From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, michel@lespinasse.org,
jglisse@google.com, mhocko@suse.com, vbabka@suse.cz,
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Subject: Re: [PATCH v4 24/33] mm: fall back to mmap_lock if vma->anon_vma is not yet set
Date: Wed, 1 Mar 2023 09:54:21 +0000 [thread overview]
Message-ID: <Y/8gzRg3voRhNOsM@localhost> (raw)
In-Reply-To: <20230227173632.3292573-25-surenb@google.com>
On Mon, Feb 27, 2023 at 09:36:23AM -0800, Suren Baghdasaryan wrote:
> When vma->anon_vma is not set, page fault handler will set it by either
> reusing anon_vma of an adjacent VMA if VMAs are compatible or by
> allocating a new one. find_mergeable_anon_vma() walks VMA tree to find
> a compatible adjacent VMA and that requires not only the faulting VMA
> to be stable but also the tree structure and other VMAs inside that tree.
> Therefore locking just the faulting VMA is not enough for this search.
> Fall back to taking mmap_lock when vma->anon_vma is not set. This
> situation happens only on the first page fault and should not affect
> overall performance.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> ---
> mm/memory.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index bda4c1a991f0..8855846a361b 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -5243,6 +5243,10 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm,
> if (!vma_is_anonymous(vma))
> goto inval;
>
> + /* find_mergeable_anon_vma uses adjacent vmas which are not locked */
> + if (!vma->anon_vma)
> + goto inval;
> +
> if (!vma_start_read(vma))
> goto inval;
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> --
> 2.39.2.722.g9855ee24e9-goog
>
>
WARNING: multiple messages have this Message-ID (diff)
From: Hyeonggon Yoo <42.hyeyoo@gmail.com>
To: Suren Baghdasaryan <surenb@google.com>
Cc: michel@lespinasse.org, joelaf@google.com, songliubraving@fb.com,
mhocko@suse.com, leewalsh@google.com, david@redhat.com,
peterz@infradead.org, bigeasy@linutronix.de, peterx@redhat.com,
dhowells@redhat.com, linux-mm@kvack.org, edumazet@google.com,
jglisse@google.com, punit.agrawal@bytedance.com, will@kernel.org,
arjunroy@google.com, chriscli@google.com, dave@stgolabs.net,
minchan@google.com, x86@kernel.org, hughd@google.com,
willy@infradead.org, gurua@google.com, mingo@redhat.com,
linux-arm-kernel@lists.infradead.org, rientjes@google.com,
axelrasmussen@google.com, kernel-team@android.com,
michalechner92@googlemail.com, soheil@google.com,
paulmck@kernel.org, jannh@google.com, liam.howlett@oracle.com,
shakeelb@google.com, luto@kernel.org, gthelen@google.com,
ldufour@linux.ibm.com, vbabka@suse.cz, posk@google.com,
lstoakes@gmail.com, peterjung1337@gmail.com,
linuxppc-dev@lists.ozlabs.org, kent.overstreet@linux.dev,
linux-kernel@vger.kernel.org, hannes@cmpxchg.org,
akpm@linux-foundati on.org, tatashin@google.com,
mgorman@techsingularity.net, rppt@kernel.org
Subject: Re: [PATCH v4 24/33] mm: fall back to mmap_lock if vma->anon_vma is not yet set
Date: Wed, 1 Mar 2023 09:54:21 +0000 [thread overview]
Message-ID: <Y/8gzRg3voRhNOsM@localhost> (raw)
In-Reply-To: <20230227173632.3292573-25-surenb@google.com>
On Mon, Feb 27, 2023 at 09:36:23AM -0800, Suren Baghdasaryan wrote:
> When vma->anon_vma is not set, page fault handler will set it by either
> reusing anon_vma of an adjacent VMA if VMAs are compatible or by
> allocating a new one. find_mergeable_anon_vma() walks VMA tree to find
> a compatible adjacent VMA and that requires not only the faulting VMA
> to be stable but also the tree structure and other VMAs inside that tree.
