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 13AA9C05027 for ; Thu, 26 Jan 2023 23:10:16 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S229948AbjAZXKP (ORCPT ); Thu, 26 Jan 2023 18:10:15 -0500 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:34598 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233310AbjAZXKL (ORCPT ); Thu, 26 Jan 2023 18:10:11 -0500 Received: from ams.source.kernel.org (ams.source.kernel.org [145.40.68.75]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1EF7623C7F for ; Thu, 26 Jan 2023 15:10:09 -0800 (PST) Received: from smtp.kernel.org (relay.kernel.org [52.25.139.140]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by ams.source.kernel.org (Postfix) with ESMTPS id BB4CAB81F2F for ; Thu, 26 Jan 2023 23:10:07 +0000 (UTC) Received: by smtp.kernel.org (Postfix) with ESMTPSA id 5D2BCC433D2; Thu, 26 Jan 2023 23:10:06 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=linux-foundation.org; s=korg; t=1674774606; bh=5YtQ4SvZ2WA2a/uOwZCiakcg2Tju58tKuOyVw/G4Wcs=; h=Date:To:From:Subject:From; b=QklSg6h+F+CDR/GxEb8H/7uUJIBohH9YddRhZzqT8edS4RZuF4JO496OBuDG71ub3 SvcPPGq1gkLoZiviywWbrZzM1Av10MOLtFNK1cpHxEZi7qy/w1oxR7xg4cod5wIDpR TxqPENN2DfmqtCVNDBMvq48MOJ7yCO4sqpeCCFWk= Date: Thu, 26 Jan 2023 15:10:05 -0800 To: mm-commits@vger.kernel.org, willy@infradead.org, will@kernel.org, vbabka@suse.cz, songliubraving@fb.com, soheil@google.com, shakeelb@google.com, sebastian.reichel@collabora.com, rppt@kernel.org, rientjes@google.com, punit.agrawal@bytedance.com, posk@google.com, peterz@infradead.org, peterx@redhat.com, paulmck@kernel.org, mingo@redhat.com, minchan@google.com, mhocko@suse.com, mgorman@techsingularity.net, luto@kernel.org, lstoakes@gmail.com, Liam.Howlett@Oracle.com, ldufour@linux.ibm.com, kent.overstreet@linux.dev, joelaf@google.com, jannh@google.com, hughd@google.com, hannes@cmpxchg.org, gthelen@google.com, edumazet@google.com, dhowells@redhat.com, david@redhat.com, dave@stgolabs.net, bigeasy@linutronix.de, axelrasmussen@google.com, arjunroy@google.com, surenb@google.com, akpm@linux-foundation.org From: Andrew Morton Subject: + mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn.patch added to mm-unstable branch Message-Id: <20230126231006.5D2BCC433D2@smtp.kernel.org> Precedence: bulk Reply-To: linux-kernel@vger.kernel.org List-ID: X-Mailing-List: mm-commits@vger.kernel.org The patch titled Subject: mm: introduce __vm_flags_mod and use it in untrack_pfn has been added to the -mm mm-unstable branch. Its filename is mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn.patch This patch will shortly appear at https://git.kernel.org/pub/scm/linux/kernel/git/akpm/25-new.git/tree/patches/mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn.patch This patch will later appear in the mm-unstable branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm Before you just go and hit "reply", please: a) Consider who else should be cc'ed b) Prefer to cc a suitable mailing list as well c) Ideally: find the original patch on the mailing list and do a reply-to-all to that, adding suitable additional cc's *** Remember to use Documentation/process/submit-checklist.rst when testing your code *** The -mm tree is included into linux-next via the mm-everything branch at git://git.kernel.org/pub/scm/linux/kernel/git/akpm/mm and is updated there every 2-3 working days ------------------------------------------------------ From: Suren Baghdasaryan Subject: mm: introduce __vm_flags_mod and use it in untrack_pfn Date: Thu, 26 Jan 2023 11:37:51 -0800 There are scenarios when vm_flags can be modified without exclusive mmap_lock, such as: - after VMA was isolated and mmap_lock was downgraded or dropped - in exit_mmap when there are no other mm users and locking is unnecessary Introduce __vm_flags_mod to avoid assertions when the caller takes responsibility for the required locking. Pass a hint to untrack_pfn to conditionally use __vm_flags_mod for flags modification to avoid assertion. Link: https://lkml.kernel.org/r/20230126193752.297968-7-surenb@google.com Signed-off-by: Suren Baghdasaryan Acked-by: Michal Hocko Acked-by: Mike Rapoport (IBM) Cc: Andy Lutomirski Cc: Arjun Roy Cc: Axel Rasmussen Cc: David Hildenbrand Cc: David Howells Cc: Davidlohr Bueso Cc: David Rientjes Cc: Eric Dumazet