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From: John Hubbard <jhubbard@nvidia.com>
To: Michel Lespinasse <walken@google.com>
Cc: Matthew Wilcox <willy@infradead.org>,
	Laurent Dufour <ldufour@linux.ibm.com>,
	Andrew Morton <akpm@linux-foundation.org>,
	linux-mm <linux-mm@kvack.org>,
	LKML <linux-kernel@vger.kernel.org>,
	Peter Zijlstra <peterz@infradead.org>,
	Vlastimil Babka <vbabka@suse.cz>,
	Liam Howlett <Liam.Howlett@oracle.com>,
	Jerome Glisse <jglisse@redhat.com>,
	Davidlohr Bueso <dave@stgolabs.net>,
	David Rientjes <rientjes@google.com>,
	Hugh Dickins <hughd@google.com>, Ying Han <yinghan@google.com>,
	Jason Gunthorpe <jgg@ziepe.ca>,
	Daniel Jordan <daniel.m.jordan@oracle.com>
Subject: Re: [PATCH v5.5 10/10] mmap locking API: rename mmap_sem to mmap_lock
Date: Wed, 20 May 2020 00:32:53 -0700	[thread overview]
Message-ID: <9c45327f-5542-c033-ec5e-201e9b0583aa@nvidia.com> (raw)
In-Reply-To: <CANN689EubtJL2mbcz5Au05nW87gVuY-19r7nZd9x0y320PUb0g@mail.gmail.com>

On 2020-05-19 19:39, Michel Lespinasse wrote:
...
>> That gives you additional options inside internal_get_user_pages_fast(), such
>> as, approximately:
>>
>> if (!(gup_flags & FOLL_FAST_ONLY))
>>          might_lock_read(&current->mm->mmap_lock);
>>
>> ...not that that is necessarily a great idea, seeing as how it merely changes
>> "might lock" into "maybe might lock".  :)
> 
> I think that is completely fine, makes sure everyone not using
> FOLL_FAST_ONLY realizes that the call could block.
> 
> Can I ask you to add that assertion in your patchset ? Based on
> Matthew's feedback, I would do it in my patchset, but it doesn't seem
> worth doing if we know this will conflict with your changes.
> 

Sure, that's no problem. Although it looks like my changes may land
in mmotm first, and then your patchset, so maybe the right move is to
make this change *after* both of those things happen, yes?


thanks,
-- 
John Hubbard
NVIDIA


  reply	other threads:[~2020-05-20  7:32 UTC|newest]

Thread overview: 50+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-04-22  0:14 [PATCH v5 00/10] Add a new mmap locking API wrapping mmap_sem calls Michel Lespinasse
2020-04-22  0:14 ` [PATCH v5 01/10] mmap locking API: initial implementation as rwsem wrappers Michel Lespinasse
2020-05-18  9:28   ` Vlastimil Babka
2020-05-18 13:18   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 02/10] MMU notifier: use the new mmap locking API Michel Lespinasse
2020-05-18  9:28   ` Vlastimil Babka
2020-05-18 13:19   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 03/10] DMA reservations: " Michel Lespinasse
2020-05-18  9:30   ` Vlastimil Babka
2020-05-18 13:20   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 04/10] mmap locking API: use coccinelle to convert mmap_sem rwsem call sites Michel Lespinasse
2020-05-18  9:36   ` Vlastimil Babka
2020-05-18 13:21   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 05/10] mmap locking API: convert mmap_sem call sites missed by coccinelle Michel Lespinasse
2020-05-18  9:44   ` Vlastimil Babka
2020-05-18 13:23   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 06/10] mmap locking API: convert nested write lock sites Michel Lespinasse
2020-05-18 10:32   ` Vlastimil Babka
2020-05-19 12:54     ` Michel Lespinasse
2020-05-18 13:24   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 07/10] mmap locking API: add mmap_read_trylock_non_owner() Michel Lespinasse
2020-05-18 10:42   ` Vlastimil Babka
2020-04-22  0:14 ` [PATCH v5 08/10] mmap locking API: add MMAP_LOCK_INITIALIZER Michel Lespinasse
2020-05-18 10:45   ` Vlastimil Babka
2020-05-19 12:56     ` Michel Lespinasse
2020-05-18 13:33   ` Laurent Dufour
2020-04-22  0:14 ` [PATCH v5 09/10] mmap locking API: add mmap_assert_locked Michel Lespinasse
2020-04-22  2:10   ` Michel Lespinasse
2020-04-22  2:18     ` Matthew Wilcox
2020-04-24  1:44       ` Michel Lespinasse
2020-04-22  0:14 ` [PATCH v5 10/10] mmap locking API: rename mmap_sem to mmap_lock Michel Lespinasse
2020-04-22  1:58   ` Matthew Wilcox
2020-04-22 22:54     ` Michel Lespinasse
2020-04-23  1:59       ` Matthew Wilcox
2020-04-24  1:26         ` Michel Lespinasse
2020-04-24  1:38           ` [PATCH v5.5 09/10] mmap locking API: add mmap_assert_locked() and mmap_assert_write_locked() Michel Lespinasse
2020-05-18 11:01             ` Vlastimil Babka
2020-05-19 13:06               ` Michel Lespinasse
2020-04-24  1:39           ` [PATCH v5.5 10/10] mmap locking API: rename mmap_sem to mmap_lock Michel Lespinasse
2020-05-18 11:07             ` Vlastimil Babka
2020-05-19 13:12               ` Michel Lespinasse
2020-05-18 13:45             ` Laurent Dufour
2020-05-19 13:10               ` Michel Lespinasse
2020-05-19 13:20                 ` Laurent Dufour
2020-05-19 15:32                   ` Matthew Wilcox
2020-05-19 18:14                     ` John Hubbard
2020-05-20  2:39                       ` Michel Lespinasse
2020-05-20  7:32                         ` John Hubbard [this message]
2020-05-20  8:02                           ` Michel Lespinasse
2020-05-20 12:48                         ` Jason Gunthorpe

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