From: Mike Rapoport <rppt@kernel.org>
To: Suren Baghdasaryan <surenb@google.com>
Cc: akpm@linux-foundation.org, michel@lespinasse.org,
jglisse@google.com, mhocko@suse.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, paulmck@kernel.org,
mingo@redhat.com, will@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, 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 v4 2/7] mm: introduce vma->vm_flags wrapper functions
Date: Thu, 26 Jan 2023 21:42:05 +0200 [thread overview]
Message-ID: <Y9LXjSKIb27YUk0d@kernel.org> (raw)
In-Reply-To: <20230126193752.297968-3-surenb@google.com>
On Thu, Jan 26, 2023 at 11:37:47AM -0800, Suren Baghdasaryan wrote:
> vm_flags are among VMA attributes which affect decisions like VMA merging
> and splitting. Therefore all vm_flags modifications are performed after
> taking exclusive mmap_lock to prevent vm_flags updates racing with such
> operations. Introduce modifier functions for vm_flags to be used whenever
> flags are updated. This way we can better check and control correct
> locking behavior during these updates.
>
> Signed-off-by: Suren Baghdasaryan <surenb@google.com>
> Reviewed-by: Davidlohr Bueso <dave@stgolabs.net>
> Acked-by: Michal Hocko <mhocko@suse.com>
> Acked-by: Mel Gorman <mgorman@techsingularity.net>
Acked-by: Mike Rapoport (IBM) <rppt@kernel.org>
> ---
> include/linux/mm.h | 40 ++++++++++++++++++++++++++++++++++++++++
> include/linux/mm_types.h | 10 +++++++++-
> 2 files changed, 49 insertions(+), 1 deletion(-)
>
> diff --git a/include/linux/mm.h b/include/linux/mm.h
> index 8d636e895ee9..abb31103d060 100644
> --- a/include/linux/mm.h
> +++ b/include/linux/mm.h
> @@ -627,6 +627,46 @@ static inline void vma_init(struct vm_area_struct *vma, struct mm_struct *mm)
> INIT_LIST_HEAD(&vma->anon_vma_chain);
> }
>
> +/* Use when VMA is not part of the VMA tree and needs no locking */
> +static inline void vm_flags_init(struct vm_area_struct *vma,
> + vm_flags_t flags)
> +{
> + ACCESS_PRIVATE(vma, __vm_flags) = flags;
> +}
> +
> +/* Use when VMA is part of the VMA tree and modifications need coordination */
> +static inline void vm_flags_reset(struct vm_area_struct *vma,
> + vm_flags_t flags)
> +{
> + mmap_assert_write_locked(vma->vm_mm);
> + vm_flags_init(vma, flags);
> +}
> +
> +static inline void vm_flags_set(struct vm_area_struct *vma,
> + vm_flags_t flags)
> +{
> + mmap_assert_write_locked(vma->vm_mm);
> + ACCESS_PRIVATE(vma, __vm_flags) |= flags;
> +}
> +
> +static inline void vm_flags_clear(struct vm_area_struct *vma,
> + vm_flags_t flags)
> +{
> + mmap_assert_write_locked(vma->vm_mm);
> + ACCESS_PRIVATE(vma, __vm_flags) &= ~flags;
> +}
> +
> +/*
> + * Use only when the order of set/clear operations is unimportant, otherwise
> + * use vm_flags_{set|clear} explicitly.
> + */
> +static inline void vm_flags_mod(struct vm_area_struct *vma,
> + vm_flags_t set, vm_flags_t clear)
> +{
> + mmap_assert_write_locked(vma->vm_mm);
> + vm_flags_init(vma, (vma->vm_flags | set) & ~clear);
> +}
> +
> static inline void vma_set_anonymous(struct vm_area_struct *vma)
> {
> vma->vm_ops = NULL;
> diff --git a/include/linux/mm_types.h b/include/linux/mm_types.h
> index 2d6d790d9bed..da983aedb741 100644
> --- a/include/linux/mm_types.h
> +++ b/include/linux/mm_types.h
> @@ -491,7 +491,15 @@ struct vm_area_struct {
> * See vmf_insert_mixed_prot() for discussion.
> */
> pgprot_t vm_page_prot;
> - unsigned long vm_flags; /* Flags, see mm.h. */
> +
> + /*
> + * Flags, see mm.h.
> + * To modify use vm_flags_{init|reset|set|clear|mod} functions.
> + */
> + union {
> + const vm_flags_t vm_flags;
> + vm_flags_t __private __vm_flags;
> + };
>
> /*
> * For areas with an address space and backing store,
> --
> 2.39.1
>
--
Sincerely yours,
Mike.
next prev parent reply other threads:[~2023-01-26 19:42 UTC|newest]
Thread overview: 29+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-01-26 19:37 [PATCH v4 0/7] introduce vm_flags modifier functions Suren Baghdasaryan
2023-01-26 19:37 ` [PATCH v4 1/7] kernel/fork: convert vma assignment to a memcpy Suren Baghdasaryan
2023-01-26 19:40 ` Mike Rapoport
2023-01-26 19:37 ` [PATCH v4 2/7] mm: introduce vma->vm_flags wrapper functions Suren Baghdasaryan
2023-01-26 19:42 ` Mike Rapoport [this message]
2023-02-08 1:48 ` Hyeonggon Yoo
2023-01-26 19:37 ` [PATCH v4 3/7] mm: replace VM_LOCKED_CLEAR_MASK with VM_LOCKED_MASK Suren Baghdasaryan
2023-01-27 17:45 ` Davidlohr Bueso
2023-01-27 20:56 ` Suren Baghdasaryan
2023-01-26 19:37 ` [PATCH v4 4/7] mm: replace vma->vm_flags direct modifications with modifier calls Suren Baghdasaryan
2023-01-27 14:23 ` Liam R. Howlett
2023-01-31 8:32 ` Hyeonggon Yoo
2023-01-31 18:54 ` Suren Baghdasaryan
2023-01-31 20:53 ` Andrew Morton
2023-01-31 21:08 ` Suren Baghdasaryan
2023-01-31 23:12 ` Andrew Morton
2023-02-01 0:03 ` Suren Baghdasaryan
2023-02-01 12:23 ` Hyeonggon Yoo
2023-01-26 19:37 ` [PATCH v4 5/7] mm: replace vma->vm_flags indirect modification in ksm_madvise Suren Baghdasaryan
2023-01-26 22:45 ` Michael Ellerman
2023-02-08 1:54 ` Hyeonggon Yoo
2023-01-26 19:37 ` [PATCH v4 6/7] mm: introduce __vm_flags_mod and use it in untrack_pfn Suren Baghdasaryan
2023-01-26 19:44 ` Mike Rapoport
2023-01-26 19:37 ` [PATCH v4 7/7] mm: export dump_mm() Suren Baghdasaryan
2023-03-14 20:11 ` [PATCH v4 0/7] introduce vm_flags modifier functions Alex Williamson
2023-03-17 19:08 ` Suren Baghdasaryan
2023-03-17 22:40 ` Alex Williamson
2023-03-17 23:04 ` Suren Baghdasaryan
2023-03-22 13:48 ` Jason Gunthorpe
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