From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sean Christopherson Date: Tue, 5 Sep 2023 16:56:31 -0700 Subject: [PATCH gmem FIXUP] mm, compaction: make testing mapping_unmovable() safe In-Reply-To: <20230901082025.20548-2-vbabka@suse.cz> References: <20230901082025.20548-2-vbabka@suse.cz> Message-ID: List-Id: To: kvm-riscv@lists.infradead.org MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit On Fri, Sep 01, 2023, Vlastimil Babka wrote: > As Kirill pointed out, mapping can be removed under us due to > truncation. Test it under folio lock as already done for the async > compaction / dirty folio case. To prevent locking every folio with > mapping to do the test, do it only for unevictable folios, as we can > expect the unmovable mapping folios are also unevictable - it is the > case for guest memfd folios. Rather than expect/assume that unmovable mappings are always unevictable, how about requiring that? E.g. either through a VM_WARN_ON in mapping_set_unmovable(), or by simply having that helper forcefully set AS_UNEVICTABLE as well. From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from mail-yb1-f202.google.com (mail-yb1-f202.google.com [209.85.219.202]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id E0775FC1E for ; Tue, 5 Sep 2023 23:56:33 +0000 (UTC) Received: by mail-yb1-f202.google.com with SMTP id 3f1490d57ef6-d782a2ba9f9so747290276.0 for ; Tue, 05 Sep 2023 16:56:33 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=google.com; s=20221208; t=1693958193; x=1694562993; darn=lists.linux.dev; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:from:to:cc:subject:date:message-id:reply-to; bh=BTMdUX0G2lv2+kU2WiYySTJObpffzgV002stI1a1W7I=; b=P6nTDGsqrvOlsUpkJ+uU9k6KmMSLVztzZ4rQWUWSQ/ReoSNncuaqG3bj9H4LZt/jnq KvZ1ShcQbsklC366kKYBG3UtJSAxvfPYVIi0yEK4cr+jtU++2QVEu345Hi192abzillv h2QD5sqhdoSt7S9/rt9ME3lgmbCnOWfE5/SaU4izL28WX9+FXlUIkgHq8PYDWYSEewtw Gjl7pzhBBlPCEMWjizVuWv5RypJ2IGtIRJdn6TTYdsACHcaymBEfKiSMSZ0ri9BskeeC lYTcHh8gnO25obqMNKkuve18LdjwvE/8HOnQxa9qE1LkkZ2oICBEfaQkjmF4DcMfT1hg Bcvg== X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693958193; x=1694562993; h=cc:to:from:subject:message-id:references:mime-version:in-reply-to :date:x-gm-message-state:from:to:cc:subject:date:message-id:reply-to; bh=BTMdUX0G2lv2+kU2WiYySTJObpffzgV002stI1a1W7I=; b=PqdxaPq2ozaaTJxilpXNzxSuG5KHf2p8OE5AZSh4OxjnCJhqXkFOm7z464Mbb6fpYX CXNLwlsss01bXFh1wOP8bhPX9+16/lBEGc+0vo+ETopHRNTFj0r/hobzyHbBNkYzj/RN tqGSZDEOKMrppdKj+QN2E4wEbQDmOCOsehzsMDSvD2vOZaPHSrew81OOTHA4c5+AkDsK 1iIRcL+U2kmtxuRd8ak/EPHqK/MWrpQJYDenLAKvY19PaTFFeuCzoiRaC0OnGGuepyQN DJKnigwONlunxiRZdyftcpUy/GjoY4cVkvsYEAILqHQpsILAGVHvYMdEe1yvftdGJnki o6WA== X-Gm-Message-State: AOJu0YzPFa8EDahODZ6byJJdyxFr4qfXQhkHZGhvWBrX1NrAIs7MFx/L 5DLFv5lKbKTp57BMDi802r7VcoogaGc= X-Google-Smtp-Source: AGHT+IGHRLIyxOEOlqNogao+wtJt3d7D+zZNTRSCijTepfZz1QuZZsrU81NGe3dzgdfi+rQuqyfdUQCuPic= X-Received: from zagreus.c.googlers.com ([fda3:e722:ac3:cc00:7f:e700:c0a8:5c37]) (user=seanjc job=sendgmr) by 2002:a25:4211:0:b0:d7e:c4af:22d2 with SMTP id p17-20020a254211000000b00d7ec4af22d2mr293199yba.4.1693958192804; Tue, 05 Sep 2023 16:56:32 -0700 (PDT) Date: Tue, 5 Sep 2023 16:56:31 -0700 In-Reply-To: <20230901082025.20548-2-vbabka@suse.cz> Precedence: bulk X-Mailing-List: kvmarm@lists.linux.dev List-Id: List-Subscribe: List-Unsubscribe: Mime-Version: 1.0 References: <20230901082025.20548-2-vbabka@suse.cz> Message-ID: Subject: Re: [PATCH gmem FIXUP] mm, compaction: make testing mapping_unmovable() safe From: Sean Christopherson To: Vlastimil Babka Cc: ackerleytng@google.com, akpm@linux-foundation.org, anup@brainfault.org, aou@eecs.berkeley.edu, chao.p.peng@linux.intel.com, chenhuacai@kernel.org, david@redhat.com, isaku.yamahata@gmail.com, jarkko@kernel.org, jmorris@namei.org, kirill.shutemov@linux.intel.