From: Jason Gunthorpe <jgg@nvidia.com>
To: Peter Xu <peterx@redhat.com>
Cc: David Hildenbrand <david@redhat.com>,
Lorenzo Stoakes <lstoakes@gmail.com>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
Andrew Morton <akpm@linux-foundation.org>,
Jens Axboe <axboe@kernel.dk>,
Matthew Wilcox <willy@infradead.org>,
Dennis Dalessandro <dennis.dalessandro@cornelisnetworks.com>,
Leon Romanovsky <leon@kernel.org>,
Christian Benvenuti <benve@cisco.com>,
Nelson Escobar <neescoba@cisco.com>,
Bernard Metzler <bmt@zurich.ibm.com>,
Peter Zijlstra <peterz@infradead.org>,
Ingo Molnar <mingo@redhat.com>,
Arnaldo Carvalho de Melo <acme@kernel.org>,
Mark Rutland <mark.rutland@arm.com>,
Alexander Shishkin <alexander.shishkin@linux.intel.com>,
Jiri Olsa <jolsa@kernel.org>, Namhyung Kim <namhyung@kernel.org>,
Ian Rogers <irogers@google.com>,
Adrian Hunter <adrian.hunter@intel.com>,
Bjorn Topel <bjorn@kernel.org>,
Magnus Karlsson <magnus.karlsson@intel.com>,
Maciej Fijalkowski <maciej.fijalkowski@intel.com>,
Jonathan Lemon <jonathan.lemon@gmail.com>,
"David S . Miller" <davem@davemloft.net>,
Eric Dumazet <edumazet@google.com>,
Jakub Kicinski <kuba@kernel.org>, Paolo Abeni <pabeni@redhat.com>,
Christian Brauner <brauner@kernel.org>,
Richard Cochran <richardcochran@gmail.com>,
Alexei Starovoitov <ast@kernel.org>,
Daniel Borkmann <daniel@iogearbox.net>,
Jesper Dangaard Brouer <hawk@kernel.org>,
John Fastabend <john.fastabend@gmail.com>,
linux-fsdevel@vger.kernel.org, linux-perf-users@vger.kernel.org,
netdev@vger.kernel.org, bpf@vger.kernel.org,
Oleg Nesterov <oleg@redhat.com>,
John Hubbard <jhubbard@nvidia.com>, Jan Kara <jack@suse.cz>,
"Kirill A . Shutemov" <kirill@shutemov.name>,
Pavel Begunkov <asml.silence@gmail.com>,
Mika Penttila <mpenttil@redhat.com>,
David Howells <dhowells@redhat.com>,
Christoph Hellwig <hch@lst.de>
Subject: Re: [PATCH v5] mm/gup: disallow GUP writing to file-backed mappings by default
Date: Fri, 28 Apr 2023 14:33:46 -0300 [thread overview]
Message-ID: <ZEwDelszXBRwUGS0@nvidia.com> (raw)
In-Reply-To: <ZEvsx998gDFig/zq@x1n>
On Fri, Apr 28, 2023 at 11:56:55AM -0400, Peter Xu wrote:
> > PageAnon(page) can be called from GUP-fast after grabbing a reference. See
> > gup_must_unshare().
>
> Hmm.. Is it a good idea at all to sacrifise all "!anon" fast-gups for this?
> People will silently got degrade even on legal pins on shmem/hugetlb, I
> think, which seems to be still a very major use case.
Remember gup fast was like this until quite recently - DAX wrecked it.
I fixed it when I changed DAX to not post-scan the VMA list..
I'm not sure longterm and really fast need to go together.
Jason
next prev parent reply other threads:[~2023-04-28 17:33 UTC|newest]
Thread overview: 53+ messages / expand[flat|nested] mbox.gz Atom feed top
2023-04-27 23:42 [PATCH v5] mm/gup: disallow GUP writing to file-backed mappings by default Lorenzo Stoakes
2023-04-28 2:06 ` John Hubbard
2023-04-28 4:21 ` Mika Penttilä
2023-04-28 11:51 ` Jan Kara
2023-04-28 11:59 ` Lorenzo Stoakes
2023-04-28 13:17 ` Jason Gunthorpe
2023-04-28 14:20 ` David Hildenbrand
2023-04-28 14:35 ` Jason Gunthorpe
2023-04-28 15:08 ` David Hildenbrand
2023-04-28 15:23 ` David Hildenbrand
2023-04-28 15:33 ` Lorenzo Stoakes
2023-04-28 15:34 ` David Hildenbrand
2023-04-28 15:43 ` David Hildenbrand
2023-04-28 16:09 ` Kirill A . Shutemov
2023-04-28 16:13 ` David Hildenbrand
2023-04-28 16:22 ` Kirill A . Shutemov
2023-04-28 16:39 ` Peter Xu
2023-04-28 16:51 ` David Hildenbrand
2023-04-28 16:56 ` Kirill A . Shutemov
2023-04-28 17:01 ` Lorenzo Stoakes
2023-04-28 17:02 ` David Hildenbrand
2023-04-28 17:31 ` Jason Gunthorpe
2023-04-28 17:42 ` Lorenzo Stoakes
2023-04-28 17:49 ` Jason Gunthorpe
2023-04-28 23:43 ` Kirill A . Shutemov
2023-05-02 8:00 ` Jan Kara
2023-05-02 8:39 ` Peter Zijlstra
2023-04-28 17:01 ` Lorenzo Stoakes
2023-04-28 17:05 ` David Hildenbrand
2023-04-28 17:13 ` Lorenzo Stoakes
2023-04-28 17:29 ` David Hildenbrand
2023-04-28 18:26 ` John Hubbard
2023-04-28 15:56 ` Peter Xu
2023-04-28 16:02 ` David Hildenbrand
2023-04-28 17:33 ` Jason Gunthorpe [this message]
2023-04-28 18:26 ` John Hubbard
2023-04-28 15:27 ` Jason Gunthorpe
2023-04-28 15:41 ` David Hildenbrand
2023-04-28 18:25 ` Theodore Ts'o
2023-04-28 18:50 ` Jason Gunthorpe
2023-04-29 4:21 ` Theodore Ts'o
2023-04-29 23:01 ` Jason Gunthorpe
2023-04-29 23:09 ` Lorenzo Stoakes
2023-05-01 7:27 ` Dave Chinner
2023-05-01 12:39 ` Jason Gunthorpe
2023-04-28 14:55 ` Lorenzo Stoakes
2023-04-28 15:13 ` David Hildenbrand
2023-04-28 15:15 ` Jens Axboe
2023-04-28 15:27 ` Lorenzo Stoakes
2023-04-28 15:24 ` Lorenzo Stoakes
2023-04-28 15:33 ` David Hildenbrand
2023-04-28 15:50 ` Lorenzo Stoakes
2023-04-28 16:00 ` David Hildenbrand
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