From mboxrd@z Thu Jan  1 00:00:00 1970
From: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Subject: Re: [RFC] Heterogeneous memory management (mirror process address
 space on a device mmu).
Date: Sat, 10 May 2014 14:28:35 +1000
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Cc: Linus Torvalds <torvalds@linux-foundation.org>,
        Peter Zijlstra
 <peterz@infradead.org>, linux-mm <linux-mm@kvack.org>,
        Linux Kernel Mailing
 List <linux-kernel@vger.kernel.org>,
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 Anvin" <hpa@zytor.com>,
        Andrew Morton <akpm@linux-foundation.org>,
        Linda
 Wang <lwang@redhat.com>, Kevin E Martin <kem@redhat.com>,
        Jerome Glisse
 <jglisse@redhat.com>,
        Andrea Arcangeli <aarcange@redhat.com>,
        Johannes
 Weiner <jweiner@redhat.com>,
        Larry Woodman <lwoodman@redhat.com>, Rik van
 Riel <riel@redhat.com>,
        Dave Airlie <airlied@redhat.com>, Jeff Law
 <law@redhat.com>,
        Brendan Conoboy <blc@redhat.com>, Joe Donohue
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        Duncan Poole <dpoole@nvidia.com>, Sherry Cheung
 <SCheung@nvidia.com>,
To: Jerome Glisse <j.glisse@gmail.com>
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On Thu, 2014-05-08 at 21:26 -0400, Jerome Glisse wrote:
> Otherwise i have no other choice than to add something like mmu_notifier
> in the place where there can a be race (huge page split, cow, ...). Which
> sounds like a bad idea to me when mmu_notifier is perfect for the job.

Even there, how are you going to find a sleepable context ? All that stuff
has the PTL held.

Cheers,
Ben.



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