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.linux.dev, liam.merwick@oracle.com, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-security-module@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mail@maciej.szmigiero.name, maz@kernel.org, michael.roth@amd.com, mpe@ellerman.id.au, oliver.upton@linux.dev, palmer@dabbelt.com, paul.walmsley@sifive.com, paul@paul-moore.com, pbonzini@redhat.com, qperret@google.com, serge@hallyn.com, tabba@google.com, vannapurve@google.com, wei.w.wang@intel.com, willy@infradead.org, yu.c.zhang@linux.intel.com Content-Type: text/plain; charset="us-ascii" On Fri, Sep 01, 2023, Vlastimil Babka wrote: > As Kirill pointed out, mapping can be removed under us due to > truncation. Test it under folio lock as already done for the async > compaction / dirty folio case. To prevent locking every folio with > mapping to do the test, do it only for unevictable folios, as we can > expect the unmovable mapping folios are also unevictable - it is the > case for guest memfd folios. Rather than expect/assume that unmovable mappings are always unevictable, how about requiring that? E.g. either through a VM_WARN_ON in mapping_set_unmovable(), or by simply having that helper forcefully set AS_UNEVICTABLE as well. 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Tue, 05 Sep 2023 16:56:32 -0700 (PDT) Date: Tue, 5 Sep 2023 16:56:31 -0700 In-Reply-To: <20230901082025.20548-2-vbabka@suse.cz> Mime-Version: 1.0 References: <20230901082025.20548-2-vbabka@suse.cz> Message-ID: Subject: Re: [PATCH gmem FIXUP] mm, compaction: make testing mapping_unmovable() safe From: Sean Christopherson To: Vlastimil Babka Cc: ackerleytng@google.com, akpm@linux-foundation.org, anup@brainfault.org, aou@eecs.berkeley.edu, chao.p.peng@linux.intel.com, chenhuacai@kernel.org, david@redhat.com, isaku.yamahata@gmail.com, jarkko@kernel.org, jmorris@namei.org, kirill.shutemov@linux.intel.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.linux.dev, liam.merwick@oracle.com, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-security-module@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mail@maciej.szmigiero.name, maz@kernel.org, michael.roth@amd.com, mpe@ellerman.id.au, oliver.upton@linux.dev, palmer@dabbelt.com, paul.walmsley@sifive.com, paul@paul-moore.com, pbonzini@redhat.com, qperret@google.com, serge@hallyn.com, tabba@google.com, vannapurve@google.com, wei.w.wang@intel.com, willy@infradead.org, yu.c.zhang@linux.intel.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230905_165635_268348_67C72983 X-CRM114-Status: UNSURE ( 8.35 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-riscv@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Fri, Sep 01, 2023, Vlastimil Babka wrote: > As Kirill pointed out, mapping can be removed under us due to > truncation. Test it under folio lock as already done for the async > compaction / dirty folio case. To prevent locking every folio with > mapping to do the test, do it only for unevictable folios, as we can > expect the unmovable mapping folios are also unevictable - it is the > case for guest memfd folios. Rather than expect/assume that unmovable mappings are always unevictable, how about requiring that? E.g. either through a VM_WARN_ON in mapping_set_unmovable(), or by simply having that helper forcefully set AS_UNEVICTABLE as well. _______________________________________________ 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 Received: from lists.ozlabs.org (lists.ozlabs.org [112.213.38.117]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id 7F6FFCCF9E9 for ; Tue, 5 Sep 2023 23:57:31 +0000 (UTC) Authentication-Results: lists.ozlabs.org; dkim=fail reason="signature verification failed" (2048-bit key; unprotected) header.d=google.com header.i=@google.com header.a=rsa-sha256 header.s=20221208 header.b=kjEvzwHI; dkim-atps=neutral Received: from boromir.ozlabs.org (localhost [IPv6:::1]) by lists.ozlabs.org (Postfix) with ESMTP id 4RgMr96j9jz3bxS for ; 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Tue, 05 Sep 2023 16:56:32 -0700 (PDT) Date: Tue, 5 Sep 2023 16:56:31 -0700 In-Reply-To: <20230901082025.20548-2-vbabka@suse.cz> Mime-Version: 1.0 References: <20230901082025.20548-2-vbabka@suse.cz> Message-ID: Subject: Re: [PATCH gmem FIXUP] mm, compaction: make testing mapping_unmovable() safe From: Sean Christopherson To: Vlastimil Babka Content-Type: text/plain; charset="us-ascii" X-BeenThere: linuxppc-dev@lists.ozlabs.