From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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=-3.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,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 60298C433E6 for ; Tue, 9 Feb 2021 20:08:38 +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 0879E64E8C for ; Tue, 9 Feb 2021 20:08:37 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0879E64E8C 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 7317E100EAB7E; Tue, 9 Feb 2021 12:08:37 -0800 (PST) Received-SPF: Pass (mailfrom) identity=mailfrom; client-ip=195.135.220.15; helo=mx2.suse.de; envelope-from=mhocko@suse.com; receiver= 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 C532E100EAB78 for ; Tue, 9 Feb 2021 12:08:34 -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=1612901312; 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=utBmzEHnMldk+xybu3FUHQ/4GijdaViYwt5S9/fMX5g=; b=TjFv3w1m/0Glle7o/mpLcPWsTy958OLjFP0MF4y2grgkrogeIq5dCnnfB5BszcW5ggUnqY LL4MV1a1lL2B5WOEu6FaOYZ3DET/TzX9b1n3q4/VP0Y/08QiHTyolRop/Pd6AqhLXBScSy PBnAIDa+ir2IADhVPtKtqxwjkXo403U= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AC40AADF0; Tue, 9 Feb 2021 20:08:32 +0000 (UTC) Date: Tue, 9 Feb 2021 21:08:31 +0100 From: Michal Hocko To: David Hildenbrand Subject: Re: [PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: References: <20210208211326.GV242749@kernel.org> <1F6A73CF-158A-4261-AA6C-1F5C77F4F326@redhat.com> <662b5871-b461-0896-697f-5e903c23d7b9@redhat.com> <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> Message-ID-Hash: NWWHFL3B5T7V5SJ3N7KOK5X5DCQCVYQZ X-Message-ID-Hash: NWWHFL3B5T7V5SJ3N7KOK5X5DCQCVYQZ 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 , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dave Hansen , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Ander sen , Will Deacon , 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." Archived-At: List-Archive: List-Help: List-Post: List-Subscribe: List-Unsubscribe: Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Tue 09-02-21 17:17:22, David Hildenbrand wrote: > On 09.02.21 14:25, Michal Hocko wrote: > > On Tue 09-02-21 11:23:35, David Hildenbrand wrote: > > [...] > > > I am constantly trying to fight for making more stuff MOVABLE instead of > > > going into the other direction (e.g., because it's easier to implement, > > > which feels like the wrong direction). > > > > > > Maybe I am the only person that really cares about ZONE_MOVABLE these days > > > :) I can't stop such new stuff from popping up, so at least I want it to be > > > documented. > > > > MOVABLE zone is certainly an important thing to keep working. And there > > is still quite a lot of work on the way. But as I've said this is more > > of a outlier than a norm. On the other hand movable zone is kinda hard > > requirement for a lot of application and it is to be expected that > > many features will be less than 100% compatible. Some usecases even > > impossible. That's why I am arguing that we should have a central > > document where the movable zone is documented with all the potential > > problems we have encountered over time and explicitly state which > > features are fully/partially incompatible. > > > > I'll send a mail during the next weeks to gather current restrictions to > document them (and include my brain dump). We might see more excessive use > of ZONE_MOVABLE in the future and as history told us, of CMA as well. We > really should start documenting/caring. Excellent! Thanks a lot. I will do my best to help reviewing that. > @Mike, it would be sufficient for me if one of your patches at least mention > the situation in the description like > > "Please note that secretmem currently behaves much more like long-term GUP > instead of mlocked memory; secretmem is unmovable memory directly > consumed/controlled by user space. secretmem cannot be placed onto > ZONE_MOVABLE/CMA. Sounds good to me. -- 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: 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 466C5C433DB for ; Wed, 10 Feb 2021 00:15:29 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0156E64E74 for ; Wed, 10 Feb 2021 00:15:28 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234439AbhBJAPU (ORCPT ); Tue, 9 Feb 2021 19:15:20 -0500 Received: from mx2.suse.de ([195.135.220.15]:47834 "EHLO mx2.