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From: Michal Hocko <mhocko@suse.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, michel@lespinasse.org,
	jglisse@google.com, vbabka@suse.cz, hannes@cmpxchg.org,
	mgorman@techsingularity.net, dave@stgolabs.net,
	willy@infradead.org, liam.howlett@oracle.com,
	peterz@infradead.org, ldufour@linux.ibm.com,
	laurent.dufour@fr.ibm.com, paulmck@kernel.org, luto@kernel.org,
	songliubraving@fb.com, peterx@redhat.com, david@redhat.com,
	dhowells@redhat.com, hughd@google.com, bigeasy@linutronix.de,
	kent.overstreet@linux.dev, punit.agrawal@bytedance.com,
	lstoakes@gmail.com, peterjung1337@gmail.com, rientjes@google.com,
	axelrasmussen@google.com, joelaf@google.com, minchan@google.com,
	jannh@google.com, shakeelb@google.com, tatashin@google.com,
	edumazet@google.com, gthelen@google.com, gurua@google.com,
	arjunroy@google.com, soheil@google.com, hughlynch@google.com,
	leewalsh@google.com, posk@google.com, linux-mm@kvack.org,
	linux-arm-kernel@lists.infradead.org,
	linuxppc-dev@lists.ozlabs.org, x86@kernel.org,
	linux-kernel@vger.kernel.org, kernel-team@android.com
Subject: Re: [PATCH 17/41] mm/mmap: move VMA locking before anon_vma_lock_write call
Date: Wed, 18 Jan 2023 22:33:39 +0100	[thread overview]
Message-ID: <Y8hls4MH353ZnlQu@dhcp22.suse.cz> (raw)
In-Reply-To: <CAJuCfpHtV5xEo97X62uR=LXjK6wQMJXhhV2OxXexTfyudGOptw@mail.gmail.com>

On Wed 18-01-23 10:09:29, Suren Baghdasaryan wrote:
> On Wed, Jan 18, 2023 at 1:23 AM Michal Hocko <mhocko@suse.com> wrote:
> >
> > On Tue 17-01-23 18:01:01, Suren Baghdasaryan wrote:
> > > On Tue, Jan 17, 2023 at 7:16 AM Michal Hocko <mhocko@suse.com> wrote:
> > > >
> > > > On Mon 09-01-23 12:53:12, Suren Baghdasaryan wrote:
> > > > > Move VMA flag modification (which now implies VMA locking) before
> > > > > anon_vma_lock_write to match the locking order of page fault handler.
> > > >
> > > > Does this changelog assumes per vma locking in the #PF?
> > >
> > > Hmm, you are right. Page fault handlers do not use per-vma locks yet
> > > but the changelog already talks about that. Maybe I should change it
> > > to simply:
> > > ```
> > > Move VMA flag modification (which now implies VMA locking) before
> > > vma_adjust_trans_huge() to ensure the modifications are done after VMA
> > > has been locked.
> >
> > Because ....
> 
> because vma_adjust_trans_huge() modifies the VMA and such
> modifications should be done under VMA write-lock protection.

So it will become:
Move VMA flag modification (which now implies VMA locking) before
vma_adjust_trans_huge() to ensure the modifications are done after VMA
has been locked. Because vma_adjust_trans_huge() modifies the VMA and such
modifications should be done under VMA write-lock protection.

which is effectivelly saying
vma_adjust_trans_huge() modifies the VMA and such modifications should
be done under VMA write-lock protection so move VMA flag modifications
before so all of them are covered by the same write protection.

right?
-- 
Michal Hocko
SUSE Labs

  reply	other threads:[~2023-01-18 21:33 UTC|newest]

