From: Michel Lespinasse <walken@google.com>
To: Peter Zijlstra <peterz@infradead.org>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm <linux-mm@kvack.org>,
LKML <linux-kernel@vger.kernel.org>,
Laurent Dufour <ldufour@linux.ibm.com>,
Vlastimil Babka <vbabka@suse.cz>,
Matthew Wilcox <willy@infradead.org>,
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>,
Markus Elfring <Markus.Elfring@web.de>
Subject: Re: [PATCH v3 06/10] mmap locking API: convert nested write lock sites
Date: Mon, 6 Apr 2020 08:35:03 -0700 [thread overview]
Message-ID: <CANN689H1VjW4aC8HuLEtb8YrVyAJ0t6OVM6w2_o1+P2=9Mt6Gw@mail.gmail.com> (raw)
In-Reply-To: <20200401134234.GR20696@hirez.programming.kicks-ass.net>
On Wed, Apr 1, 2020 at 6:42 AM Peter Zijlstra <peterz@infradead.org> wrote:
>
> On Fri, Mar 27, 2020 at 03:50:58PM -0700, Michel Lespinasse wrote:
>
> > @@ -26,6 +31,12 @@ static inline void mmap_write_unlock(struct mm_struct *mm)
> > up_write(&mm->mmap_sem);
> > }
> >
> > +/* Pairs with mmap_write_lock_nested() */
> > +static inline void mmap_write_unlock_nested(struct mm_struct *mm)
> > +{
> > + up_write(&mm->mmap_sem);
> > +}
> > +
> > static inline void mmap_downgrade_write_lock(struct mm_struct *mm)
> > {
> > downgrade_write(&mm->mmap_sem);
>
> Why does unlock_nested() make sense ?
I thought it would make things more explicit to match the nested lock
with the corresponding unlock site; however this information is not
used at the moment (i.e. the nested unlock is implemented identically
to the regular unlock).
Having the matching sites explicitly identified may help when
implementing lock instrumentation, or when changing the lock type
(another patchset I am working on needs to pass an explicit lock range
to the nested lock and unlock sites).
I'll admit this is not a super strong argument, and can be deferred to
when an actual need shows up in the future.
next prev parent reply other threads:[~2020-04-06 15:35 UTC|newest]
Thread overview: 73+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-27 22:50 [PATCH v3 00/10] Add a new mmap locking API wrapping mmap_sem calls Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 01/10] mmap locking API: initial implementation as rwsem wrappers Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-03-28 8:57 ` [PATCH v3 01/10] mmap locking API: initial implementation as rwsem wrappers (Michel Lespinasse) SeongJae Park
2020-03-27 22:50 ` [PATCH v3 02/10] MMU notifier: use the new mmap locking API Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 03/10] DMA reservations: " Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 04/10] mmap locking API: use coccinelle to convert mmap_sem rwsem call sites Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-03-27 22:50 ` [PATCH v3 05/10] mmap locking API: convert mmap_sem call sites missed by coccinelle Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-03-28 7:36 ` Markus Elfring
2020-03-28 7:36 ` [Cocci] " Markus Elfring
2020-03-28 7:47 ` Michel Lespinasse
2020-03-28 7:47 ` [Cocci] " Michel Lespinasse
2020-03-28 7:47 ` Michel Lespinasse
2020-03-28 8:39 ` [v3 " Markus Elfring
2020-03-28 8:39 ` [Cocci] " Markus Elfring
2020-03-28 8:53 ` Michel Lespinasse
2020-03-28 8:53 ` [Cocci] " Michel Lespinasse
2020-03-28 8:53 ` Michel Lespinasse
2020-03-28 9:01 ` Markus Elfring
2020-03-28 9:01 ` [Cocci] " Markus Elfring
2020-03-28 13:20 ` [v3 05/10] mmap locking API: Checking the Coccinelle software Markus Elfring
2020-03-28 13:20 ` [Cocci] " Markus Elfring
2020-03-28 13:42 ` Julia Lawall
2020-03-28 13:42 ` Julia Lawall
2020-03-28 13:42 ` Julia Lawall
2020-03-28 13:52 ` Markus Elfring
2020-03-28 13:52 ` Markus Elfring
2020-03-28 13:53 ` Julia Lawall
2020-03-28 13:53 ` Julia Lawall
2020-03-28 13:53 ` Julia Lawall
2020-03-28 14:00 ` Julia Lawall
2020-03-28 14:00 ` Julia Lawall
2020-03-28 14:00 ` Julia Lawall
2020-03-28 14:16 ` Markus Elfring
2020-03-28 14:16 ` Markus Elfring
2020-03-30 6:10 ` [v3 05/10] mmap locking API: Improving " Markus Elfring
2020-03-30 6:10 ` [Cocci] " Markus Elfring
2020-03-30 8:47 ` Julia Lawall
2020-03-30 8:47 ` Julia Lawall
2020-03-30 8:47 ` Julia Lawall
2020-03-30 10:15 ` Markus Elfring
2020-03-30 10:15 ` Markus Elfring
2020-03-30 10:20 ` Julia Lawall
2020-03-30 10:20 ` Julia Lawall
2020-03-30 10:20 ` Julia Lawall
2020-03-30 10:42 ` Markus Elfring
2020-03-30 10:42 ` Markus Elfring
2020-04-13 17:06 ` [PATCH v3 05/10] mmap locking API: convert mmap_sem call sites missed by coccinelle Daniel Jordan
2020-03-27 22:50 ` [PATCH v3 06/10] mmap locking API: convert nested write lock sites Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-04-01 13:42 ` Peter Zijlstra
2020-04-06 15:35 ` Michel Lespinasse [this message]
2020-04-06 15:35 ` Michel Lespinasse
2020-04-06 15:58 ` Peter Zijlstra
2020-03-27 22:50 ` [PATCH v3 07/10] mmap locking API: add mmap_read_release() and mmap_read_unlock_non_owner() Michel Lespinasse
2020-03-27 22:50 ` Michel Lespinasse
2020-04-01 13:46 ` Peter Zijlstra
2020-04-06 15:39 ` Michel Lespinasse
2020-04-06 15:39 ` Michel Lespinasse
2020-03-27 22:51 ` [PATCH v3 08/10] mmap locking API: add MMAP_LOCK_INITIALIZER Michel Lespinasse
2020-03-27 22:51 ` Michel Lespinasse
2020-03-27 22:51 ` [PATCH v3 09/10] mmap locking API: use lockdep_assert_held Michel Lespinasse
2020-03-27 22:51 ` Michel Lespinasse
2020-03-27 22:51 ` [PATCH v3 10/10] mmap locking API: rename mmap_sem to mmap_lock Michel Lespinasse
2020-03-27 22:51 ` Michel Lespinasse
2020-04-01 13:48 ` Peter Zijlstra
2020-04-06 15:49 ` Michel Lespinasse
2020-04-06 15:49 ` Michel Lespinasse
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