From: Linus Torvalds <torvalds@linux-foundation.org>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>,
Linux-MM <linux-mm@kvack.org>,
Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
Yu Zhao <yuzhao@google.com>, Andy Lutomirski <luto@kernel.org>,
Peter Xu <peterx@redhat.com>, Pavel Emelyanov <xemul@openvz.org>,
Mike Kravetz <mike.kravetz@oracle.com>,
Mike Rapoport <rppt@linux.vnet.ibm.com>,
Minchan Kim <minchan@kernel.org>, Will Deacon <will@kernel.org>,
Peter Zijlstra <peterz@infradead.org>,
Hugh Dickins <hughd@google.com>,
"Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>,
Matthew Wilcox <willy@infradead.org>,
Oleg Nesterov <oleg@redhat.com>, Jann Horn <jannh@google.com>,
Kees Cook <keescook@chromium.org>,
Leon Romanovsky <leonro@nvidia.com>,
Jason Gunthorpe <jgg@ziepe.ca>, Jan Kara <jack@suse.cz>,
Kirill Tkhai <ktkhai@virtuozzo.com>
Subject: Re: [PATCH 2/2] mm: soft_dirty: userfaultfd: introduce wrprotect_tlb_flush_pending
Date: Thu, 7 Jan 2021 14:20:27 -0800 [thread overview]
Message-ID: <CAHk-=wi691+mXC4NCXZ_f1+kf_YAB9WBM-LqhrX8=eSmYM=WFw@mail.gmail.com> (raw)
In-Reply-To: <394e17bc-8bed-4d17-5dba-9ab8052c8bea@nvidia.com>
On Thu, Jan 7, 2021 at 2:14 PM John Hubbard <jhubbard@nvidia.com> wrote:
> >
> > Literally just adding a " && page_mapcount(page) == 1" in there
> > (probably best done inside page_maybe_dma_pinned() itself)
>
> Well, that means that pages that are used for pinned DMA like this, can
> not be shared with other processes. Is that an acceptable limitation
> for the RDMA users? It seems a bit constraining, at first glance anyway.
Hmm, add a check for the page being PageAnon(), perhaps?
If it's a shared vma, then the page can be pinned shared with multiple
mappings, I agree.
So yeah, I didn't think it through entirely.. And maybe I'm still
missing something else..
Linus
next prev parent reply other threads:[~2021-01-07 22:21 UTC|newest]
Thread overview: 119+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-12-25 9:25 [RFC PATCH v2 0/2] mm: fix races due to deferred TLB flushes Nadav Amit
2020-12-25 9:25 ` [RFC PATCH v2 1/2] mm/userfaultfd: fix memory corruption due to writeprotect Nadav Amit
2021-01-04 12:22 ` Peter Zijlstra
2021-01-04 19:24 ` Andrea Arcangeli
2021-01-04 19:35 ` Nadav Amit
2021-01-04 20:19 ` Andrea Arcangeli
2021-01-04 20:39 ` Nadav Amit
2021-01-04 21:01 ` Andrea Arcangeli
2021-01-04 21:26 ` Nadav Amit
2021-01-05 18:45 ` Andrea Arcangeli
2021-01-05 19:05 ` Nadav Amit
2021-01-05 19:45 ` Andrea Arcangeli
2021-01-05 20:06 ` Nadav Amit
2021-01-05 21:06 ` Andrea Arcangeli
2021-01-05 21:43 ` Peter Xu
2021-01-05 8:13 ` Peter Zijlstra
2021-01-05 8:52 ` Nadav Amit
2021-01-05 14:26 ` Peter Zijlstra
2021-01-05 8:58 ` Peter Zijlstra
2021-01-05 9:22 ` Nadav Amit
2021-01-05 17:58 ` Andrea Arcangeli
2021-01-05 15:08 ` Peter Xu
2021-01-05 18:08 ` Andrea Arcangeli
2021-01-05 18:41 ` Peter Xu
2021-01-05 18:55 ` Andrea Arcangeli
2021-01-05 19:07 ` Nadav Amit
2021-01-05 19:43 ` Peter Xu
2020-12-25 9:25 ` [RFC PATCH v2 2/2] fs/task_mmu: acquire mmap_lock for write on soft-dirty cleanup Nadav Amit
2021-01-05 15:08 ` Will Deacon
2021-01-05 18:20 ` Andrea Arcangeli
2021-01-05 19:26 ` Nadav Amit
2021-01-05 20:39 ` Andrea Arcangeli
2021-01-05 21:20 ` Yu Zhao
2021-01-05 21:22 ` Nadav Amit
2021-01-05 22:16 ` Will Deacon
2021-01-06 0:29 ` Andrea Arcangeli
