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From: "Kirill A. Shutemov" <kirill@shutemov.name>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Jerome Glisse <jglisse@redhat.com>,
	john.hubbard@gmail.com, Andrew Morton <akpm@linux-foundation.org>,
	linux-mm@kvack.org, Al Viro <viro@zeniv.linux.org.uk>,
	Christian Benvenuti <benve@cisco.com>,
	Christoph Hellwig <hch@infradead.org>,
	Christopher Lameter <cl@linux.com>,
	Dan Williams <dan.j.williams@intel.com>,
	Dave Chinner <david@fromorbit.com>,
	Dennis Dalessandro <dennis.dalessandro@intel.com>,
	Doug Ledford <dledford@redhat.com>,
	Ira Weiny <ira.weiny@intel.com>, Jan Kara <jack@suse.cz>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Matthew Wilcox <willy@infradead.org>,
	Michal Hocko <mhocko@kernel.org>,
	Mike Rapoport <rppt@linux.ibm.com>,
	Mike Marciniszyn <mike.marciniszyn@intel.com>,
	Ralph Campbell <rcampbell@nvidia.com>,
	Tom Talpey <tom@talpey.com>, LKML <linux-kernel@vger.kernel.org>,
	linux-fsdevel@vger.kernel.org
Subject: Re: [PATCH v4 1/1] mm: introduce put_user_page*(), placeholder versions
Date: Wed, 20 Mar 2019 12:40:29 +0300	[thread overview]
Message-ID: <20190320094029.ifweqx4wowyyr3wi@kshutemo-mobl1> (raw)
In-Reply-To: <bf443287-2461-ea2d-5a15-251190782ab7@nvidia.com>

On Tue, Mar 19, 2019 at 12:24:00PM -0700, John Hubbard wrote:
> So, I could be persuaded either way. But given the lack of an visible perf
> effects, and given that this could will get removed anyway because we'll
> likely end up with set_page_dirty() called at GUP time instead...it seems
> like it's probably OK to just leave it as is.

Apart from ugly code generated, other argument might be Spectre-like
attacks on these call. I would rather avoid indirect function calls
whenever possible. And I don't think opencodded versions of these
functions would look much worse.

-- 
 Kirill A. Shutemov

  reply	other threads:[~2019-03-20  9:40 UTC|newest]

Thread overview: 34+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2019-03-08 21:36 [PATCH v4 0/1] mm: introduce put_user_page*(), placeholder versions john.hubbard
2019-03-08 21:36 ` [PATCH v4 1/1] " john.hubbard
2019-03-19 12:04   ` Kirill A. Shutemov
2019-03-19 13:47     ` Jerome Glisse
2019-03-19 14:06       ` Kirill A. Shutemov
2019-03-19 14:15         ` Jerome Glisse
2019-03-19 20:01         ` John Hubbard
2019-03-20  9:28           ` Kirill A. Shutemov
2019-03-19 14:14       ` Jerome Glisse
2019-03-19 14:29         ` Kirill A. Shutemov
2019-03-19 15:36           ` Jan Kara
2019-03-19  9:03             ` Ira Weiny
2019-03-19 20:43               ` Tom Talpey
2019-03-19 20:45                 ` Jerome Glisse
2019-03-19 20:55                   ` Tom Talpey
2019-03-19 19:02             ` John Hubbard
2019-03-19 21:23         ` Dave Chinner
2019-03-19 22:06           ` Jerome Glisse
2019-03-19 23:57             ` Dave Chinner
2019-03-20  0:08               ` Jerome Glisse
2019-03-20  1:43                 ` John Hubbard
2019-03-20  4:33                   ` Jerome Glisse
2019-03-20  9:08                     ` Ira Weiny
2019-03-20 14:55                     ` William Kucharski
2019-03-20 14:59                       ` Jerome Glisse
2019-03-20  0:15               ` John Hubbard
2019-03-20  1:01               ` Christopher Lameter
2019-03-19 19:24       ` John Hubbard
2019-03-20  9:40         ` Kirill A. Shutemov [this message]
2019-03-08 23:21 ` [PATCH v4 0/1] " John Hubbard
2019-03-19 18:12 ` Christopher Lameter
2019-03-19 19:24   ` John Hubbard
2019-03-20  1:09     ` Christopher Lameter
2019-03-20  1:18       ` John Hubbard

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