From: Jerome Glisse <j.glisse@gmail.com>
To: Andrew Morton <akpm@linux-foundation.org>
Cc: linux-kernel@vger.kernel.org, linux-mm@kvack.org,
"Linus Torvalds" <torvalds@linux-foundation.org>,
joro@8bytes.org, "Mel Gorman" <mgorman@suse.de>,
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"Brendan Conoboy" <blc@redhat.com>,
"Joe Donohue" <jdonohue@redhat.com>,
"Duncan Poole" <dpoole@nvidia.com>,
"Sherry Cheung" <SCheung@nvidia.com>,
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"John Hubbard" <jhubbard@nvidia.com>,
"Mark Hairgrove" <mhairgrove@nvidia.com>,
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"Arvind Gopalakrishnan" <arvindg@nvidia.com>,
"Shachar Raindel" <raindel@mellanox.com>,
"Liran Liss" <liranl@mellanox.com>,
"Roland Dreier" <roland@purestorage.com>,
"Ben Sander" <ben.sander@amd.com>,
"Greg Stoner" <Greg.Stoner@amd.com>,
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"Michael Mantor" <Michael.Mantor@amd.com>,
"Paul Blinzer" <Paul.Blinzer@amd.com>,
"Laurent Morichetti" <Laurent.Morichetti@amd.com>,
"Alexander Deucher" <Alexander.Deucher@amd.com>,
"Oded Gabbay" <Oded.Gabbay@amd.com>,
"Jérôme Glisse" <jglisse@redhat.com>
Subject: Re: [PATCH 3/7] mmu_notifier: pass through vma to invalidate_range and invalidate_page v3
Date: Fri, 25 Jul 2014 11:14:41 -0400 [thread overview]
Message-ID: <20140725151440.GA3218@gmail.com> (raw)
In-Reply-To: <20140724155157.c7e651db5f4947909123e602@linux-foundation.org>
On Thu, Jul 24, 2014 at 03:51:57PM -0700, Andrew Morton wrote:
> On Thu, 17 Jul 2014 14:46:49 -0400 j.glisse@gmail.com wrote:
>
> > New user of the mmu_notifier interface need to lookup vma in order to
> > perform the invalidation operation. Instead of redoing a vma lookup
> > inside the callback just pass through the vma from the call site where
> > it is already available.
>
> Well.. what's wrong with performing the vma lookup within the
> callback? Is it a correctness thing? Deadlock avoidance, for example?
>
> Or is it a performance thing? If so, that's a bit surprising - please
> provide details?
No i have no benchmark showing any issue on that, just that 99% of call
place to mmu_notifier already had the vma handy and i thought it would
be helpful to other but all current user are not using vma. So as there
is no strong argument in favor of this change if you feel it is unnecessary
and fear any kind of regression than just ignore it and i will live with
vma lookup inside my code.
Cheers,
Jerome
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next prev parent reply other threads:[~2014-07-25 15:14 UTC|newest]
Thread overview: 13+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-07-17 18:46 mmu_notifier: preparatory patches for hmm and or iommuv2 v6 j.glisse
2014-07-17 18:46 ` [PATCH 1/7] mmu_notifier: add call_srcu and sync function for listener to delay call and sync j.glisse
2014-07-21 15:01 ` Oded Gabbay
2014-07-29 15:04 ` Oded Gabbay
2014-07-29 20:48 ` Andrew Morton
2014-07-29 21:04 ` Oded Gabbay
2014-08-02 18:54 ` Oded Gabbay
2014-07-17 18:46 ` [PATCH 2/7] mmu_notifier: add event information to address invalidation v3 j.glisse
2014-07-17 18:46 ` [PATCH 3/7] mmu_notifier: pass through vma to invalidate_range and invalidate_page v3 j.glisse
2014-07-24 22:51 ` Andrew Morton
2014-07-25 15:14 ` Jerome Glisse [this message]
2014-07-24 15:46 ` mmu_notifier: preparatory patches for hmm and or iommuv2 v6 Jerome Glisse
2014-07-24 18:41 ` Oded Gabbay
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