Thread overview: 186+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2023-01-09 20:52 [PATCH 00/41] Per-VMA locks Suren Baghdasaryan
2023-01-09 20:52 ` [PATCH 01/41] maple_tree: Be more cautious about dead nodes Suren Baghdasaryan
2023-01-09 20:52 ` [PATCH 02/41] maple_tree: Detect dead nodes in mas_start() Suren Baghdasaryan
2023-01-09 20:52 ` [PATCH 03/41] maple_tree: Fix freeing of nodes in rcu mode Suren Baghdasaryan
2023-01-09 20:52 ` [PATCH 04/41] maple_tree: remove extra smp_wmb() from mas_dead_leaves() Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 05/41] maple_tree: Fix write memory barrier of nodes once dead for RCU mode Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 06/41] maple_tree: Add smp_rmb() to dead node detection Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 07/41] mm: Enable maple tree RCU mode by default Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 08/41] mm: introduce CONFIG_PER_VMA_LOCK Suren Baghdasaryan
2023-01-11  0:13   ` Davidlohr Bueso
2023-01-11  0:44     ` Suren Baghdasaryan
2023-01-11  8:23       ` Michal Hocko
2023-01-11  9:54         ` Ingo Molnar
     [not found]           ` <6be809f5554a4faaa22c287ba4224bd0@AcuMS.aculab.com>
2023-01-11 16:28             ` Suren Baghdasaryan
2023-01-11 16:44               ` Michal Hocko
2023-01-11 17:04                 ` Suren Baghdasaryan
2023-01-11 17:37                   ` Michal Hocko
2023-01-11 17:49                     ` Suren Baghdasaryan
2023-01-11 18:02                       ` Michal Hocko
2023-01-11 18:09                         ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 09/41] mm: rcu safe VMA freeing Suren Baghdasaryan
2023-01-17 14:25   ` Michal Hocko
2023-01-18  2:16     ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 10/41] mm: move mmap_lock assert function definitions Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 11/41] mm: export dump_mm() Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 12/41] mm: add per-VMA lock and helper functions to control it Suren Baghdasaryan
2023-01-17 15:04   ` Michal Hocko
2023-01-17 15:12     ` Michal Hocko
2023-01-17 21:21       ` Suren Baghdasaryan
2023-01-17 21:54         ` Matthew Wilcox
2023-01-17 22:33           ` Suren Baghdasaryan
2023-01-18  9:18           ` Michal Hocko
2023-01-17 21:08     ` Suren Baghdasaryan
2023-01-17 15:07   ` Michal Hocko
2023-01-17 21:09     ` Suren Baghdasaryan
2023-01-17 18:02   ` Jann Horn
2023-01-17 21:28     ` Suren Baghdasaryan
2023-01-17 21:45       ` Jann Horn
2023-01-17 22:36         ` Suren Baghdasaryan
2023-01-17 23:15           ` Matthew Wilcox
2023-11-22 14:04         ` Alexander Gordeev
2023-01-18 12:28     ` Michal Hocko
2023-01-18 13:23       ` Jann Horn
2023-01-18 15:11         ` Michal Hocko
2023-01-18 17:36           ` Suren Baghdasaryan
2023-01-18 21:28             ` Michal Hocko
2023-01-18 21:45               ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 13/41] mm: introduce vma->vm_flags modifier functions Suren Baghdasaryan
2023-01-11 15:47   ` Davidlohr Bueso
2023-01-11 17:36     ` Suren Baghdasaryan
2023-01-11 19:52       ` Davidlohr Bueso
2023-01-11 21:23         ` Suren Baghdasaryan
2023-01-17 15:09   ` Michal Hocko
2023-01-17 15:15     ` Michal Hocko
2023-01-18  2:07       ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 14/41] mm: replace VM_LOCKED_CLEAR_MASK with VM_LOCKED_MASK Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 15/41] mm: replace vma->vm_flags direct modifications with modifier calls Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 16/41] mm: replace vma->vm_flags indirect modification in ksm_madvise Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 17/41] mm/mmap: move VMA locking before anon_vma_lock_write call Suren Baghdasaryan
2023-01-17 15:16   ` Michal Hocko
2023-01-18  2:01     ` Suren Baghdasaryan
