.
> 
> OOMs are different if you have a "constrained allocation". In that case it
> is the fault of the process who wanted memory with certain conditions.
> That memory is not available. General memory is available though. In that
> case the allocating process is killed.

I do not see this implementation would do anything like that. Neither
anything like that implemented in the oom killer. Constrained
allocations (cpusets/memcg/mempolicy) only do restrict their selection
to processes which belong to the same domain. So I am not really sure
what you are referring to. The is only a global knob to _always_ kill
the allocating process on OOM.

-- 
Michal Hocko
SUSE Labs
_______________________________________________
Linux-nvdimm mailing list -- linux-nvdimm@lists.01.org
To unsubscribe send an email to linux-nvdimm-leave@lists.01.org

From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@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=-5.8 required=3.0 tests=BAYES_00,DKIM_SIGNED,
	DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,
	SPF_HELO_NONE,SPF_PASS 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 B852AC433E6
	for <linux-kernel@archiver.kernel.org>; Thu, 28 Jan 2021 13:50:26 +0000 (UTC)
Received: from vger.kernel.org (vger.kernel.org [23.128.96.18])
	by mail.kernel.org (Postfix) with ESMTP id 7A90164DD8
	for <linux-kernel@archiver.kernel.org>; Thu, 28 Jan 2021 13:50:26 +0000 (UTC)
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
        id S231252AbhA1NuZ (ORCPT <rfc822;linux-kernel@archiver.kernel.org>);
        Thu, 28 Jan 2021 08:50:25 -0500
Received: from mx2.suse.de ([195.135.220.15]:37626 "EHLO mx2.suse.de"
        rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP
        id S229811AbhA1NuW (ORCPT <rfc822;linux-kernel@vger.kernel.org>);
        Thu, 28 Jan 2021 08:50:22 -0500
X-Virus-Scanned: by amavisd-new at test-mx.suse.de
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1;
        t=1611841775; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:
         mime-version:mime-version:content-type:content-type:
         in-reply-to:in-reply-to:references:references;
        bh=75llh3uw6L6UpTgmVsHlz+i8LHZJ84jNMGnauBZqITc=;
        b=RFEQmGK/LljkSM2oiWx77CIGoV0eKNOaEQIEAkrhzpN9jbb3MOKURRCYaRwYVt6/w/U/+e
        g4VVantqh8P7n2dKzYTMYQk4w9MXZKXSASL6hjd+n4xFytPepUsla6MMacf9DtnSP1AmZ/
        v2BcnFvMM+kSY0c0Ye3UOYH/R63VQ8Q=
Received: from relay2.suse.de (unknown [195.135.221.27])
        by mx2.suse.de (Postfix) with ESMTP id 9E752AF78;
        Thu, 28 Jan 2021 13:49:35 +0000 (UTC)
Date:   Thu, 28 Jan 2021 14:49:34 +0100
From:   Michal Hocko <mhocko@suse.com>
To:     Christoph Lameter <cl@linux.com>
Cc:     Mike Rapoport <rppt@kernel.org>,
        David Hildenbrand <david@redhat.com>,
        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>,
        Dan Williams <dan.j.williams@intel.com>,
        Dave Hansen <dave.hansen@linux.intel.com>,
        Elena Reshetova <elena.reshetova@intel.com>,
        "H. Peter Anvin" <hpa@zytor.com>, Ingo Molnar <mingo@redhat.com>,
        James Bottomley <jejb@linux.ibm.com>,
        "Kirill A. Shutemov" <kirill@shutemov.name>,
        Matthew Wilcox <willy@infradead.org>,
        Mark Rutland <mark.rutland@arm.com>,
        Mike Rapoport <rppt@linux.ibm.com>,
        Michael Kerrisk <mtk.manpages@gmail.com>,
        Palmer Dabbelt <palmer@dabbelt.com>,
        Paul Walmsley <paul.walmsley@sifive.com>,
        Peter Zijlstra <peterz@infradead.org>,
        Rick Edgecombe <rick.p.edgecombe@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>,
        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, Hagen Paul Pfeifer <hagen@jauu.net>,
        Palmer Dabbelt <palmerdabbelt@google.com>
Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize
 direct map fragmentation
Message-ID: <YBLA7sEKn01HXd/U@dhcp22.suse.cz>
References: <20210121122723.3446-1-rppt@kernel.org>
 <20210121122723.3446-8-rppt@kernel.org>
 <20210126114657.GL827@dhcp22.suse.cz>
 <303f348d-e494-e386-d1f5-14505b5da254@redhat.com>
 <20210126120823.GM827@dhcp22.suse.cz>
 <20210128092259.GB242749@kernel.org>
 <YBK1kqL7JA7NePBQ@dhcp22.suse.cz>
 <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
MIME-Version: 1.0
Content-Type: text/plain; charset=us-ascii
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
Precedence: bulk
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On Thu 28-01-21 13:28:10, Cristopher Lameter wrote:
> On Thu, 28 Jan 2021, Michal Hocko wrote:
> 
> > > So, if I understand your concerns correct this implementation has two
> > > issues:
> > > 1) allocation failure at page fault that causes unrecoverable OOM and
> > > 2) a possibility for an unprivileged user to deplete secretmem pool and
> > > cause (1) to others
> > >
> > > I'm not really familiar with OOM internals, but when I simulated an
> > > allocation failure in my testing only the allocating process and it's
> > > parent were OOM-killed and then the system continued normally.
> >
> > If you kill the allocating process then yes, it would work, but your
> > process might be the very last to be selected.
> 
> OOMs are different if you have a "constrained allocation". In that case it
> is the fault of the process who wanted memory with certain conditions.
> That memory is not available. General memory is available though. In that
> case the allocating process is killed.

