From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from smtp.kernel.org (aws-us-west-2-korg-mail-1.web.codeaurora.org [10.30.226.201]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.subspace.kernel.org (Postfix) with ESMTPS id 5C42F21518D for ; Mon, 17 Mar 2025 05:10:06 +0000 (UTC) Authentication-Results: smtp.subspace.kernel.org; arc=none smtp.client-ip=10.30.226.201 ARC-Seal:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742188206; cv=none; b=cZM92m2/tzSn85sgV9PIDTCU+INIQOmWunW/T1BmTZTiyK3BZ9SzX8MZUBfhp0w3Em9WlANvLMH5VhJ3QsjJabcQonaahz8fXbxPHTXHngVfiuwp44dFJaYN8ixUIg8cx2FeH4/QYwQ5QfPPZqJhrXcy5xNWmaMcKT+Q/tTXPCw= ARC-Message-Signature:i=1; a=rsa-sha256; d=subspace.kernel.org; s=arc-20240116; t=1742188206; c=relaxed/simple; bh=yxZK+hfAU+1YUYB5YdOZr0xYfPHpy2RjI0MlfaJnwac=; h=Date:To:From:Subject:Message-Id; b=hte2Zl7dnTPfz1HdnDUXDqAJ47YeeXYA/EU0PX2qAIgC1UtlFHJ9fXr9RI77H6cbq7jFJiCYkiIqSGByyHAA4Zr2xScfqBMwj05X/svm6mowIVBEg/RJv1fGfIIBoHt84jjrEjeyZl7se843oBSm57YW42iz3pB0oFc+T7E5VS0= ARC-Authentication-Results:i=1; smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b=VFLMfv4F; arc=none smtp.client-ip=10.30.226.201 Authentication-Results: smtp.subspace.kernel.org; dkim=pass (1024-bit key) header.d=linux-foundation.org header.i=@linux-foundation.org header.b="VFLMfv4F" Received: by smtp.kernel.org (Postfix) with ESMTPSA id 276C6C4CEEC; Mon, 17 Mar 2025 05:10:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1742188206; bh=yxZK+hfAU+1YUYB5YdOZr0xYfPHpy2RjI0MlfaJnwac=; h=Date:To:From:Subject:From; b=VFLMfv4FfJ/h1lgQyzEg11IW2UtlXY1We6cY47TYh2IQ1A2GFhJHaFFNcGZyh7DlL S0yeA4KdJlLqmHh11IGtCco52ey4f+7W7cH56fAB9yx+liTRmF3Sm0HM+ekfskzUku wb9rLnCN7mPLiej+HqK05YuaIv69XCKFjwMhZZvU= Date: Sun, 16 Mar 2025 22:10:05 -0700 To: mm-commits@vger.kernel.org,v-songbaohua@oppo.com,vbabka@suse.cz,sj@kernel.org,si.yanteng@linux.dev,simona.vetter@ffwll.ch,peterz@infradead.org,peterx@redhat.com,pasha.tatashin@soleen.com,oleg@redhat.com,mhiramat@kernel.org,lyude@redhat.com,lorenzo.stoakes@oracle.com,liam.howlett@oracle.com,kherbst@redhat.com,jhubbard@nvidia.com,jglisse@redhat.com,jgg@nvidia.com,jannh@google.com,dakr@kernel.org,corbet@lwn.net,apopple@nvidia.com,alexs@kernel.org,airlied@gmail.com,david@redhat.com,akpm@linux-foundation.org From: Andrew Morton Subject: [merged mm-stable] mm-rmap-keep-mapcount-untouched-for-device-exclusive-entries.patch removed from -mm tree Message-Id: <20250317051006.276C6C4CEEC@smtp.kernel.org> Precedence: bulk X-Mailing-List: mm-commits@vger.kernel.org List-Id: List-Subscribe: List-Unsubscribe: The quilt patch titled Subject: mm/rmap: keep mapcount untouched for device-exclusive entries has been removed from the -mm tree. Its filename was mm-rmap-keep-mapcount-untouched-for-device-exclusive-entries.patch This patch was dropped because it was merged into the mm-stable branch of git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm ------------------------------------------------------ From: David Hildenbrand Subject: mm/rmap: keep mapcount untouched for device-exclusive entries Date: Mon, 10 Feb 2025 20:37:58 +0100 Now that conversion to device-exclusive does no longer perform an rmap walk and all page_vma_mapped_walk() users were taught to properly handle device-exclusive entries, let's treat device-exclusive entries just as if they would be present, similar to how we handle device-private entries already. This fixes swapout/migration/split/hwpoison of folios with device-exclusive entries. We only had to take care of page_vma_mapped_walk() users, because these traditionally assume pte_present(). Other page table walkers already have to handle !pte_present(), and some of them might simply skip them (e.g., MADV_PAGEOUT) if they are not specialized on them. This change doesn't modify the latter. Note that while folios with device-exclusive PTEs can now get migrated, khugepaged will not collapse a THP if there is device-exclusive PTE. Doing so might also not be desired if the device frequently performs atomics to the same page. Similarly, KSM