> Therefore locking just the faulting VMA is not enough for this search.
> Fall back to taking mmap_lock when vma->anon_vma is not set. This
> situation happens only on the first page fault and should not affect
> overall performance.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> ---
> mm/memory.c | 4 ++++
> 1 file changed, 4 insertions(+)
>
> diff --git a/mm/memory.c b/mm/memory.c
> index bda4c1a991f0..8855846a361b 100644
> --- a/mm/memory.c
> +++ b/mm/memory.c
> @@ -5243,6 +5243,10 @@ struct vm_area_struct *lock_vma_under_rcu(struct mm_struct *mm,
> if (!vma_is_anonymous(vma))
> goto inval;
>
> + /* find_mergeable_anon_vma uses adjacent vmas which are not locked */
> + if (!vma->anon_vma)
> + goto inval;
> +
> if (!vma_start_read(vma))
> goto inval;
Reviewed-by: Hyeonggon Yoo <42.hyeyoo@gmail.com>
> --
> 2.39.2.722.g9855ee24e9-goog
>
>
next prev parent reply other threads:[~2023-03-01 9:54 UTC|newest]
Thread overview: 134+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-02-27 17:35 [PATCH v4 00/33] Per-VMA locks Suren Baghdasaryan
2023-02-27 17:35 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 01/33] maple_tree: Be more cautious about dead nodes Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 02/33] maple_tree: Detect dead nodes in mas_start() Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 03/33] maple_tree: Fix freeing of nodes in rcu mode Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 04/33] maple_tree: remove extra smp_wmb() from mas_dead_leaves() Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 05/33] maple_tree: Fix write memory barrier of nodes once dead for RCU mode Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 06/33] maple_tree: Add smp_rmb() to dead node detection Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 07/33] maple_tree: Add RCU lock checking to rcu callback functions Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 08/33] mm: Enable maple tree RCU mode by default Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 09/33] mm: introduce CONFIG_PER_VMA_LOCK Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 10/33] mm: rcu safe VMA freeing Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 11/33] mm: move mmap_lock assert function definitions Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 12/33] mm: add per-VMA lock and helper functions to control it Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 13/33] mm: mark VMA as being written when changing vm_flags Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 14/33] mm/mmap: move vma_prepare before vma_adjust_trans_huge Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 15/33] mm/khugepaged: write-lock VMA while collapsing a huge page Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 16/33] mm/mmap: write-lock VMAs in vma_prepare before modifying them Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 17/33] mm/mremap: write-lock VMA while remapping it to a new address range Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-03-01 7:01 ` Hyeonggon Yoo
2023-03-01 7:01 ` Hyeonggon Yoo
2023-02-27 17:36 ` [PATCH v4 18/33] mm: write-lock VMAs before removing them from VMA tree Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-03-01 7:43 ` Hyeonggon Yoo
2023-03-01 7:43 ` Hyeonggon Yoo
2023-03-01 7:56 ` Hyeonggon Yoo
2023-03-01 7:56 ` Hyeonggon Yoo
2023-03-01 18:34 ` Suren Baghdasaryan
2023-03-01 18:34 ` Suren Baghdasaryan
2023-03-01 18:42 ` Suren Baghdasaryan
2023-03-01 18:42 ` Suren Baghdasaryan
2023-03-02 0:53 ` Hyeonggon Yoo
2023-03-02 0:53 ` Hyeonggon Yoo
2023-03-02 2:21 ` Suren Baghdasaryan
2023-03-02 2:21 ` Suren Baghdasaryan
2023-03-01 19:07 ` Suren Baghdasaryan