I do not see this implementation would do anything like that. Neither
anything like that implemented in the oom killer. Constrained
allocations (cpusets/memcg/mempolicy) only do restrict their selection
to processes which belong to the same domain. So I am not really sure
what you are referring to. The is only a global knob to _always_ kill
the allocating process on OOM.

-- 
Michal Hocko
SUSE Labs

From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=TFiT=G7=lists.infradead.org=linux-riscv-bounces+linux-riscv=archiver.kernel.org@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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH,
	DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,
	SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 234FBC433DB
	for <linux-riscv@archiver.kernel.org>; Thu, 28 Jan 2021 13:49:54 +0000 (UTC)
Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134])
	(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 AA44464DD6
	for <linux-riscv@archiver.kernel.org>; Thu, 28 Jan 2021 13:49:53 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AA44464DD6
Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com
Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
	d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding:
	Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive:
	List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID:
	Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:
	Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner;
	 bh=w4Jx8tCXYd9mvqs/iAqsAVCxNToFPKeJ8ZtRNEZTlWs=; b=PDHvvUg6Nn1yNrRnc4LB1AmIz
	bc6bl+JxGuBFEgclwxZPW2T/e43flSZ39wd0vpplutfipMzuHYv+VdF5eKp7KLR7MUyAnYYFVw1xq
	0Qmdy99efD0Y7Ld5U0wRPji59abRjb1FlpMoToiydEyARfct3sD3/TW51pPncBLZxtxcKltok5qzc
	m/7uwZPipNgt1emSTS9PW5nB7zqL5JXdwo8Gz+Zrg0pxe32YYZusv9R2L6TsRgYuhZXPwSP/m6ntq
	3mOmSbR9oIQoL2UQts7TbiSphplgyHjaISDRTaTFXGRPxdWeZ2T5sZipEzaFIAgyDCcp2oRHD+BPT
	ouv6pDJ9A==;
Received: from localhost ([::1] helo=merlin.infradead.org)
	by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux))
	id 1l57g5-0002yY-DO; Thu, 28 Jan 2021 13:49:41 +0000
Received: from mx2.suse.de ([195.135.220.15])
 by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux))
 id 1l57g1-0002xE-0H; Thu, 28 Jan 2021 13:49:38 +0000
X-Virus-Scanned: by amavisd-new at test-mx.suse.de
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1;
 t=1611841775; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:
 mime-version:mime-version:content-type:content-type:
 in-reply-to:in-reply-to:references:references;
 bh=75llh3uw6L6UpTgmVsHlz+i8LHZJ84jNMGnauBZqITc=;
 b=RFEQmGK/LljkSM2oiWx77CIGoV0eKNOaEQIEAkrhzpN9jbb3MOKURRCYaRwYVt6/w/U/+e
 g4VVantqh8P7n2dKzYTMYQk4w9MXZKXSASL6hjd+n4xFytPepUsla6MMacf9DtnSP1AmZ/
 v2BcnFvMM+kSY0c0Ye3UOYH/R63VQ8Q=
Received: from relay2.suse.de (unknown [195.135.221.27])
 by mx2.suse.de (Postfix) with ESMTP id 9E752AF78;
 Thu, 28 Jan 2021 13:49:35 +0000 (UTC)
Date: Thu, 28 Jan 2021 14:49:34 +0100
From: Michal Hocko <mhocko@suse.com>
To: Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize
 direct map fragmentation
Message-ID: <YBLA7sEKn01HXd/U@dhcp22.suse.cz>
References: <20210121122723.3446-1-rppt@kernel.org>
 <20210121122723.3446-8-rppt@kernel.org>
 <20210126114657.GL827@dhcp22.suse.cz>
 <303f348d-e494-e386-d1f5-14505b5da254@redhat.com>
 <20210126120823.GM827@dhcp22.suse.cz>
 <20210128092259.GB242749@kernel.org>
 <YBK1kqL7JA7NePBQ@dhcp22.suse.cz>
 <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 
X-CRM114-CacheID: sfid-20210128_084937_387188_FCF55189 
X-CRM114-Status: GOOD (  21.60  )
X-BeenThere: linux-riscv@lists.infradead.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <linux-riscv.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-riscv>,
 <mailto:linux-riscv-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-riscv/>
List-Post: <mailto:linux-riscv@lists.infradead.org>
List-Help: <mailto:linux-riscv-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-riscv>,
 <mailto:linux-riscv-request@lists.infradead.org?subject=subscribe>
Cc: Mark Rutland <mark.rutland@arm.com>, David Hildenbrand <david@redhat.com>,
 Peter Zijlstra <peterz@infradead.org>,
 Catalin Marinas <catalin.marinas@arm.com>,
 Dave Hansen <dave.hansen@linux.intel.com>, linux-mm@kvack.org,
 linux-kselftest@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
 linux-riscv@lists.infradead.org, Shuah Khan <shuah@kernel.org>,
 Thomas Gleixner <tglx@linutronix.de>,
 Elena Reshetova <elena.reshetova@intel.com>, linux-arch@vger.kernel.org,
 Tycho Andersen <tycho@tycho.ws>, linux-nvdimm@lists.01.org,
 Will Deacon <will@kernel.org>, x86@kernel.org,
 Matthew Wilcox <willy@infradead.org>, Mike Rapoport <rppt@linux.ibm.com>,
 Ingo Molnar <mingo@redhat.com>, Michael Kerrisk <mtk.manpages@gmail.com>,
 Palmer Dabbelt <palmerdabbelt@google.com>, Arnd Bergmann <arnd@arndb.de>,
 James Bottomley <jejb@linux.ibm.com>, Hagen Paul Pfeifer <hagen@jauu.net>,
 Borislav Petkov <bp@alien8.de>, Alexander Viro <viro@zeniv.linux.org.uk>,
 Andy Lutomirski <luto@kernel.org>, Paul Walmsley <paul.walmsley@sifive.com>,
 "Kirill A. Shutemov" <kirill@shutemov.name>,
 Dan Williams <dan.j.williams@intel.com>, linux-arm-kernel@lists.infradead.org,
 linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
 Palmer Dabbelt <palmer@dabbelt.com>, linux-fsdevel@vger.kernel.org,
 Shakeel Butt <shakeelb@google.com>, Andrew Morton <akpm@linux-foundation.org>,
 Rick Edgecombe <rick.p.edgecombe@intel.com>, Roman Gushchin <guro@fb.com>,
 Mike Rapoport <rppt@kernel.org>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "linux-riscv" <linux-riscv-bounces@lists.infradead.org>
Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org

