From: Jason Gunthorpe <jgg@ziepe.ca>
To: Jann Horn <jannh@google.com>
Cc: Andrew Morton <akpm@linux-foundation.org>,
linux-mm@kvack.org, linux-kernel@vger.kernel.org,
"Eric W . Biederman" <ebiederm@xmission.com>,
Michel Lespinasse <walken@google.com>,
Mauro Carvalho Chehab <mchehab@kernel.org>,
Sakari Ailus <sakari.ailus@linux.intel.com>
Subject: Re: [PATCH 1/4] mm/gup_benchmark: Take the mmap lock around GUP
Date: Wed, 30 Sep 2020 09:20:14 -0300 [thread overview]
Message-ID: <20200930122014.GB9916@ziepe.ca> (raw)
In-Reply-To: <CAG48ez3SG6ngZLtasxJ6LABpOnqCz5-QHqb0B4k44TQ8F9n6+w@mail.gmail.com>
On Tue, Sep 29, 2020 at 06:19:59PM -0700, Jann Horn wrote:
> To be safe against concurrent changes to the VMA tree, we must take the
> mmap lock around GUP operations (excluding the GUP-fast family of
> operations, which will take the mmap lock by themselves if necessary).
>
> This code is only for testing, and it's only reachable by root through
> debugfs, so this doesn't really have any impact; however, if we want to add
> lockdep asserts into the GUP path, we need to have clean locking here.
>
> Signed-off-by: Jann Horn <jannh@google.com>
> ---
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Jason
next prev parent reply other threads:[~2020-09-30 12:20 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-09-30 1:19 [PATCH 1/4] mm/gup_benchmark: Take the mmap lock around GUP Jann Horn
2020-09-30 1:35 ` Jann Horn
2020-09-30 12:20 ` Jason Gunthorpe [this message]
2020-09-30 21:15 ` John Hubbard
2020-09-30 23:21 ` Michel Lespinasse
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