2023-03-01 19:07 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 19/33] mm: conditionally write-lock VMA in free_pgtables Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 20/33] kernel/fork: assert no VMA readers during its destruction Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 21/33] mm/mmap: prevent pagefault handler from racing with mmu_notifier registration Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 22/33] mm: introduce vma detached flag Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 23/33] mm: introduce lock_vma_under_rcu to be used from arch-specific code Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 24/33] mm: fall back to mmap_lock if vma->anon_vma is not yet set Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-03-01 9:54 ` Hyeonggon Yoo [this message]
2023-03-01 9:54 ` Hyeonggon Yoo
2023-02-27 17:36 ` [PATCH v4 25/33] mm: add FAULT_FLAG_VMA_LOCK flag Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 26/33] mm: prevent do_swap_page from handling page faults under VMA lock Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 27/33] mm: prevent userfaults to be handled under per-vma lock Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 28/33] mm: introduce per-VMA lock statistics Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 29/33] x86/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-06-29 14:40 ` Jiri Slaby
2023-06-29 14:40 ` Jiri Slaby
2023-06-29 15:30 ` Suren Baghdasaryan
2023-06-29 15:30 ` Suren Baghdasaryan
2023-06-30 6:35 ` Jiri Slaby
2023-06-30 6:35 ` Jiri Slaby
2023-06-30 8:28 ` Jiri Slaby
2023-06-30 8:28 ` Jiri Slaby
2023-06-30 8:43 ` Jiri Slaby
2023-06-30 8:43 ` Jiri Slaby
2023-06-30 17:40 ` Suren Baghdasaryan
2023-06-30 17:40 ` Suren Baghdasaryan
2023-07-03 10:47 ` Jiri Slaby
2023-07-03 10:47 ` Jiri Slaby
2023-07-03 13:52 ` Holger Hoffstätte
2023-07-03 14:45 ` Suren Baghdasaryan
2023-07-03 15:24 ` Suren Baghdasaryan
2023-07-03 18:28 ` Suren Baghdasaryan
2023-07-05 22:15 ` Suren Baghdasaryan
2023-07-05 22:37 ` Holger Hoffstätte
2023-07-05 22:55 ` Suren Baghdasaryan
2023-07-06 14:27 ` Holger Hoffstätte
2023-07-06 16:11 ` Suren Baghdasaryan
2023-07-07 2:23 ` Suren Baghdasaryan
2023-07-07 4:40 ` Suren Baghdasaryan
2023-07-11 6:20 ` Jiri Slaby
2023-06-29 17:06 ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-06-29 17:06 ` Linux regression tracking #adding (Thorsten Leemhuis)
2023-07-10 10:45 ` Linux regression tracking #update (Thorsten Leemhuis)
2023-07-03 9:58 ` Linux regression tracking (Thorsten Leemhuis)
2023-07-03 9:58 ` Linux regression tracking (Thorsten Leemhuis)
2023-02-27 17:36 ` [PATCH v4 30/33] arm64/mm: " Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 31/33] powerc/mm: " Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-03-06 15:42 ` [PATCH] powerpc/mm: fix mmap_lock bad unlock Laurent Dufour
2023-03-06 15:42 ` Laurent Dufour
2023-03-06 20:25 ` [PATCH v4 31/33] powerc/mm: try VMA lock-based page fault handling first Suren Baghdasaryan
2023-03-06 20:25 ` Suren Baghdasaryan
2023-03-06 20:25 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 32/33] mm/mmap: free vm_area_struct without call_rcu in exit_mmap Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-02-27 17:36 ` [PATCH v4 33/33] mm: separate vma->lock from vm_area_struct Suren Baghdasaryan
2023-02-27 17:36 ` Suren Baghdasaryan
2023-07-11 10:35 ` [PATCH v4 00/33] Per-VMA locks Leon Romanovsky
2023-07-11 10:35 ` Leon Romanovsky
2023-07-11 10:39 ` Vlastimil Babka
2023-07-11 10:39 ` Vlastimil Babka
2023-07-11 11:01 ` Leon Romanovsky
2023-07-11 11:01 ` Leon Romanovsky
2023-07-11 11:09 ` Leon Romanovsky
2023-07-11 11:09 ` Leon Romanovsky
2023-07-11 16:35 ` Suren Baghdasaryan
2023-07-11 16:35 ` Suren Baghdasaryan
2023-07-11 17:14 ` Leon Romanovsky
2023-07-11 17:14 ` Leon Romanovsky
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