On Thu 28-01-21 13:28:10, Cristopher Lameter wrote:
> On Thu, 28 Jan 2021, Michal Hocko wrote:
> 
> > > So, if I understand your concerns correct this implementation has two
> > > issues:
> > > 1) allocation failure at page fault that causes unrecoverable OOM and
> > > 2) a possibility for an unprivileged user to deplete secretmem pool and
> > > cause (1) to others
> > >
> > > I'm not really familiar with OOM internals, but when I simulated an
> > > allocation failure in my testing only the allocating process and it's
> > > parent were OOM-killed and then the system continued normally.
> >
> > If you kill the allocating process then yes, it would work, but your
> > process might be the very last to be selected.
> 
> OOMs are different if you have a "constrained allocation". In that case it
> is the fault of the process who wanted memory with certain conditions.
> That memory is not available. General memory is available though. In that
> case the allocating process is killed.

I do not see this implementation would do anything like that. Neither
anything like that implemented in the oom killer. Constrained
allocations (cpusets/memcg/mempolicy) only do restrict their selection
to processes which belong to the same domain. So I am not really sure
what you are referring to. The is only a global knob to _always_ kill
the allocating process on OOM.

-- 
Michal Hocko
SUSE Labs

_______________________________________________
linux-riscv mailing list
linux-riscv@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-riscv

