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 kanga.kvack.org (kanga.kvack.org [205.233.56.17]) (using TLSv1 with cipher DHE-RSA-AES256-SHA (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id E4CDEC79FB9 for ; Thu, 10 Sep 2026 10:03:48 +0000 (UTC) Received: by kanga.kvack.org (Postfix) id C5B7B6B008A; Thu, 10 Sep 2026 06:03:47 -0400 (EDT) Received: by kanga.kvack.org (Postfix, from userid 40) id C0C4C6B0092; Thu, 10 Sep 2026 06:03:47 -0400 (EDT) X-Delivered-To: int-list-linux-mm@kvack.org Received: by kanga.kvack.org (Postfix, from userid 63042) id ADB286B0095; Thu, 10 Sep 2026 06:03:47 -0400 (EDT) X-Delivered-To: linux-mm@kvack.org Received: from relay.hostedemail.com (smtprelay0017.hostedemail.com [216.40.44.17]) by kanga.kvack.org (Postfix) with ESMTP id 9170D6B008A for ; Thu, 10 Sep 2026 06:03:47 -0400 (EDT) Received: from smtpin19.hostedemail.com (lb01a-stub [10.200.18.249]) by unirelay01.hostedemail.com (Postfix) with ESMTP id 637B01C2315 for ; Thu, 10 Sep 2026 10:03:45 +0000 (UTC) X-FDA: 85197416010.19.A17315A Received: from tor.source.kernel.org (tor.source.kernel.org [172.105.4.254]) by imf13.hostedemail.com (Postfix) with ESMTP id 80DD120006 for ; Thu, 10 Sep 2026 10:03:43 +0000 (UTC) Authentication-Results: imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=KSilTxny; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf13.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org ARC-Message-Signature: i=1; a=rsa-sha256; c=relaxed/relaxed; d=hostedemail.com; s=arc-20220608; t=1789034623; h=from:from:sender: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:dkim-signature; bh=d6X874Xrr4USoK1MTGkxBCcI6O6k/kEejm0Rs8M2xgI=; b=JOos8r68f/6iELdsEPZ7UiG6eaJmhsWaa8H8WsKCz1akkiyAdPU2THjZB17KYZkU+amkis YGdUyC4EGA8X/Fz7OTcL8gUSWko6gQunP8UEhp1ssvjJXYf4yUK2O8sC10OE7ppvp0IIos VySjlq+y70lV9G7BKPZ4YqsSRtCwy48= ARC-Seal: i=1; a=rsa-sha256; d=hostedemail.com; s=arc-20220608; cv=none; t=1789034623; b=7L23J4EqPTV2HWAwekjuxnIU7s1z/4zt6NqSutoluhDAfr7Vv+oe4aNQYd49aECmP1IIlK AO5MStnKA4cAGfAXT0Fj9e2aQ7CMMz2K5XhPQL0N0W95eMtDBc5KhONUjbPzBY2xp/m7Qs jJ0GCT081snqb2sku+P6tnDsPmskPzg= ARC-Authentication-Results: i=1; imf13.hostedemail.com; dkim=pass header.d=kernel.org header.s=k20260515 header.b=KSilTxny; dmarc=pass (policy=quarantine) header.from=kernel.org; spf=pass (imf13.hostedemail.com: domain of david@kernel.org designates 172.105.4.254 as permitted sender) smtp.mailfrom=david@kernel.org Received: from smtp.kernel.org (quasi.space.kernel.org [100.103.45.18]) by tor.source.kernel.org (Postfix) with ESMTP id C852F600CB; Thu, 10 Sep 2026 10:03:42 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 107771F000FF; Thu, 10 Sep 2026 10:03:30 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=kernel.org; s=k20260515; t=1789034622; bh=d6X874Xrr4USoK1MTGkxBCcI6O6k/kEejm0Rs8M2xgI=; h=Date:Subject:To:Cc:References:From:In-Reply-To; b=KSilTxnykwDLR+U3kjOVLr+CmFJNrFBj+ywnUwLG4EDY6T7i9rZ0/XFHJRAUxB8Cg