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233733AbhBIUqB (ORCPT ); Tue, 9 Feb 2021 15:46:01 -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=1612901312; 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=utBmzEHnMldk+xybu3FUHQ/4GijdaViYwt5S9/fMX5g=; b=TjFv3w1m/0Glle7o/mpLcPWsTy958OLjFP0MF4y2grgkrogeIq5dCnnfB5BszcW5ggUnqY LL4MV1a1lL2B5WOEu6FaOYZ3DET/TzX9b1n3q4/VP0Y/08QiHTyolRop/Pd6AqhLXBScSy PBnAIDa+ir2IADhVPtKtqxwjkXo403U= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AC40AADF0; Tue, 9 Feb 2021 20:08:32 +0000 (UTC) Date: Tue, 9 Feb 2021 21:08:31 +0100 From: Michal Hocko To: David Hildenbrand Cc: Mike Rapoport , Andrew Morton , Alexander Viro , Andy Lutomirski , Arnd Bergmann , Borislav Petkov , Catalin Marinas , Christopher Lameter , Dan Williams , Dave Hansen , Elena Reshetova , "H. Peter Anvin" , Ingo Molnar , James Bottomley , "Kirill A. Shutemov" , Matthew Wilcox , Mark Rutland , Mike Rapoport , Michael Kerrisk , Palmer Dabbelt , Paul Walmsley , Peter Zijlstra , Rick Edgecombe , Roman Gushchin , Shakeel Butt , Shuah Khan , Thomas Gleixner , Tycho Andersen , Will Deacon , 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 Subject: Re: [PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: References: <20210208211326.GV242749@kernel.org> <1F6A73CF-158A-4261-AA6C-1F5C77F4F326@redhat.com> <662b5871-b461-0896-697f-5e903c23d7b9@redhat.com> <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue 09-02-21 17:17:22, David Hildenbrand wrote: > On 09.02.21 14:25, Michal Hocko wrote: > > On Tue 09-02-21 11:23:35, David Hildenbrand wrote: > > [...] > > > I am constantly trying to fight for making more stuff MOVABLE instead of > > > going into the other direction (e.g., because it's easier to implement, > > > which feels like the wrong direction). > > > > > > Maybe I am the only person that really cares about ZONE_MOVABLE these days > > > :) I can't stop such new stuff from popping up, so at least I want it to be > > > documented. > > > > MOVABLE zone is certainly an important thing to keep working. And there > > is still quite a lot of work on the way. But as I've said this is more > > of a outlier than a norm. On the other hand movable zone is kinda hard > > requirement for a lot of application and it is to be expected that > > many features will be less than 100% compatible. Some usecases even > > impossible. That's why I am arguing that we should have a central > > document where the movable zone is documented with all the potential > > problems we have encountered over time and explicitly state which > > features are fully/partially incompatible. > > > > I'll send a mail during the next weeks to gather current restrictions to > document them (and include my brain dump). We might see more excessive use > of ZONE_MOVABLE in the future and as history told us, of CMA as well. We > really should start documenting/caring. Excellent! Thanks a lot. I will do my best to help reviewing that. > @Mike, it would be sufficient for me if one of your patches at least mention > the situation in the description like > > "Please note that secretmem currently behaves much more like long-term GUP > instead of mlocked memory; secretmem is unmovable memory directly > consumed/controlled by user space. secretmem cannot be placed onto > ZONE_MOVABLE/CMA. Sounds good to me. -- Michal Hocko SUSE Labs From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: 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=-4.3 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 1C5B2C433E0 for ; Tue, 9 Feb 2021 20:08:55 +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 94F6A64E9C for ; Tue, 9 Feb 2021 20:08:54 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 94F6A64E9C 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=hvOn7Gco4Uy9K3mXvrhO0PY54RoEk+c/2Y6w7SJ1Re0=; b=IcH/HSWGd4IzuT8HRY0XpTHgG q98y7BBkeWSR3wD7fY7pBXYvdDgvt8AVUvYnYSlO+BYHTNMBCYcuWin5m4AnnrrNCcbSL2yKn3d9Q +qQsVlJC5PgKzXqk7GhfUXwd4iY0LUI494ZVyAbGxj4GdJu3UKEUlYQsjK318ISWUGD+TJBknDnk2 QSFFMaHegtBSKT3ZOaGcDh7SzyNJgu0IOng+VumxGnyvCbkNLdX16QiUusJXlT+M1crDzAUZUuXYp