From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <SRS0=ZyEH=G7=lists.infradead.org=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@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=-4.0 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH,
	DKIM_SIGNED,DKIM_VALID,HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,
	SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED 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 6F5CBC433E6
	for <linux-arm-kernel@archiver.kernel.org>; Thu, 28 Jan 2021 13:50:41 +0000 (UTC)
Received: from merlin.infradead.org (merlin.infradead.org [205.233.59.134])
	(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 1B0F66146D
	for <linux-arm-kernel@archiver.kernel.org>; Thu, 28 Jan 2021 13:50:41 +0000 (UTC)
DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1B0F66146D
Authentication-Results: mail.kernel.org; dmarc=fail (p=quarantine dis=none) header.from=suse.com
Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org
DKIM-Signature: v=1; a=rsa-sha256; q=dns/txt; c=relaxed/relaxed;
	d=lists.infradead.org; s=merlin.20170209; h=Sender:Content-Transfer-Encoding:
	Content-Type:Cc:List-Subscribe:List-Help:List-Post:List-Archive:
	List-Unsubscribe:List-Id:In-Reply-To:MIME-Version:References:Message-ID:
	Subject:To:From:Date:Reply-To:Content-ID:Content-Description:Resent-Date:
	Resent-From:Resent-Sender:Resent-To:Resent-Cc:Resent-Message-ID:List-Owner;
	 bh=5PQ3tOTqhfsHzB+tlT2eK7Dw6LCNwuqmmKdVxGivT/8=; b=lJmwXQGjq+gGaX70jr6w/l2yq
	OG41uiDY/lgAMPmdAgQwmoUsOE0JDjKkJSDujD7txXZjVDgygh7V0v6jnLvYf8COw4qjP9+/XeEtm
	uzgTRa+IGHDQ/REgpjOSW+LsWZ5i/5gn9DSHsaJQcByv/kaOVcXlxou62ZjATYM8vVQKhUz/d/i6d
	/HJ9PEJtUauOfoH0CA5bfAGHwcnfRBGvu3lGBRYn3Ba8FSU5x9XmeTas6qQ4PTWFvvOdmhNMFacy8
	0fjp0NHyFEtPdusBzp3vebSzq9DEJUD1ba2k12h7I9cNyL0tOyvW039TLDfAXU0vRowxzY2Z0GsOH
	qx9uvgsYQ==;
Received: from localhost ([::1] helo=merlin.infradead.org)
	by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux))
	id 1l57g3-0002y4-RK; Thu, 28 Jan 2021 13:49:39 +0000
Received: from mx2.suse.de ([195.135.220.15])
 by merlin.infradead.org with esmtps (Exim 4.92.3 #3 (Red Hat Linux))
 id 1l57g1-0002xE-0H; Thu, 28 Jan 2021 13:49:38 +0000
X-Virus-Scanned: by amavisd-new at test-mx.suse.de
DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=suse.com; s=susede1;
 t=1611841775; h=from:from:reply-to:date:date:message-id:message-id:to:to:cc:cc:
 mime-version:mime-version:content-type:content-type:
 in-reply-to:in-reply-to:references:references;
 bh=75llh3uw6L6UpTgmVsHlz+i8LHZJ84jNMGnauBZqITc=;
 b=RFEQmGK/LljkSM2oiWx77CIGoV0eKNOaEQIEAkrhzpN9jbb3MOKURRCYaRwYVt6/w/U/+e
 g4VVantqh8P7n2dKzYTMYQk4w9MXZKXSASL6hjd+n4xFytPepUsla6MMacf9DtnSP1AmZ/
 v2BcnFvMM+kSY0c0Ye3UOYH/R63VQ8Q=
Received: from relay2.suse.de (unknown [195.135.221.27])
 by mx2.suse.de (Postfix) with ESMTP id 9E752AF78;
 Thu, 28 Jan 2021 13:49:35 +0000 (UTC)
Date: Thu, 28 Jan 2021 14:49:34 +0100
From: Michal Hocko <mhocko@suse.com>
To: Christoph Lameter <cl@linux.com>
Subject: Re: [PATCH v16 07/11] secretmem: use PMD-size pages to amortize
