From: Jerome Glisse <jglisse@redhat.com>
To: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: "akpm@linux-foundation.org" <akpm@linux-foundation.org>,
"linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
"linux-mm@kvack.org" <linux-mm@kvack.org>,
John Hubbard <jhubbard@nvidia.com>,
David Nellans <dnellans@nvidia.com>,
Mark Hairgrove <mhairgrove@nvidia.com>,
Sherry Cheung <SCheung@nvidia.com>,
Subhash Gutti <sgutti@nvidia.com>
Subject: Re: [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4
Date: Fri, 14 Jul 2017 20:55:55 -0400 [thread overview]
Message-ID: <20170715005554.GA12694@redhat.com> (raw)
In-Reply-To: <ca12b033-8ec5-84b0-c2aa-ea829e1194fa@nvidia.com>
On Fri, Jul 14, 2017 at 12:43:51PM -0700, Evgeny Baskakov wrote:
> On 7/13/17 1:16 PM, Jerome Glisse wrote:
> Hi Jerome,
>
> I have hit another kind of hang. Briefly, if a not yet allocated page faults
> on CPU during migration to device memory, any subsequent migration will fail
> for such page. Such a situation can trigger if a CPU page fault happens just
> immediately after migrate_vma() starts unmapping pages to migrate.
>
> Please find attached a reproducer based on the sample driver. In the
> hmm_test() function, an HMM_DMIRROR_MIGRATE request is triggered from a
> separate thread for not yet allocated pages (coming from malloc). In the
> same time, a HMM_DMIRROR_READ request is made for the same pages. This
> results in a sporadic app-side hang, because random number of pages never
> migrate to device memory.
>
> Note that if the pages are touched (initialized with data) prior to that,
> everything works as expected: all HMM_DMIRROR_READ and HMM_DMIRROR_MIGRATE
> requests eventually succeed. See comments in the hmm_test() function.
>
So pushed an updated hmm-next branch this should fix all issues you had.
Thought i am not sure about the test in this mail, all i see is that it
continously spit error messages but it does not hang (i let it run 20min
or so). Dunno if that is what expected. Let me know if this is still an
issue and if so what should be the expected output of this test program.
Cheers,
Jerome
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next prev parent reply other threads:[~2017-07-15 0:56 UTC|newest]
Thread overview: 66+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-05-22 16:51 [HMM 00/15] HMM (Heterogeneous Memory Management) v22 Jérôme Glisse
2017-05-22 16:51 ` [HMM 01/15] hmm: heterogeneous memory management documentation Jérôme Glisse
2017-05-22 16:51 ` [HMM 02/15] mm/hmm: heterogeneous memory management (HMM for short) v3 Jérôme Glisse
2017-05-22 16:51 ` [HMM 03/15] mm/hmm/mirror: mirror process address space on device with HMM helpers v3 Jérôme Glisse
2017-05-22 16:51 ` [HMM 04/15] mm/hmm/mirror: helper to snapshot CPU page table v3 Jérôme Glisse
2017-05-22 16:51 ` [HMM 05/15] mm/hmm/mirror: device page fault handler Jérôme Glisse
2017-05-22 16:51 ` [HMM 06/15] mm/memory_hotplug: introduce add_pages Jérôme Glisse
2017-05-22 16:51 ` [HMM 07/15] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v2 Jérôme Glisse