uqldP1L+oOYwVYS+nTPu9ABsJ/c4y13h6g8tMTZP05a5LhHIQGcJgTz7N4er5qin/P TdDYrSZqPhFpvfWNrCv2w8cKPMKZ2pjwRnlmep6cVJr8RB8MUjJ8ZYY7H4eN8GF7tm z1qahItZ9O9f5fZTHZnfmxkt4xxnbxtyNAUDI3cGONITin5oQR90wv7UX+e7Nn0Tcf +q+DIRfuBfX1UoO8t5Ai2ZyWKSJvKhnAtfQjvp3VJ7tFGlZDMAkXCkaCAaLqSainrz cD2P0SJBso/cg== Message-ID: <8fa1b403-99b0-4508-b705-f9e93c6bf0c8@kernel.org> Date: Thu, 10 Sep 2026 12:03:28 +0200 MIME-Version: 1.0 User-Agent: Mozilla Thunderbird Subject: Re: [PATCH v3 2/9] mm: split AS_UNMOVABLE back out of AS_INACCESSIBLE To: Shivank Garg , "Matthew Wilcox (Oracle)" , Jan Kara , Andrew Morton , Vlastimil Babka , Suren Baghdasaryan , Michal Hocko , Brendan Jackman , Johannes Weiner , Zi Yan , Matthew Brost , Joshua Hahn , Rakie Kim , Byungchul Park , Gregory Price , Ying Huang , Alistair Popple , Paolo Bonzini , Shuah Khan , Chao Peng , Nikunj A Dadhania , Michael Roth , Pankaj Gupta , Ackerley Tng , Sean Christopherson , Vishal Annapurve , Nikita Kalyazin , Patrick Roy , Pratik Sampat , Ashish Kalra , Thomas Gleixner , Ingo Molnar , Borislav Petkov , Dave Hansen , x86@kernel.org, "H. Peter Anvin" , Jonathan Corbet , Shuah Khan , Peter Shier , Jim Mattson , Ricardo Koller , Ira Weiny , Fuad Tabba Cc: linux-fsdevel@vger.kernel.org, linux-coco@lists.linux.dev, linux-mm@kvack.org, linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-kselftest@vger.kernel.org, linux-doc@vger.kernel.org References: <20260805-shivank-gmem-migrate-v3-0-00d8bdec4e1d@amd.com> <20260805-shivank-gmem-migrate-v3-2-00d8bdec4e1d@amd.com> From: "David Hildenbrand (Arm)" Content-Language: en-US Autocrypt: addr=david@kernel.org; keydata= xsFNBFXLn5EBEAC+zYvAFJxCBY9Tr1xZgcESmxVNI/0ffzE/ZQOiHJl6mGkmA1R7/uUpiCjJ dBrn+lhhOYjjNefFQou6478faXE6o2AhmebqT4KiQoUQFV4R7y1KMEKoSyy8hQaK1umALTdL QZLQMzNE74ap+GDK0wnacPQFpcG1AE9RMq3aeErY5tujekBS32jfC/7AnH7I0v1v1TbbK3Gp XNeiN4QroO+5qaSr0ID2sz5jtBLRb15RMre27E1ImpaIv2Jw8NJgW0k/D1RyKCwaTsgRdwuK Kx/Y91XuSBdz0uOyU/S8kM1+ag0wvsGlpBVxRR/xw/E8M7TEwuCZQArqqTCmkG6HGcXFT0V9 PXFNNgV5jXMQRwU0O/ztJIQqsE5LsUomE//bLwzj9IVsaQpKDqW6TAPjcdBDPLHvriq7kGjt WhVhdl0qEYB8lkBEU7V2Yb+SYhmhpDrti9Fq1EsmhiHSkxJcGREoMK/63r9WLZYI3+4W2rAc UucZa4OT27U5ZISjNg3Ev0rxU5UH2/pT4wJCfxwocmqaRr6UYmrtZmND89X0KigoFD/XSeVv jwBRNjPAubK9/k5NoRrYqztM9W6sJqrH8+UWZ1Idd/DdmogJh0gNC0+N42Za9yBRURfIdKSb B3JfpUqcWwE7vUaYrHG1nw54pLUoPG6sAA7Mehl3nd4pZUALHwARAQABzS5EYXZpZCBIaWxk ZW5icmFuZCAoQ3VycmVudCkgPGRhdmlkQGtlcm5lbC5vcmc+wsGQBBMBCAA6AhsDBQkmWAik AgsJBBUKCQgCFgICHgUCF4AWIQQb2cqtc1xMOkYN/MpN3hD3AP+DWgUCaYJt/AIZAQAKCRBN 3hD3AP+DWriiD/9BLGEKG+N8L2AXhikJg6YmXom9ytRwPqDgpHpVg2xdhopoWdMRXjzOrIKD g4LSnFaKneQD0hZhoArEeamG5tyo32xoRsPwkbpIzL0OKSZ8G6mVbFGpjmyDLQCAxteXCLXz ZI0VbsuJKelYnKcXWOIndOrNRvE5eoOfTt2XfBnAapxMYY2IsV+qaUXlO63GgfIOg8RBaj7x 3NxkI3rV0SHhI4GU9K6jCvGghxeS1QX6L/XI9mfAYaIwGy5B68kF26piAVYv/QZDEVIpo3t7 /fjSpxKT8plJH6rhhR0epy8dWRHk3qT5tk2P85twasdloWtkMZ7FsCJRKWscm1BLpsDn6EQ4 jeMHECiY9kGKKi8dQpv3FRyo2QApZ49NNDbwcR0ZndK0XFo15iH708H5Qja/8TuXCwnPWAcJ DQoNIDFyaxe26Rx3ZwUkRALa3iPcVjE0//TrQ4KnFf+lMBSrS33xDDBfevW9+Dk6IISmDH1R HFq2jpkN+FX/PE8eVhV68B2DsAPZ5rUwyCKUXPTJ/irrCCmAAb5Jpv11S7hUSpqtM/6oVESC 3z/7CzrVtRODzLtNgV4r5EI+wAv/3PgJLlMwgJM90Fb3CB2IgbxhjvmB1WNdvXACVydx55V7 LPPKodSTF29rlnQAf9HLgCphuuSrrPn5VQDaYZl4N/7zc2wcWM7BTQRVy5+RARAA59fefSDR 9nMGCb9LbMX+TFAoIQo/wgP5XPyzLYakO+94GrgfZjfhdaxPXMsl2+o8jhp/hlIzG56taNdt VZtPp3ih1AgbR8rHgXw1xwOpuAd5lE1qNd54ndHuADO9a9A0vPimIes78Hi1/yy+ZEEvRkHk /kDa6F3AtTc1m4rbbOk2fiKzzsE9YXweFjQvl9p+AMw6qd/iC4lUk9g0+FQXNdRs+o4o6Qvy iOQJfGQ4UcBuOy1IrkJrd8qq5jet1fcM2j4QvsW8CLDWZS1L7kZ5gT5EycMKxUWb8LuRjxzZ 3QY1aQH2kkzn6acigU3HLtgFyV1gBNV44ehjgvJpRY2cC8VhanTx0dZ9mj1YKIky5N+C0f21 zvntBqcxV0+3p8MrxRRcgEtDZNav+xAoT3G0W4SahAaUTWXpsZoOecwtxi74CyneQNPTDjNg azHmvpdBVEfj7k3p4dmJp5i0U66Onmf6mMFpArvBRSMOKU9DlAzMi4IvhiNWjKVaIE2Se9BY FdKVAJaZq85P2y20ZBd08ILnKcj7XKZkLU5FkoA0udEBvQ0f9QLNyyy3DZMCQWcwRuj1m73D sq8DEFBdZ5eEkj1dCyx+t/ga6x2rHyc8Sl86oK1tvAkwBNsfKou3v+jP/l14a7DGBvrmlYjO 59o3t6inu6H7pt7OL6u6BQj7DoMAEQEAAcLBfAQYAQgAJgIbDBYhBBvZyq1zXEw6Rg38yk3e EPcA/4NaBQJonNqrBQkmWAihAAoJEE3eEPcA/4NaKtMQALAJ8PzprBEXbXcEXwDKQu+P/vts IfUb1UNMfMV76BicGa5NCZnJNQASDP/+bFg6O3gx5NbhHHPeaWz/VxlOmYHokHodOvtL0WCC 8A5PEP8tOk6029Z+J+xUcMrJClNVFpzVvOpb1lCbhjwAV465Hy+NUSbbUiRxdzNQtLtgZzOV Zw7jxUCs4UUZLQTCuBpFgb15bBxYZ/BL9MbzxPxvfUQIPbnzQMcqtpUs21CMK2PdfCh5c4gS sDci6D5/ZIBw94UQWmGpM/O1ilGXde2ZzzGYl64glmccD8e87OnEgKnH3FbnJnT4iJchtSvx yJNi1+t0+qDti4m88+/9IuPqCKb6Stl+s2dnLtJNrjXBGJtsQG/sRpqsJz5x1/2nPJSRMsx9 5YfqbdrJSOFXDzZ8/r82HgQEtUvlSXNaXCa95ez0UkOG7+bDm2b3s0XahBQeLVCH0mw3RAQg r7xDAYKIrAwfHHmMTnBQDPJwVqxJjVNr7yBic4yfzVWGCGNE4DnOW0vcIeoyhy9vnIa3w1uZ 3iyY2Nsd7JxfKu1PRhCGwXzRw5TlfEsoRI7V9A8isUCoqE2Dzh3FvYHVeX4Us+bRL/oqareJ CIFqgYMyvHj7Q06kTKmauOe4Nf0l0qEkIuIzfoLJ3qr5UyXc2hLtWyT9Ir+lYlX9efqh7mOY qIws/H2t In-Reply-To: <20260805-shivank-gmem-migrate-v3-2-00d8bdec4e1d@amd.com> Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit X-Rspam-User: X-Rspamd-Server: rspam06 X-Rspamd-Queue-Id: 80DD120006 X-Stat-Signature: u6kz97qhkecjcs9dm7f7hbuwg597m4bq X-HE-Tag: 1789034623-54128 X-HE-Meta: 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 4U/GxVV4 idwpKV+/1Edt19Kmwpp1bJ1VR1uXVjdnZUbCb7USkvHQh+/JXfHOBnLfVjVFtEH8scVh1pQ7eORIQ0nocaFpJM8w6MPFeopfL8OnArzHOE2YPIWU81xapK0kcL5HzwwQcWamHWhXRcol9IRVr6U5hKRsVE35AkaK7b9wpn+SnQJZirAptajeEpzqEALPxEWZSEGOV0Q5qDkhV+d9vjAoC3/fk/SQ+OR8uVMKhub01Hkl26l3M3KJtMU0IJl/TEFEn8HS6jhRT6Eg0G/XI4xHCsu1jE3zDI3BJUEsS374sGGyUgUrAmc/o6/tW4pGV3n6NpkiuT1Y+cvSr0wZEcADXUvN+fjOH4OK30YvJXgLsuj/T4EJrzoZ5qxHBaj+WzfdjPkdo+bi+3DIQ1Wtb5mohcQZFJg== Sender: owner-linux-mm@kvack.org Precedence: bulk X-Loop: owner-majordomo@kvack.org List-ID: List-Subscribe: List-Unsubscribe: On 8/5/26 08:40, Shivank Garg wrote: > Commit 27e6a24a4cf3 ("mm, virt: merge AS_UNMOVABLE and AS_INACCESSIBLE") > folded the two flags into one, on the grounds that guest_memfd was the > only user and always set both. But the two flags were added for > different reasons and guard different things: > > AS_UNMOVABLE (0003e2a41468) marks a mapping whose folios cannot be > migrated. > > AS_INACCESSIBLE (c72ceafbd12c) marks a mapping whose contents must > not be directly R/W accessed. Its only job is to stop > truncate_inode_partial_folio() from zeroing the folio. > > The merge assumed unmovable and inaccessible were the same thing. > This cannot express a mapping that is inaccessible yet still movable, > which is exactly what guest_memfd wants. > > Reintroduce AS_UNMOVABLE and restore the original split: truncate keeps > checking AS_INACCESSIBLE, while migration and compaction go back to > checking AS_UNMOVABLE. > > Currently guest_memfd sets both, so the resulting flags and behaviour > are unchanged. Preparatory change to support folio migration for > non-confidential guest_memfd VMs. > > Signed-off-by: Shivank Garg > --- > include/linux/pagemap.h | 24 ++++++++++++++++++++---- > mm/compaction.c | 12 ++++++------ > mm/migrate.c | 2 +- > virt/kvm/guest_memfd.c | 1 + > 4 files changed, 28 insertions(+), 11 deletions(-) > > diff --git a/include/linux/pagemap.h b/include/linux/pagemap.h > index 2c3718d592d6..a7dcaa66e4e3 100644 > --- a/include/linux/pagemap.h > +++ b/include/linux/pagemap.h > @@ -210,6 +210,7 @@ enum mapping_flags { > AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM = 9, > AS_KERNEL_FILE = 10, /* mapping for a fake kernel file that shouldn't > account usage to user cgroups */ > + AS_UNMOVABLE = 11, /* The mapping cannot be moved, ever */ > /* Bits 16-25 are used for FOLIO_ORDER */ > AS_FOLIO_ORDER_BITS = 5, > AS_FOLIO_ORDER_MIN = 16, > @@ -322,11 +323,10 @@ static inline void mapping_clear_stable_writes(struct address_space *mapping) > static inline void mapping_set_inaccessible(struct address_space *mapping) > { > /* > - * It's expected inaccessible mappings are also unevictable. Compaction > - * migrate scanner (isolate_migratepages_block()) relies on this to > - * reduce page locking. > + * The mapping's contents must not be accessed by the CPU through > + * the kernel direct map or other internal paths (e.g. zeroing of > + * pages during truncation). > */ > - set_bit(AS_UNEVICTABLE, &mapping->flags); > set_bit(AS_INACCESSIBLE, &mapping->flags); > } > > @@ -335,6 +335,22 @@ static inline bool mapping_inaccessible(const struct address_space *mapping) > return test_bit(AS_INACCESSIBLE, &mapping->flags); > } > > +static inline void mapping_set_unmovable(struct address_space *mapping) > +{ > + /* > + * It's expected unmovable mappings are also unevictable. Compaction > + * migrate scanner (isolate_migratepages_block()) relies on this to > + * reduce page locking. > + */ > + set_bit(AS_UNEVICTABLE, &mapping->flags); > + set_bit(AS_UNMOVABLE, &mapping->flags); > +} > + > +static inline bool mapping_unmovable(const struct address_space *mapping) > +{ > + return test_bit(AS_UNMOVABLE, &mapping->flags); > +} > + > static inline void mapping_set_writeback_may_deadlock_on_reclaim(struct address_space *mapping) > { > set_bit(AS_WRITEBACK_MAY_DEADLOCK_ON_RECLAIM, &mapping->flags); > diff --git a/mm/compaction.c b/mm/compaction.c > index f08765ade014..e6b0fdfaf79d 100644 > --- a/mm/compaction.c > +++ b/mm/compaction.c > @@ -1133,22 +1133,22 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > if (((mode & ISOLATE_ASYNC_MIGRATE) && is_dirty) || > (mapping && is_unevictable)) { > bool migrate_dirty = true; > - bool is_inaccessible; > + bool is_unmovable; > > /* > * Only folios without mappings or that have > * a ->migrate_folio callback are possible to migrate > * without blocking. > * > - * Folios from inaccessible mappings are not migratable. > + * Folios from unmovable mappings are not migratable. > * > * However, we can be racing with truncation, which can > * free the mapping that we need to check. Truncation > * holds the folio lock until after the folio is removed > * from the page so holding it ourselves is sufficient. > * > - * To avoid locking the folio just to check inaccessible, > - * assume every inaccessible folio is also unevictable, > + * To avoid locking the folio just to check unmovable, > + * assume every unmovable folio is also unevictable, > * which is a cheaper test. If our assumption goes > * wrong, it's not a correctness bug, just potentially > * wasted cycles. > @@ -1161,9 +1161,9 @@ isolate_migratepages_block(struct compact_control *cc, unsigned long low_pfn, > migrate_dirty = !mapping || > mapping->a_ops->migrate_folio; > } > - is_inaccessible = mapping && mapping_inaccessible(mapping); > + is_unmovable = mapping && mapping_unmovable(mapping); > folio_unlock(folio); > - if (!migrate_dirty || is_inaccessible) > + if (!migrate_dirty || is_unmovable) > goto isolate_fail_put; > } > > diff --git a/mm/migrate.c b/mm/migrate.c > index dd15a84b2a52..d4dcd7f142ce 100644 > --- a/mm/migrate.c > +++ b/mm/migrate.c > @@ -1101,7 +1101,7 @@ static int move_to_new_folio(struct folio *dst, struct folio *src, > > if (!mapping) > rc = migrate_folio(mapping, dst, src, mode); > - else if (mapping_inaccessible(mapping)) > + else if (mapping_unmovable(mapping)) > rc = -EOPNOTSUPP; > else if (mapping->a_ops->migrate_folio) > /* > diff --git a/virt/kvm/guest_memfd.c b/virt/kvm/guest_memfd.c > index 45cbdf4801ec..169f75f95433 100644 > --- a/virt/kvm/guest_memfd.c > +++ b/virt/kvm/guest_memfd.c > @@ -593,6 +593,7 @@ static int __kvm_gmem_create(struct kvm *kvm, loff_t size, u64 flags) > inode->i_size = size; > mapping_set_gfp_mask(inode->i_mapping, GFP_HIGHUSER); > mapping_set_inaccessible(inode->i_mapping); > + mapping_set_unmovable(inode->i_mapping); For shared-only guest_memfd, is there even a reason to mark it as mapping_set_inaccessible() ? mapping_inaccessible() is only used in truncation and compaction logic. Wouldn't we want compaction to work here? IOW, for shared-only with migration support, can't we just not do mapping_set_inaccessible() ? -- Cheers, David