 direct map fragmentation
Message-ID: <YBLA7sEKn01HXd/U@dhcp22.suse.cz>
References: <20210121122723.3446-1-rppt@kernel.org>
 <20210121122723.3446-8-rppt@kernel.org>
 <20210126114657.GL827@dhcp22.suse.cz>
 <303f348d-e494-e386-d1f5-14505b5da254@redhat.com>
 <20210126120823.GM827@dhcp22.suse.cz>
 <20210128092259.GB242749@kernel.org>
 <YBK1kqL7JA7NePBQ@dhcp22.suse.cz>
 <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
MIME-Version: 1.0
Content-Disposition: inline
In-Reply-To: <alpine.DEB.2.22.394.2101281326360.10563@www.lameter.com>
X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 
X-CRM114-CacheID: sfid-20210128_084937_387188_FCF55189 
X-CRM114-Status: GOOD (  21.60  )
X-BeenThere: linux-arm-kernel@lists.infradead.org
X-Mailman-Version: 2.1.29
Precedence: list
List-Id: <linux-arm-kernel.lists.infradead.org>
List-Unsubscribe: <http://lists.infradead.org/mailman/options/linux-arm-kernel>, 
 <mailto:linux-arm-kernel-request@lists.infradead.org?subject=unsubscribe>
List-Archive: <http://lists.infradead.org/pipermail/linux-arm-kernel/>
List-Post: <mailto:linux-arm-kernel@lists.infradead.org>
List-Help: <mailto:linux-arm-kernel-request@lists.infradead.org?subject=help>
List-Subscribe: <http://lists.infradead.org/mailman/listinfo/linux-arm-kernel>, 
 <mailto:linux-arm-kernel-request@lists.infradead.org?subject=subscribe>
Cc: Mark Rutland <mark.rutland@arm.com>, David Hildenbrand <david@redhat.com>,
 Peter Zijlstra <peterz@infradead.org>,
 Catalin Marinas <catalin.marinas@arm.com>,
 Dave Hansen <dave.hansen@linux.intel.com>, linux-mm@kvack.org,
 linux-kselftest@vger.kernel.org, "H. Peter Anvin" <hpa@zytor.com>,
 linux-riscv@lists.infradead.org, Shuah Khan <shuah@kernel.org>,
 Thomas Gleixner <tglx@linutronix.de>,
 Elena Reshetova <elena.reshetova@intel.com>, linux-arch@vger.kernel.org,
 Tycho Andersen <tycho@tycho.ws>, linux-nvdimm@lists.01.org,
 Will Deacon <will@kernel.org>, x86@kernel.org,
 Matthew Wilcox <willy@infradead.org>, Mike Rapoport <rppt@linux.ibm.com>,
 Ingo Molnar <mingo@redhat.com>, Michael Kerrisk <mtk.manpages@gmail.com>,
 Palmer Dabbelt <palmerdabbelt@google.com>, Arnd Bergmann <arnd@arndb.de>,
 James Bottomley <jejb@linux.ibm.com>, Hagen Paul Pfeifer <hagen@jauu.net>,
 Borislav Petkov <bp@alien8.de>, Alexander Viro <viro@zeniv.linux.org.uk>,
 Andy Lutomirski <luto@kernel.org>, Paul Walmsley <paul.walmsley@sifive.com>,
 "Kirill A. Shutemov" <kirill@shutemov.name>,
 Dan Williams <dan.j.williams@intel.com>, linux-arm-kernel@lists.infradead.org,
 linux-api@vger.kernel.org, linux-kernel@vger.kernel.org,
 Palmer Dabbelt <palmer@dabbelt.com>, linux-fsdevel@vger.kernel.org,
 Shakeel Butt <shakeelb@google.com>, Andrew Morton <akpm@linux-foundation.org>,
 Rick Edgecombe <rick.p.edgecombe@intel.com>, Roman Gushchin <guro@fb.com>,
 Mike Rapoport <rppt@kernel.org>
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Sender: "linux-arm-kernel" <linux-arm-kernel-bounces@lists.infradead.org>
Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org