2023-01-18  9:23       ` Michal Hocko
2023-01-18 18:09         ` Suren Baghdasaryan
2023-01-18 21:33           ` Michal Hocko [this message]
2023-01-18 21:48             ` Suren Baghdasaryan
2023-01-19  9:31               ` Michal Hocko
2023-01-19 18:53                 ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 18/41] mm/khugepaged: write-lock VMA while collapsing a huge page Suren Baghdasaryan
2023-01-17 15:25   ` Michal Hocko
2023-01-17 20:28     ` Jann Horn
2023-01-17 21:05       ` Suren Baghdasaryan
2023-01-18  9:40       ` Michal Hocko
2023-01-18 12:38         ` Jann Horn
2023-01-18 17:41         ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 19/41] mm/mmap: write-lock VMAs before merging, splitting or expanding them Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 20/41] mm/mmap: write-lock VMAs in vma_adjust Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 21/41] mm/mmap: write-lock VMAs affected by VMA expansion Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 22/41] mm/mremap: write-lock VMA while remapping it to a new address range Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 23/41] mm: write-lock VMAs before removing them from VMA tree Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 24/41] mm: conditionally write-lock VMA in free_pgtables Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 25/41] mm/mmap: write-lock adjacent VMAs if they can grow into unmapped area Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 26/41] kernel/fork: assert no VMA readers during its destruction Suren Baghdasaryan
2023-01-17 15:42   ` Michal Hocko
2023-01-18  1:53     ` Suren Baghdasaryan
2023-01-18  9:43       ` Michal Hocko
2023-01-18 18:06         ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 27/41] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration Suren Baghdasaryan
2023-01-18 12:50   ` Jann Horn
2023-01-18 17:40     ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 28/41] mm: introduce lock_vma_under_rcu to be used from arch-specific code Suren Baghdasaryan
2023-01-17 15:47   ` Michal Hocko
2023-01-18  1:06     ` Suren Baghdasaryan
2023-01-18  2:44       ` Matthew Wilcox
2023-01-18 21:33         ` Suren Baghdasaryan
2023-01-17 21:03   ` Jann Horn
2023-01-17 23:18     ` Liam Howlett
2023-01-09 20:53 ` [PATCH 29/41] mm: fall back to mmap_lock if vma->anon_vma is not yet set Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 30/41] mm: add FAULT_FLAG_VMA_LOCK flag Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 31/41] mm: prevent do_swap_page from handling page faults under VMA lock Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 32/41] mm: prevent userfaults to be handled under per-vma lock Suren Baghdasaryan
2023-01-17 19:51   ` Jann Horn
2023-01-17 20:36     ` Jann Horn
2023-01-17 20:57       ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 33/41] mm: introduce per-VMA lock statistics Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 34/41] x86/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 35/41] arm64/mm: " Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 36/41] powerc/mm: " Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 37/41] mm: introduce mod_vm_flags_nolock Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 38/41] mm: avoid assertion in untrack_pfn Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 39/41] kernel/fork: throttle call_rcu() calls in vm_area_free Suren Baghdasaryan
2023-01-17 15:57   ` Michal Hocko
2023-01-18  1:19     ` Suren Baghdasaryan
2023-01-18  9:49       ` Michal Hocko
2023-01-18 18:04         ` Suren Baghdasaryan
2023-01-18 18:34           ` Paul E. McKenney
2023-01-18 19:01             ` Suren Baghdasaryan
2023-01-18 20:20               ` Paul E. McKenney
2023-01-19 12:52               ` Michal Hocko
2023-01-19 19:17                 ` Paul E. McKenney
