From: Jan Kara <jack@suse.cz>
To: John Hubbard <jhubbard@nvidia.com>
Cc: Hillf Danton <hdanton@sina.com>, linux-mm <linux-mm@kvack.org>,
Andrew Morton <akpm@linux-foundation.org>,
linux-kernel <linux-kernel@vger.kernel.org>,
Vlastimil Babka <vbabka@suse.cz>, Jan Kara <jack@suse.cz>,
Mel Gorman <mgorman@suse.de>, Jerome Glisse <jglisse@redhat.com>,
Dan Williams <dan.j.williams@intel.com>,
Ira Weiny <ira.weiny@intel.com>, Christoph Hellwig <hch@lst.de>,
Jonathan Corbet <corbet@lwn.net>
Subject: Re: [RFC] mm: gup: add helper page_try_gup_pin(page)
Date: Mon, 4 Nov 2019 09:13:17 +0100 [thread overview]
Message-ID: <20191104081317.GB22379@quack2.suse.cz> (raw)
In-Reply-To: <8df14660-2ce3-eda8-dc33-c4d092915656@nvidia.com>
On Sun 03-11-19 22:09:03, John Hubbard wrote:
> On 11/3/19 8:34 PM, Hillf Danton wrote:
> > future, we have options for instance that gupers periodically release
> > their references and re-pin pages after data sync the same way as the
> > current flusher does.
> >
>
> That's one idea. I don't see it as viable, given the behavior of, say,
> a compute process running OpenCL jobs on a GPU that is connected via
> a network or Infiniband card--the idea of "pause" really looks more like
> "tear down the complicated multi-driver connection, writeback, then set it
> all up again", I suspect. (And if we could easily interrupt the job, we'd
> probably really be running with a page-fault-capable GPU plus and IB card
> that does ODP, plus HMM, and we wouldn't need to gup-pin anyway...)
>
> Anyway, this is not amenable to quick fixes, because the problem is
> a couple of missing design pieces. Which we're working on putting in.
> But meanwhile, smaller changes such as this one are just going to move
> the problems to different places, rather than solving them. So it's best
> not to do that.
Yeah, fully agreed here. Quick half baked fixes will make the current messy
situation even worse...
Honza
--
Jan Kara <jack@suse.com>
SUSE Labs, CR
next prev parent reply other threads:[~2019-11-04 8:13 UTC|newest]
Thread overview: 9+ messages / expand[flat|nested] mbox.gz Atom feed top
[not found] <20191103112113.8256-1-hdanton@sina.com>
2019-11-03 20:20 ` [RFC] mm: gup: add helper page_try_gup_pin(page) John Hubbard
[not found] ` <20191104043420.15648-1-hdanton@sina.com>
2019-11-04 6:09 ` John Hubbard
2019-11-04 8:13 ` Jan Kara [this message]
[not found] ` <20191104102050.15988-1-hdanton@sina.com>
2019-11-04 19:03 ` Jerome Glisse
2019-11-05 8:56 ` David Hildenbrand
[not found] ` <20191105042755.7292-1-hdanton@sina.com>
2019-11-05 15:54 ` Jerome Glisse
[not found] ` <20191106092240.1712-1-hdanton@sina.com>
2019-11-06 15:46 ` Jerome Glisse
[not found] ` <20191107095017.17544-1-hdanton@sina.com>
2019-11-07 14:57 ` Jerome Glisse
[not found] ` <20191108093837.1696-1-hdanton@sina.com>
2019-11-08 13:59 ` Jerome Glisse
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