On Thu 28-01-21 13:28:10, Cristopher Lameter wrote:
> On Thu, 28 Jan 2021, Michal Hocko wrote:
> 
> > > So, if I understand your concerns correct this implementation has two
> > > issues:
> > > 1) allocation failure at page fault that causes unrecoverable OOM and
> > > 2) a possibility for an unprivileged user to deplete secretmem pool and
> > > cause (1) to others
> > >
> > > I'm not really familiar with OOM internals, but when I simulated an
> > > allocation failure in my testing only the allocating process and it's
> > > parent were OOM-killed and then the system continued normally.
> >
> > If you kill the allocating process then yes, it would work, but your
> > process might be the very last to be selected.
> 
> OOMs are different if you have a "constrained allocation". In that case it
> is the fault of the process who wanted memory with certain conditions.
> That memory is not available. General memory is available though. In that
> case the allocating process is killed.

I do not see this implementation would do anything like that. Neither
anything like that implemented in the oom killer. Constrained
allocations (cpusets/memcg/mempolicy) only do restrict their selection
to processes which belong to the same domain. So I am not really sure
what you are referring to. The is only a global knob to _always_ kill
the allocating process on OOM.

-- 
Michal Hocko
SUSE Labs

_______________________________________________
linux-arm-kernel mailing list
linux-arm-kernel@lists.infradead.org
http://lists.infradead.org/mailman/listinfo/linux-arm-kernel