2023-01-20  8:57                   ` Michal Hocko
2023-01-20 16:08                     ` Paul E. McKenney
2023-01-19 12:59   ` Michal Hocko
2023-01-19 18:52     ` Suren Baghdasaryan
2023-01-19 19:20       ` Paul E. McKenney
2023-01-19 19:47         ` Suren Baghdasaryan
2023-01-19 19:55           ` Paul E. McKenney
2023-01-20  8:52       ` Michal Hocko
2023-01-20 16:20         ` Suren Baghdasaryan
2023-01-20 16:45           ` Suren Baghdasaryan
2023-01-20 16:49             ` Matthew Wilcox
2023-01-20 17:08               ` Liam R. Howlett
2023-01-20 17:17                 ` Suren Baghdasaryan
2023-01-20 17:32                   ` Matthew Wilcox
2023-01-20 17:50                     ` Suren Baghdasaryan
2023-01-20 19:23                       ` Liam R. Howlett
2023-01-23  9:56                       ` Michal Hocko
2023-01-23 16:22                         ` Suren Baghdasaryan
2023-01-23 16:55                           ` Michal Hocko
2023-01-23 17:07                             ` Suren Baghdasaryan
2023-01-23 17:16                               ` Michal Hocko
2023-01-23 17:46                                 ` Suren Baghdasaryan
2023-01-23 18:23                                   ` Matthew Wilcox
2023-01-23 18:47                                     ` Suren Baghdasaryan
2023-01-23 19:18                                     ` Michal Hocko
2023-01-23 19:30                                       ` Matthew Wilcox
2023-01-23 19:57                                         ` Suren Baghdasaryan
2023-01-23 20:00                                         ` Michal Hocko
2023-01-23 20:08                                           ` Suren Baghdasaryan
2023-01-23 20:38                                           ` Liam R. Howlett
2023-01-20 17:21               ` Paul E. McKenney
2023-01-20 18:42                 ` Suren Baghdasaryan
2023-01-23  9:59           ` Michal Hocko
2023-01-23 17:43             ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 40/41] mm: separate vma->lock from vm_area_struct Suren Baghdasaryan
2023-01-17 18:33   ` Jann Horn
2023-01-17 19:01     ` Suren Baghdasaryan
2023-01-09 20:53 ` [PATCH 41/41] mm: replace rw_semaphore with atomic_t in vma_lock Suren Baghdasaryan
2023-01-10  8:04   ` Vlastimil Babka
2023-01-10 17:05     ` Suren Baghdasaryan
2023-01-16 11:14   ` Hyeonggon Yoo
2023-01-16 22:36     ` Suren Baghdasaryan
2023-01-17  4:14     ` Matthew Wilcox
2023-01-17  4:34       ` Suren Baghdasaryan
2023-01-17  5:46         ` Matthew Wilcox
2023-01-17  5:58           ` Suren Baghdasaryan
2023-01-17 18:23             ` Matthew Wilcox
2023-01-17 18:28               ` Suren Baghdasaryan
2023-01-17 20:31                 ` Michal Hocko
2023-01-17 21:00                   ` Suren Baghdasaryan
     [not found]   ` <20230116140649.2012-1-hdanton@sina.com>
2023-01-16 23:08     ` Suren Baghdasaryan
2023-01-16 23:11       ` Suren Baghdasaryan
     [not found]       ` <20230117031632.2321-1-hdanton@sina.com>
2023-01-17  4:52         ` Suren Baghdasaryan
     [not found]           ` <20230117083355.2374-1-hdanton@sina.com>
2023-01-17 18:21             ` Suren Baghdasaryan
2023-01-17 18:27               ` Matthew Wilcox
2023-01-17 18:31                 ` Suren Baghdasaryan
     [not found]                 ` <20230118062639.2839-1-hdanton@sina.com>
2023-01-18 18:35                   ` Matthew Wilcox
2023-01-17 18:11   ` Jann Horn
2023-01-17 18:26     ` Suren Baghdasaryan
2023-01-17 18:31       ` Matthew Wilcox
2023-01-17 18:36         ` Jann Horn
2023-01-17 18:49           ` Suren Baghdasaryan
2023-01-17 18:36         ` Suren Baghdasaryan
2023-01-17 18:48           ` Matthew Wilcox
2023-01-17 18:55             ` Suren Baghdasaryan
2023-01-17 18:59               ` Jann Horn
2023-01-17 19:06                 ` Suren Baghdasaryan

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