2021-01-06 0:02 ` Andrea Arcangeli
2021-01-07 20:04 ` [PATCH 0/2] page_count can't be used to decide when wp_page_copy Andrea Arcangeli
2021-01-07 20:04 ` [PATCH 1/2] mm: proc: Invalidate TLB after clearing soft-dirty page state Andrea Arcangeli
2021-01-07 20:04 ` [PATCH 2/2] mm: soft_dirty: userfaultfd: introduce wrprotect_tlb_flush_pending Andrea Arcangeli
2021-01-07 20:17 ` Linus Torvalds
2021-01-07 20:17 ` Linus Torvalds
2021-01-07 20:25 ` Linus Torvalds
2021-01-07 20:25 ` Linus Torvalds
2021-01-07 20:58 ` Andrea Arcangeli
2021-01-07 21:29 ` Linus Torvalds
2021-01-07 21:29 ` Linus Torvalds
2021-01-07 21:53 ` John Hubbard
2021-01-07 22:00 ` Linus Torvalds
2021-01-07 22:00 ` Linus Torvalds
2021-01-07 22:14 ` John Hubbard
2021-01-07 22:20 ` Linus Torvalds [this message]
2021-01-07 22:20 ` Linus Torvalds
2021-01-07 22:24 ` Linus Torvalds
2021-01-07 22:24 ` Linus Torvalds
2021-01-07 22:37 ` John Hubbard
2021-01-15 11:27 ` Jan Kara
2021-01-07 22:31 ` Andrea Arcangeli
2021-01-07 22:42 ` Linus Torvalds
2021-01-07 22:42 ` Linus Torvalds
2021-01-07 22:51 ` Linus Torvalds
2021-01-07 22:51 ` Linus Torvalds
2021-01-07 23:48 ` Andrea Arcangeli
2021-01-08 0:25 ` Linus Torvalds
2021-01-08 0:25 ` Linus Torvalds
2021-01-08 12:48 ` Will Deacon
2021-01-08 16:14 ` Andrea Arcangeli
2021-01-08 17:39 ` Linus Torvalds
2021-01-08 17:39 ` Linus Torvalds
2021-01-08 17:53 ` Andrea Arcangeli
2021-01-08 19:25 ` Linus Torvalds
2021-01-08 19:25 ` Linus Torvalds
2021-01-09 0:12 ` Andrea Arcangeli
2021-01-08 17:30 ` Linus Torvalds
2021-01-08 17:30 ` Linus Torvalds
2021-01-07 23:28 ` Andrea Arcangeli
2021-01-07 21:36 ` kernel test robot
2021-01-07 21:36 ` kernel test robot
2021-01-07 20:25 ` [PATCH 0/2] page_count can't be used to decide when wp_page_copy Jason Gunthorpe
2021-01-07 20:32 ` Linus Torvalds
2021-01-07 20:32 ` Linus Torvalds
2021-01-07 21:05 ` Linus Torvalds
2021-01-07 21:05 ` Linus Torvalds
2021-01-07 22:02 ` Andrea Arcangeli
2021-01-07 22:17 ` Linus Torvalds
2021-01-07 22:17 ` Linus Torvalds
2021-01-07 22:56 ` Andrea Arcangeli
2021-01-09 19:32 ` Matthew Wilcox
2021-01-09 19:46 ` Linus Torvalds
2021-01-09 19:46 ` Linus Torvalds
2021-01-15 14:30 ` Jan Kara
2021-01-07 21:54 ` Andrea Arcangeli
2021-01-07 21:45 ` Andrea Arcangeli
2021-01-08 13:36 ` Jason Gunthorpe
2021-01-08 17:00 ` Andrea Arcangeli
2021-01-08 18:19 ` Jason Gunthorpe
2021-01-08 18:31 ` Andy Lutomirski
2021-01-08 18:31 ` Andy Lutomirski
2021-01-08 18:38 ` Linus Torvalds
2021-01-08 18:38 ` Linus Torvalds
2021-01-08 23:34 ` Andrea Arcangeli
2021-01-09 19:03 ` Andy Lutomirski
2021-01-09 19:03 ` Andy Lutomirski
2021-01-09 19:15 ` Linus Torvalds
2021-01-09 19:15 ` Linus Torvalds
2021-01-08 18:59 ` Linus Torvalds
2021-01-08 18:59 ` Linus Torvalds
2021-01-08 22:43 ` Andrea Arcangeli
2021-01-09 0:42 ` Jason Gunthorpe
2021-01-09 2:50 ` Andrea Arcangeli
2021-01-11 14:30 ` Jason Gunthorpe
2021-01-13 21:56 ` Jerome Glisse
2021-01-13 23:39 ` Jason Gunthorpe
2021-01-14 2:35 ` Jerome Glisse
2021-01-09 3:49 ` Hillf Danton
2021-01-11 14:39 ` Jason Gunthorpe
2021-01-05 21:55 ` [RFC PATCH v2 2/2] fs/task_mmu: acquire mmap_lock for write on soft-dirty cleanup Peter Xu
2021-03-02 22:13 ` [RFC PATCH v2 0/2] mm: fix races due to deferred TLB flushes Peter Xu
2021-03-02 22:14 ` Nadav Amit
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