2017-05-22 21:17 ` Dan Williams
2017-05-23 21:36 ` [HMM 07/18] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v3 Jérôme Glisse
2017-05-23 8:36 ` [HMM 07/15] mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory v2 kbuild test robot
2017-05-22 16:51 ` [HMM 08/15] mm/ZONE_DEVICE: special case put_page() for device private pages Jérôme Glisse
2017-05-22 19:29 ` Dan Williams
2017-05-22 20:14 ` Jerome Glisse
2017-05-22 20:19 ` Dan Williams
2017-05-22 21:14 ` Jerome Glisse
2017-05-22 20:22 ` Hugh Dickins
2017-05-22 21:17 ` Jerome Glisse
2017-05-23 9:34 ` kbuild test robot
2017-05-23 13:23 ` Kirill A. Shutemov
2017-05-23 21:37 ` [HMM 08/18] mm/ZONE_DEVICE: special case put_page() for device private pages v2 Jérôme Glisse
2017-05-22 16:52 ` [HMM 09/15] mm/hmm/devmem: device memory hotplug using ZONE_DEVICE v4 Jérôme Glisse
2017-05-23 21:37 ` [HMM 09/18] mm/hmm/devmem: device memory hotplug using ZONE_DEVICE v5 Jérôme Glisse
2017-05-22 16:52 ` [HMM 10/15] mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v3 Jérôme Glisse
2017-05-22 16:52 ` [HMM 11/15] mm/migrate: new migrate mode MIGRATE_SYNC_NO_COPY Jérôme Glisse
2017-05-22 16:52 ` [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4 Jérôme Glisse
2017-05-23 18:07 ` Reza Arbab
2017-06-27 0:07 ` Evgeny Baskakov
2017-06-30 23:19 ` Evgeny Baskakov
2017-07-01 0:57 ` Jerome Glisse
2017-07-01 2:06 ` Evgeny Baskakov
2017-07-10 22:59 ` Evgeny Baskakov
2017-07-10 23:43 ` Jerome Glisse
2017-07-11 0:17 ` Evgeny Baskakov
2017-07-11 0:54 ` Jerome Glisse
2017-07-20 21:05 ` Evgeny Baskakov
2017-07-10 23:44 ` Evgeny Baskakov
2017-07-11 18:29 ` Jerome Glisse
2017-07-11 18:42 ` Evgeny Baskakov
2017-07-11 18:49 ` Jerome Glisse
2017-07-11 19:35 ` Evgeny Baskakov
2017-07-13 20:16 ` Jerome Glisse
2017-07-14 5:32 ` Evgeny Baskakov
2017-07-14 19:43 ` Evgeny Baskakov
2017-07-15 0:55 ` Jerome Glisse [this message]
2017-07-15 5:04 ` Evgeny Baskakov
2017-07-21 1:00 ` Evgeny Baskakov
2017-07-21 1:33 ` Jerome Glisse
2017-07-21 22:01 ` Evgeny Baskakov
2017-07-25 22:45 ` Evgeny Baskakov
2017-07-26 19:14 ` Jerome Glisse
2017-05-22 16:52 ` [HMM 13/15] mm/migrate: migrate_vma() unmap page from vma while collecting pages Jérôme Glisse
2017-05-22 16:52 ` [HMM 14/15] mm/migrate: support un-addressable ZONE_DEVICE page in migration v2 Jérôme Glisse
2017-05-22 16:52 ` [HMM 15/15] mm/migrate: allow migrate_vma() to alloc new page on empty entry v2 Jérôme Glisse
2017-05-23 22:02 ` [HMM 00/15] HMM (Heterogeneous Memory Management) v22 Jerome Glisse
2017-05-23 22:05 ` Andrew Morton
2017-05-24 1:55 ` Balbir Singh
2017-05-24 17:53 ` Jerome Glisse
2017-06-01 2:04 ` Balbir Singh
2017-06-01 22:38 ` Jerome Glisse
2017-06-03 9:18 ` Balbir Singh
2017-05-24 17:20 [HMM 00/15] HMM (Heterogeneous Memory Management) v23 Jérôme Glisse
2017-05-24 17:20 ` [HMM 12/15] mm/migrate: new memory migration helper for use with device memory v4 Jérôme Glisse
2017-05-31 3:59 ` Balbir Singh
2017-06-01 22:35 ` Jerome Glisse
2017-06-07 9:02 ` Balbir Singh
2017-06-07 14:06 ` Jerome Glisse
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