Cc: Greg Thelen Cc: Hugh Dickins Cc: Ingo Molnar Cc: Jann Horn Cc: Joel Fernandes Cc: Johannes Weiner Cc: Kent Overstreet Cc: Laurent Dufour Cc: Liam R. Howlett Cc: Lorenzo Stoakes Cc: Matthew Wilcox Cc: Mel Gorman Cc: Minchan Kim Cc: Paul E. McKenney Cc: Peter Oskolkov Cc: Peter Xu Cc: Peter Zijlstra Cc: Punit Agrawal Cc: Sebastian Andrzej Siewior Cc: Sebastian Reichel Cc: Shakeel Butt Cc: Soheil Hassas Yeganeh Cc: Song Liu Cc: Vlastimil Babka Cc: Will Deacon Signed-off-by: Andrew Morton --- arch/x86/mm/pat/memtype.c | 10 +++++++--- include/linux/mm.h | 14 ++++++++++++-- include/linux/pgtable.h | 5 +++-- mm/memory.c | 13 +++++++------ mm/memremap.c | 4 ++-- mm/mmap.c | 16 ++++++++++------ 6 files changed, 41 insertions(+), 21 deletions(-) --- a/arch/x86/mm/pat/memtype.c~mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn +++ a/arch/x86/mm/pat/memtype.c @@ -1046,7 +1046,7 @@ void track_pfn_insert(struct vm_area_str * can be for the entire vma (in which case pfn, size are zero). */ void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, - unsigned long size) + unsigned long size, bool mm_wr_locked) { resource_size_t paddr; unsigned long prot; @@ -1065,8 +1065,12 @@ void untrack_pfn(struct vm_area_struct * size = vma->vm_end - vma->vm_start; } free_pfn_range(paddr, size); - if (vma) - vm_flags_clear(vma, VM_PAT); + if (vma) { + if (mm_wr_locked) + vm_flags_clear(vma, VM_PAT); + else + __vm_flags_mod(vma, 0, VM_PAT); + } } /* --- a/include/linux/mm.h~mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn +++ a/include/linux/mm.h @@ -657,6 +657,16 @@ static inline void vm_flags_clear(struct } /* + * Use only if VMA is not part of the VMA tree or has no other users and + * therefore needs no locking. + */ +static inline void __vm_flags_mod(struct vm_area_struct *vma, + vm_flags_t set, vm_flags_t clear) +{ + vm_flags_init(vma, (vma->vm_flags | set) & ~clear); +} + +/* * Use only when the order of set/clear operations is unimportant, otherwise * use vm_flags_{set|clear} explicitly. */ @@ -664,7 +674,7 @@ static inline void vm_flags_mod(struct v vm_flags_t set, vm_flags_t clear) { mmap_assert_write_locked(vma->vm_mm); - vm_flags_init(vma, (vma->vm_flags | set) & ~clear); + __vm_flags_mod(vma, set, clear); } static inline void vma_set_anonymous(struct vm_area_struct *vma) @@ -2102,7 +2112,7 @@ static inline void zap_vma_pages(struct } void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, struct vm_area_struct *start_vma, unsigned long start, - unsigned long end); + unsigned long end, bool mm_wr_locked); struct mmu_notifier_range; --- a/include/linux/pgtable.h~mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn +++ a/include/linux/pgtable.h @@ -1185,7 +1185,8 @@ static inline int track_pfn_copy(struct * can be for the entire vma (in which case pfn, size are zero). */ static inline void untrack_pfn(struct vm_area_struct *vma, - unsigned long pfn, unsigned long size) + unsigned long pfn, unsigned long size, + bool mm_wr_locked) { } @@ -1203,7 +1204,7 @@ extern void track_pfn_insert(struct vm_a pfn_t pfn); extern int track_pfn_copy(struct vm_area_struct *vma); extern void untrack_pfn(struct vm_area_struct *vma, unsigned long pfn, - unsigned long size); + unsigned long size, bool mm_wr_locked); extern void untrack_pfn_moved(struct vm_area_struct *vma); #endif --- a/mm/memory.c~mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn +++ a/mm/memory.c @@ -1613,7 +1613,7 @@ void unmap_page_range(struct mmu_gather static void unmap_single_vma(struct mmu_gather *tlb, struct vm_area_struct *vma, unsigned long start_addr, unsigned long end_addr, - struct zap_details *details) + struct zap_details *details, bool mm_wr_locked) { unsigned long start = max(vma->vm_start, start_addr); unsigned long end; @@ -1628,7 +1628,7 @@ static void unmap_single_vma(struct mmu_ uprobe_munmap(vma, start, end); if (unlikely(vma->vm_flags & VM_PFNMAP)) - untrack_pfn(vma, 0, 0); + untrack_pfn(vma, 0, 0, mm_wr_locked); if (start != end) { if (unlikely(is_vm_hugetlb_page(vma))) { @@ -1675,7 +1675,7 @@ static void unmap_single_vma(struct mmu_ */ void unmap_vmas(struct mmu_gather *tlb, struct maple_tree *mt, struct vm_area_struct *vma, unsigned long start_addr, - unsigned long end_addr) + unsigned long end_addr, bool mm_wr_locked) { struct