cunaSZtfRqQeRGTON98Z+nDy1ibR24ORvq86rX6mjTna7kt4omLDbUxtwvDZJKiYHphv1ozhjG7LN Pr6s9kVTQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9ZJP-0002Tz-RQ; Tue, 09 Feb 2021 20:08:39 +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 1l9ZJL-0002SQ-6H; Tue, 09 Feb 2021 20:08:36 +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=1612901312; 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=utBmzEHnMldk+xybu3FUHQ/4GijdaViYwt5S9/fMX5g=; b=TjFv3w1m/0Glle7o/mpLcPWsTy958OLjFP0MF4y2grgkrogeIq5dCnnfB5BszcW5ggUnqY LL4MV1a1lL2B5WOEu6FaOYZ3DET/TzX9b1n3q4/VP0Y/08QiHTyolRop/Pd6AqhLXBScSy PBnAIDa+ir2IADhVPtKtqxwjkXo403U= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AC40AADF0; Tue, 9 Feb 2021 20:08:32 +0000 (UTC) Date: Tue, 9 Feb 2021 21:08:31 +0100 From: Michal Hocko To: David Hildenbrand Subject: Re: [PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: References: <20210208211326.GV242749@kernel.org> <1F6A73CF-158A-4261-AA6C-1F5C77F4F326@redhat.com> <662b5871-b461-0896-697f-5e903c23d7b9@redhat.com> <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210209_150835_538961_DC44755F X-CRM114-Status: GOOD ( 22.92 ) X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Arnd Bergmann , James Bottomley , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin , Mike Rapoport Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-riscv" Errors-To: linux-riscv-bounces+linux-riscv=archiver.kernel.org@lists.infradead.org On Tue 09-02-21 17:17:22, David Hildenbrand wrote: > On 09.02.21 14:25, Michal Hocko wrote: > > On Tue 09-02-21 11:23:35, David Hildenbrand wrote: > > [...] > > > I am constantly trying to fight for making more stuff MOVABLE instead of > > > going into the other direction (e.g., because it's easier to implement, > > > which feels like the wrong direction). > > > > > > Maybe I am the only person that really cares about ZONE_MOVABLE these days > > > :) I can't stop such new stuff from popping up, so at least I want it to be > > > documented. > > > > MOVABLE zone is certainly an important thing to keep working. And there > > is still quite a lot of work on the way. But as I've said this is more > > of a outlier than a norm. On the other hand movable zone is kinda hard > > requirement for a lot of application and it is to be expected that > > many features will be less than 100% compatible. Some usecases even > > impossible. That's why I am arguing that we should have a central > > document where the movable zone is documented with all the potential > > problems we have encountered over time and explicitly state which > > features are fully/partially incompatible. > > > > I'll send a mail during the next weeks to gather current restrictions to > document them (and include my brain dump). We might see more excessive use > of ZONE_MOVABLE in the future and as history told us, of CMA as well. We > really should start documenting/caring. Excellent! Thanks a lot. I will do my best to help reviewing that. > @Mike, it would be sufficient for me if one of your patches at least mention > the situation in the description like > > "Please note that secretmem currently behaves much more like long-term GUP > instead of mlocked memory; secretmem is unmovable memory directly > consumed/controlled by user space. secretmem cannot be placed onto > ZONE_MOVABLE/CMA. Sounds good to me. -- 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: 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=-4.3 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 B313FC433E0 for ; Tue, 9 Feb 2021 20:09:56 +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 4F9E364EAA for ; Tue, 9 Feb 2021 20:09:56 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 4F9E364EAA 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=Bv7ffNPHyBUOI4DQJEmpLEYehtbPK7BVKdUMnB1ujCo=; b=qEz5ph4KsJgi3w7FaI2i9OY4Y 8don2KCFl0n7h/B5rjnIpyJicpADAioDLNZCzG1oLTbkTM8xKJwDOtWiZ1WWMZe/bFAZfB6vvPyL3 Kn7RgqEbN7ZsuJ7G6TklPMq2iRj9Ju6oXyEmDEnJFywfaJoCdcdRE1OhiW8K/UUI9EVWWkpo7OUG+ 3l7chzp54j1NVIXJ8J5/IRQZ35KH/bejWt1aWWkexL5Zp58Dmuo90DjrMUdtE9FbvOzhdgPgJnUMV XgWJ26v0A5WwyOynWQ2B01HNGPcH1oYEWVXSDHal5f229QnP8ELvoKHNlof5WysIqaSpaf+Lzbsiu UqjO9gSjQ==; Received: from localhost ([::1] helo=merlin.infradead.org) by merlin.infradead.org with esmtp (Exim 4.92.3 #3 (Red Hat Linux)) id 1l9ZJO-0002Tl-J6; Tue, 09 Feb 2021 20:08:38 +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 1l9ZJL-0002SQ-6H; Tue, 09 Feb 2021 20:08:36 +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=1612901312; 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=utBmzEHnMldk+xybu3FUHQ/4GijdaViYwt5S9/fMX5g=; b=TjFv3w1m/0Glle7o/mpLcPWsTy958OLjFP0MF4y2grgkrogeIq5dCnnfB5BszcW5ggUnqY LL4MV1a1lL2B5WOEu6FaOYZ3DET/TzX9b1n3q4/VP0Y/08QiHTyolRop/Pd6AqhLXBScSy PBnAIDa+ir2IADhVPtKtqxwjkXo403U= Received: from relay2.suse.de (unknown [195.135.221.27]) by mx2.suse.de (Postfix) with ESMTP id AC40AADF0; Tue, 9 Feb 2021 20:08:32 +0000 (UTC) Date: Tue, 9 Feb 2021 21:08:31 +0100 From: Michal Hocko To: David Hildenbrand Subject: Re: [PATCH v17 00/10] mm: introduce memfd_secret system call to create "secret" memory areas Message-ID: References: <20210208211326.GV242749@kernel.org> <1F6A73CF-158A-4261-AA6C-1F5C77F4F326@redhat.com> <662b5871-b461-0896-697f-5e903c23d7b9@redhat.com> <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> MIME-Version: 1.0 Content-Disposition: inline In-Reply-To: <8cbfe2c3-cfc6-72e0-bab1-852f80e20684@redhat.com> X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20210209_150835_538961_DC44755F X-CRM114-Status: GOOD ( 22.92 ) X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Mark Rutland , Peter Zijlstra , Catalin Marinas , Dave Hansen , linux-mm@kvack.org, linux-kselftest@vger.kernel.org, "H. Peter Anvin" , Christopher Lameter , Shuah Khan , Thomas Gleixner , Elena Reshetova , linux-arch@vger.kernel.org, Tycho Andersen , linux-nvdimm@lists.01.org, Will Deacon , x86@kernel.org, Matthew Wilcox , Mike Rapoport , Ingo Molnar , Michael Kerrisk , Arnd Bergmann , James Bottomley , Borislav Petkov , Alexander Viro , Andy Lutomirski , Paul Walmsley , "Kirill A. Shutemov" , Dan Williams , linux-arm-kernel@lists.infradead.org, linux-api@vger.kernel.org, linux-kernel@vger.kernel.org, linux-riscv@lists.infradead.org, Palmer Dabbelt , linux-fsdevel@vger.kernel.org, Shakeel Butt , Andrew Morton , Rick Edgecombe , Roman Gushchin , Mike Rapoport Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: "linux-arm-kernel" Errors-To: linux-arm-kernel-bounces+linux-arm-kernel=archiver.kernel.org@lists.infradead.org On Tue 09-02-21 17:17:22, David Hildenbrand wrote: > On 09.02.21 14:25, Michal Hocko wrote: > > On Tue 09-02-21 11:23:35, David Hildenbrand wrote: > > [...] > > > I am constantly trying to fight for making more stuff MOVABLE instead of > > > going into the other direction (e.g., because it's easier to implement, > > > which feels like the wrong direction). > > > > > > Maybe I am the only person that really cares about ZONE_MOVABLE these days > > > :) I can't stop such new stuff from popping up, so at least I want it to be > > > documented. > > > > MOVABLE zone is certainly an important thing to keep working. And there > > is still quite a lot of work on the way. But as I've said this is more > > of a outlier than a norm. On the other hand movable zone is kinda hard > > requirement for a lot of application and it is to be expected that > > many features will be less than 100% compatible. Some usecases even > > impossible. That's why I am arguing that we should have a central > > document where the movable zone is documented with all the potential > > problems we have encountered over time and explicitly state which > > features are fully/partially incompatible. > > > > I'll send a mail during the next weeks to gather current restrictions to > document them (and include my brain dump). We might see more excessive use > of ZONE_MOVABLE in the future and as history told us, of CMA as well. We > really should start documenting/caring. Excellent! Thanks a lot. I will do my best to help reviewing that. > @Mike, it would be sufficient for me if one of your patches at least mention > the situation in the description like > > "Please note that secretmem currently behaves much more like long-term GUP > instead of mlocked memory; secretmem is unmovable memory directly > consumed/controlled by user space. secretmem cannot be placed onto > ZONE_MOVABLE/CMA. Sounds good to me. -- Michal Hocko SUSE Labs _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel