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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1D29FCCF9E9 for ; Tue, 5 Sep 2023 23:56:42 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241887AbjIEX4j (ORCPT ); Tue, 5 Sep 2023 19:56:39 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40974 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S229639AbjIEX4h (ORCPT ); Tue, 5 Sep 2023 19:56:37 -0400 Received: from mail-yb1-xb49.google.com (mail-yb1-xb49.google.com [IPv6:2607:f8b0:4864:20::b49]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 86CBE1AB for ; Tue, 5 Sep 2023 16:56:33 -0700 (PDT) Received: by mail-yb1-xb49.google.com with SMTP id 3f1490d57ef6-d7c676651c7so713689276.1 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=vger.kernel.org; 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=e7n6Yjksn2CMZRtFHL5RDakHGb5NbF8DYWqlKCV2VtvDz+bekmAxT60g6N1QEt4Q9x TnsqFvLITcWcza8/3XwZpqAt0gi0gYzd1nGQYtSJxMLnJNH2oHGZIMTvMrQVoz/ZFZik tbKvfANIdod5uVbLAZYsDMDpiT3PiNLOr8kAox4fLx9MwiOZYQKmhuLC6uF8FytOaf5d qY3XUntd/mCB+S4TE8YGHPYj5zzee1tN1PA42iKcQUw5WQLVQW/JKAEVFoQlof+IXjgO Fcy86VDmQgAqbHsdDgcGCn8ZxzB3Jb49XYlt7LU9Mv15oAV8iTZFBLCCmUqI4wpgNEW6 QFFw== 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=arPqTjH+m3hRuGIMFGnyGOvfZs1yS6vVPbiUpoN5mhbP3+rIUTXhhJm1fOjoyqhBN6 C5cYpmJLjaFfSmdyMSbehW/3FHeuK+y33tCeG70NIt6TXj6vRX9Wp+uZgmhhbBin7MM3 Ip9m8bMY8re6TM4zXZtHZ0+pDwCQm53blqPEfZVdXCQV54cRoiwF5TRqxbrNCA3th3Xx +z4r0BukkhyKngpQyN2VrVgrANO2z0/MqaCtnXX2QYVleYyww/JaU21xq8v26TdSOTpu oRqIaDov86LGKoOwRmARJEtg5j3hKOE2sFaMDqxfZb3C2lpxj2F9rBfLuDAeMRXKPKD2 KUJw== X-Gm-Message-State: AOJu0YyowxV/vwdq3b3HkSB9+BVi4l2vnK+sdZzQxxx726tAQtcIlHj2 ZEoBu6axQuDtqAGXtZZWbALdnPK6BbY= 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> 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" Precedence: bulk List-ID: X-Mailing-List: linux-fsdevel@vger.kernel.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.