mmu_notifier_range range; struct zap_details details = { @@ -1689,7 +1689,8 @@ void unmap_vmas(struct mmu_gather *tlb, start_addr, end_addr); mmu_notifier_invalidate_range_start(&range); do { - unmap_single_vma(tlb, vma, start_addr, end_addr, &details); + unmap_single_vma(tlb, vma, start_addr, end_addr, &details, + mm_wr_locked); } while ((vma = mas_find(&mas, end_addr - 1)) != NULL); mmu_notifier_invalidate_range_end(&range); } @@ -1723,7 +1724,7 @@ void zap_page_range_single(struct vm_are * unmap 'address-end' not 'range.start-range.end' as range * could have been expanded for hugetlb pmd sharing. */ - unmap_single_vma(&tlb, vma, address, end, details); + unmap_single_vma(&tlb, vma, address, end, details, false); mmu_notifier_invalidate_range_end(&range); tlb_finish_mmu(&tlb); } @@ -2492,7 +2493,7 @@ int remap_pfn_range(struct vm_area_struc err = remap_pfn_range_notrack(vma, addr, pfn, size, prot); if (err) - untrack_pfn(vma, pfn, PAGE_ALIGN(size)); + untrack_pfn(vma, pfn, PAGE_ALIGN(size), true); return err; } EXPORT_SYMBOL(remap_pfn_range); --- a/mm/memremap.c~mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn +++ a/mm/memremap.c @@ -129,7 +129,7 @@ static void pageunmap_range(struct dev_p } mem_hotplug_done(); - untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range)); + untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true); pgmap_array_delete(range); } @@ -276,7 +276,7 @@ err_add_memory: if (!is_private) kasan_remove_zero_shadow(__va(range->start), range_len(range)); err_kasan: - untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range)); + untrack_pfn(NULL, PHYS_PFN(range->start), range_len(range), true); err_pfn_remap: pgmap_array_delete(range); return error; --- a/mm/mmap.c~mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn +++ a/mm/mmap.c @@ -78,7 +78,7 @@ core_param(ignore_rlimit_data, ignore_rl static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next, unsigned long start, - unsigned long end); + unsigned long end, bool mm_wr_locked); static pgprot_t vm_pgprot_modify(pgprot_t oldprot, unsigned long vm_flags) { @@ -2133,14 +2133,14 @@ static inline void remove_mt(struct mm_s static void unmap_region(struct mm_struct *mm, struct maple_tree *mt, struct vm_area_struct *vma, struct vm_area_struct *prev, struct vm_area_struct *next, - unsigned long start, unsigned long end) + unsigned long start, unsigned long end, bool mm_wr_locked) { struct mmu_gather tlb; lru_add_drain(); tlb_gather_mmu(&tlb, mm); update_hiwater_rss(mm); - unmap_vmas(&tlb, mt, vma, start, end); + unmap_vmas(&tlb, mt, vma, start, end, mm_wr_locked); free_pgtables(&tlb, mt, vma, prev ? prev->vm_end : FIRST_USER_ADDRESS, next ? next->vm_start : USER_PGTABLES_CEILING); tlb_finish_mmu(&tlb); @@ -2388,7 +2388,11 @@ do_vmi_align_munmap(struct vma_iterator mmap_write_downgrade(mm); } - unmap_region(mm, &mt_detach, vma, prev, next, start, end); + /* + * We can free page tables without write-locking mmap_lock because VMAs + * were isolated before we downgraded mmap_lock. + */ + unmap_region(mm, &mt_detach, vma, prev, next, start, end, !downgrade); /* Statistics and freeing VMAs */ mas_set(&mas_detach, start); remove_mt(mm, &mas_detach); @@ -2701,7 +2705,7 @@ unmap_and_free_vma: /* Undo any partial mapping done by a device driver. */ unmap_region(mm, &mm->mm_mt, vma, prev, next, vma->vm_start, - vma->vm_end); + vma->vm_end, true); } if (file && (vm_flags & VM_SHARED)) mapping_unmap_writable(file->f_mapping); @@ -3029,7 +3033,7 @@ void exit_mmap(struct mm_struct *mm) tlb_gather_mmu_fullmm(&tlb, mm); /* update_hiwater_rss(mm) here? but nobody should be looking */ /* Use ULONG_MAX here to ensure all VMAs in the mm are unmapped */ - unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX); + unmap_vmas(&tlb, &mm->mm_mt, vma, 0, ULONG_MAX, false); mmap_read_unlock(mm); /* _ Patches currently in -mm which might be from surenb@google.com are kernel-fork-convert-vma-assignment-to-a-memcpy.patch mm-introduce-vma-vm_flags-wrapper-functions.patch mm-replace-vm_locked_clear_mask-with-vm_locked_mask.patch mm-replace-vma-vm_flags-direct-modifications-with-modifier-calls.patch mm-replace-vma-vm_flags-indirect-modification-in-ksm_madvise.patch mm-introduce-__vm_flags_mod-and-use-it-in-untrack_pfn.patch mm-export-dump_mm.patch