will never merge order-0 folios that are device-exclusive. Link: https://lkml.kernel.org/r/20250210193801.781278-17-david@redhat.com Fixes: b756a3b5e7ea ("mm: device exclusive memory access") Signed-off-by: David Hildenbrand Tested-by: Alistair Popple Cc: Alex Shi Cc: Danilo Krummrich Cc: Dave Airlie Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jerome Glisse Cc: John Hubbard Cc: Jonathan Corbet Cc: Karol Herbst Cc: Liam Howlett Cc: Lorenzo Stoakes Cc: Lyude Cc: "Masami Hiramatsu (Google)" Cc: Oleg Nesterov Cc: Pasha Tatashin Cc: Peter Xu Cc: Peter Zijlstra (Intel) Cc: SeongJae Park Cc: Simona Vetter Cc: Vlastimil Babka Cc: Yanteng Si Cc: Barry Song Signed-off-by: Andrew Morton --- mm/memory.c | 17 +---------------- mm/rmap.c | 7 ------- 2 files changed, 1 insertion(+), 23 deletions(-) --- a/mm/memory.c~mm-rmap-keep-mapcount-untouched-for-device-exclusive-entries +++ a/mm/memory.c @@ -741,20 +741,6 @@ static void restore_exclusive_pte(struct VM_BUG_ON_FOLIO(pte_write(pte) && (!folio_test_anon(folio) && PageAnonExclusive(page)), folio); - - /* - * No need to take a page reference as one was already - * created when the swap entry was made. - */ - if (folio_test_anon(folio)) - folio_add_anon_rmap_pte(folio, page, vma, address, RMAP_NONE); - else - /* - * Currently device exclusive access only supports anonymous - * memory so the entry shouldn't point to a filebacked page. - */ - WARN_ON_ONCE(1); - set_pte_at(vma->vm_mm, address, ptep, pte); /* @@ -1626,8 +1612,7 @@ static inline int zap_nonpresent_ptes(st */ WARN_ON_ONCE(!vma_is_anonymous(vma)); rss[mm_counter(folio)]--; - if (is_device_private_entry(entry)) - folio_remove_rmap_pte(folio, page, vma); + folio_remove_rmap_pte(folio, page, vma); folio_put(folio); } else if (!non_swap_entry(entry)) { /* Genuine swap entries, hence a private anon pages */ --- a/mm/rmap.c~mm-rmap-keep-mapcount-untouched-for-device-exclusive-entries +++ a/mm/rmap.c @@ -2511,13 +2511,6 @@ struct page *make_device_exclusive(struc /* The pte is writable, uffd-wp does not apply. */ set_pte_at(mm, addr, fw.ptep, swp_pte); - /* - * TODO: The device-exclusive PFN swap PTE holds a folio reference but - * does not count as a mapping (mapcount), which is wrong and must be - * fixed, otherwise RMAP walks don't behave as expected. - */ - folio_remove_rmap_pte(folio, page, vma); - folio_walk_end(&fw, vma); mmu_notifier_invalidate_range_end(&range); *foliop = folio; _ Patches currently in -mm which might be from david@redhat.com are mm-factor-out-large-folio-handling-from-folio_order-into-folio_large_order.patch mm-factor-out-large-folio-handling-from-folio_nr_pages-into-folio_large_nr_pages.patch mm-let-_folio_nr_pages-overlay-memcg_data-in-first-tail-page.patch mm-let-_folio_nr_pages-overlay-memcg_data-in-first-tail-page-fix.patch mm-move-hugetlb-specific-things-in-folio-to-page.patch mm-move-_pincount-in-folio-to-page-on-32bit.patch mm-move-_entire_mapcount-in-folio-to-page-on-32bit.patch mm-rmap-pass-dst_vma-to-folio_dup_file_rmap_pte-and-friends.patch mm-rmap-pass-vma-to-__folio_add_rmap.patch mm-rmap-abstract-large-mapcount-operations-for-large-folios-hugetlb.patch bit_spinlock-__always_inline-unlock-functions.patch mm-rmap-use-folio_large_nr_pages-in-add-remove-functions.patch mm-rmap-basic-mm-owner-tracking-for-large-folios-hugetlb.patch mm-copy-on-write-cow-reuse-support-for-pte-mapped-thp.patch mm-convert-folio_likely_mapped_shared-to-folio_maybe_mapped_shared.patch mm-config_no_page_mapcount-to-prepare-for-not-maintain-per-page-mapcounts-in-large-folios.patch fs-proc-page-remove-per-page-mapcount-dependency-for-proc-kpagecount-config_no_page_mapcount.patch fs-proc-task_mmu-remove-per-page-mapcount-dependency-for-pm_mmap_exclusive-config_no_page_mapcount.patch fs-proc-task_mmu-remove-per-page-mapcount-dependency-for-mapmax-config_no_page_mapcount.patch fs-proc-task_mmu-remove-per-page-mapcount-dependency-for-smaps-smaps_rollup-config_no_page_mapcount.patch mm-stop-maintaining-the-per-page-mapcount-of-large-folios-config_no_page_mapcount.patch