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: Linux on PowerPC Developers Mail List List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: kvm@vger.kernel.org, david@redhat.com, yu.c.zhang@linux.intel.com, linux-mips@vger.kernel.org, linux-mm@kvack.org, pbonzini@redhat.com, chao.p.peng@linux.intel.com, linux-riscv@lists.infradead.org, isaku.yamahata@gmail.com, paul@paul-moore.com, anup@brainfault.org, chenhuacai@kernel.org, jmorris@namei.org, willy@infradead.org, wei.w.wang@intel.com, tabba@google.com, jarkko@kernel.org, serge@hallyn.com, mail@maciej.szmigiero.name, aou@eecs.berkeley.edu, michael.roth@amd.com, ackerleytng@google.com, paul.walmsley@sifive.com, kvmarm@lists.linux.dev, linux-arm-kernel@lists.infradead.org, qperret@google.com, linux-kernel@vger.kernel.org, oliver.upton@linux.dev, linux-security-module@vger.kernel.org, palmer@dabbelt.com, kvm-riscv@lists.infradead.org, maz@kernel.org, linux-fsdevel@vger.kernel.org, liam.merwick@oracle.com, akpm@linux-foundation.org, vannapurve@google.com, linuxppc-dev@lists.ozlabs.org, kirill.shutemov@linux.intel.com Errors-To: linuxppc-dev-bounces+linuxppc-dev=archiver.kernel.org@lists.ozlabs.org Sender: "Linuxppc-dev" On Fri, Sep 01, 2023, Vlastimil Babka wrote: > As Kirill pointed out, mapping can be removed under us due to > truncation. Test it under folio lock as already done for the async > compaction / dirty folio case. To prevent locking every folio with > mapping to do the test, do it only for unevictable folios, as we can > expect the unmovable mapping folios are also unevictable - it is the > case for guest memfd folios. Rather than expect/assume that unmovable mappings are always unevictable, how about requiring that? E.g. either through a VM_WARN_ON in mapping_set_unmovable(), or by simply having that helper forcefully set AS_UNEVICTABLE as well. 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Tue, 05 Sep 2023 16:56:32 -0700 (PDT) Date: Tue, 5 Sep 2023 16:56:31 -0700 In-Reply-To: <20230901082025.20548-2-vbabka@suse.cz> Mime-Version: 1.0 References: <20230901082025.20548-2-vbabka@suse.cz> Message-ID: Subject: Re: [PATCH gmem FIXUP] mm, compaction: make testing mapping_unmovable() safe From: Sean Christopherson To: Vlastimil Babka Cc: ackerleytng@google.com, akpm@linux-foundation.org, anup@brainfault.org, aou@eecs.berkeley.edu, chao.p.peng@linux.intel.com, chenhuacai@kernel.org, david@redhat.com, isaku.yamahata@gmail.com, jarkko@kernel.org, jmorris@namei.org, kirill.shutemov@linux.intel.com, kvm-riscv@lists.infradead.org, kvm@vger.kernel.org, kvmarm@lists.linux.dev, liam.merwick@oracle.com, linux-arm-kernel@lists.infradead.org, linux-fsdevel@vger.kernel.org, linux-kernel@vger.kernel.org, linux-mips@vger.kernel.org, linux-mm@kvack.org, linux-riscv@lists.infradead.org, linux-security-module@vger.kernel.org, linuxppc-dev@lists.ozlabs.org, mail@maciej.szmigiero.name, maz@kernel.org, michael.roth@amd.com, mpe@ellerman.id.au, oliver.upton@linux.dev, palmer@dabbelt.com, paul.walmsley@sifive.com, paul@paul-moore.com, pbonzini@redhat.com, qperret@google.com, serge@hallyn.com, tabba@google.com, vannapurve@google.com, wei.w.wang@intel.com, willy@infradead.org, yu.c.zhang@linux.intel.com X-CRM114-Version: 20100106-BlameMichelson ( TRE 0.8.0 (BSD) ) MR-646709E3 X-CRM114-CacheID: sfid-20230905_165635_469591_72284465 X-CRM114-Status: UNSURE ( 9.98 ) X-CRM114-Notice: Please train this message. X-BeenThere: linux-arm-kernel@lists.infradead.org X-Mailman-Version: 2.1.34 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , 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 Fri, Sep 01, 2023, Vlastimil Babka wrote: > As Kirill pointed out, mapping can be removed under us due to > truncation. Test it under folio lock as already done for the async > compaction / dirty folio case. To prevent locking every folio with > mapping to do the test, do it only for unevictable folios, as we can > expect the unmovable mapping folios are also unevictable - it is the > case for guest memfd folios. Rather than expect/assume that unmovable mappings are always unevictable, how about requiring that? E.g. either through a VM_WARN_ON in mapping_set_unmovable(), or by simply having that helper forcefully set AS_UNEVICTABLE as well. _______________________________________________ linux-arm-kernel mailing list linux-arm-kernel@lists.infradead.org http://lists.infradead.org/mailman/listinfo/linux-arm-kernel