From: Jason Gunthorpe <jgg@ziepe.ca>
To: David Hildenbrand <david@redhat.com>
Cc: Vlastimil Babka <vbabka@suse.cz>, Jens Axboe <axboe@kernel.dk>,
Andrew Dona-Couch <andrew@donacou.ch>,
Andrew Morton <akpm@linux-foundation.org>,
Drew DeVault <sir@cmpwn.com>,
Ammar Faizi <ammarfaizi2@gnuweeb.org>,
linux-kernel@vger.kernel.org, linux-api@vger.kernel.org,
io_uring Mailing List <io-uring@vger.kernel.org>,
Pavel Begunkov <asml.silence@gmail.com>,
linux-mm@kvack.org
Subject: Re: [PATCH] Increase default MLOCK_LIMIT to 8 MiB
Date: Wed, 24 Nov 2021 11:34:05 -0400 [thread overview]
Message-ID: <20211124153405.GJ5112@ziepe.ca> (raw)
In-Reply-To: <2cdbebb9-4c57-7839-71ab-166cae168c74@redhat.com>
On Wed, Nov 24, 2021 at 03:14:00PM +0100, David Hildenbrand wrote:
> I'm not aware of any where you can fragment 50% of all pageblocks in the
> system as an unprivileged user essentially consuming almost no memory
> and essentially staying inside well-defined memlock limits. But sure if
> there are "many" people will be able to come up with at least one
> comparable thing. I'll be happy to learn.
If the concern is that THP's can be DOS'd then any avenue that renders
the system out of THPs is a DOS attack vector. Including all the
normal workloads that people run and already complain that THPs get
exhausted.
A hostile userspace can only quicken this process.
> My position that FOLL_LONGTERM for unprivileged users is a strong no-go
> stands as it is.
As this basically excludes long standing pre-existing things like
RDMA, XDP, io_uring, and more I don't think this can be the general
answer for mm, sorry.
Sure, lets stop now since I don't think we can agree.
Jason
next prev parent reply other threads:[~2021-11-24 15:34 UTC|newest]
Thread overview: 58+ messages / expand[flat|nested] mbox.gz Atom feed top
2021-10-28 8:08 [PATCH] Increase default MLOCK_LIMIT to 8 MiB Drew DeVault
2021-10-28 18:22 ` Jens Axboe
2021-11-04 14:27 ` Cyril Hrubis
2021-11-04 14:44 ` Jens Axboe
2021-11-06 2:33 ` Ammar Faizi
2021-11-06 7:05 ` Drew DeVault
2021-11-06 7:12 ` Ammar Faizi
2021-11-16 4:35 ` Andrew Morton
2021-11-16 6:32 ` Drew DeVault
2021-11-16 19:47 ` Andrew Morton
2021-11-16 19:48 ` Drew DeVault
2021-11-16 21:37 ` Andrew Morton
2021-11-17 8:23 ` Drew DeVault
2021-11-22 17:11 ` David Hildenbrand
2021-11-22 17:55 ` Andrew Dona-Couch
2021-11-22 18:26 ` David Hildenbrand
2021-11-22 19:53 ` Jens Axboe
2021-11-22 20:03 ` Matthew Wilcox
2021-11-22 20:04 ` Jens Axboe
2021-11-22 20:08 ` David Hildenbrand
2021-11-22 20:44 ` Jens Axboe
2021-11-22 21:56 ` David Hildenbrand
2021-11-23 12:02 ` David Hildenbrand
2021-11-23 13:25 ` Jason Gunthorpe
2021-11-23 13:39 ` David Hildenbrand
2021-11-23 14:07 ` Jason Gunthorpe
2021-11-23 14:44 ` David Hildenbrand
2021-11-23 17:00 ` Jason Gunthorpe
2021-11-23 17:04 ` David Hildenbrand
2021-11-23 22:04 ` Vlastimil Babka
2021-11-23 23:59 ` Jason Gunthorpe
2021-11-24 8:57 ` David Hildenbrand
2021-11-24 13:23 ` Jason Gunthorpe
2021-11-24 13:25 ` David Hildenbrand
2021-11-24 13:28 ` Jason Gunthorpe
2021-11-24 13:29 ` David Hildenbrand
2021-11-24 13:48 ` Jason Gunthorpe
2021-11-24 14:14 ` David Hildenbrand
2021-11-24 15:34 ` Jason Gunthorpe [this message]
2021-11-24 16:43 ` David Hildenbrand
2021-11-24 18:35 ` Jason Gunthorpe
2021-11-24 19:09 ` David Hildenbrand
2021-11-24 23:11 ` Jason Gunthorpe
2021-11-30 15:52 ` David Hildenbrand
2021-11-24 18:37 ` David Hildenbrand
2021-11-24 14:37 ` Vlastimil Babka
2021-11-24 14:41 ` David Hildenbrand
2021-11-16 18:36 ` Matthew Wilcox
2021-11-16 18:44 ` Drew DeVault
2021-11-16 18:55 ` Jens Axboe
2021-11-16 19:21 ` Vito Caputo
2021-11-16 19:25 ` Drew DeVault
2021-11-16 19:46 ` Vito Caputo
2021-11-16 19:41 ` Jens Axboe
2021-11-17 22:26 ` Johannes Weiner
2021-11-17 23:17 ` Jens Axboe
2021-11-18 21:58 ` Andrew Morton
2021-11-19 7:41 ` Drew DeVault
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