From: Bob Liu <liubo95@huawei.com>
To: "Jérôme Glisse" <jglisse@redhat.com>,
linux-kernel@vger.kernel.org, linux-mm@kvack.org
Cc: John Hubbard <jhubbard@nvidia.com>,
David Nellans <dnellans@nvidia.com>,
Dan Williams <dan.j.williams@intel.com>,
Balbir Singh <bsingharora@gmail.com>,
Michal Hocko <mhocko@kernel.org>
Subject: Re: [PATCH 0/6] Cache coherent device memory (CDM) with HMM v5
Date: Tue, 18 Jul 2017 11:26:51 +0800 [thread overview]
Message-ID: <2d534afc-28c5-4c81-c452-7e4c013ab4d0@huawei.com> (raw)
In-Reply-To: <20170713211532.970-1-jglisse@redhat.com>
On 2017/7/14 5:15, JA(C)rA'me Glisse wrote:
> Sorry i made horrible mistake on names in v4, i completly miss-
> understood the suggestion. So here i repost with proper naming.
> This is the only change since v3. Again sorry about the noise
> with v4.
>
> Changes since v4:
> - s/DEVICE_HOST/DEVICE_PUBLIC
>
> Git tree:
> https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-cdm-v5
>
>
> Cache coherent device memory apply to architecture with system bus
> like CAPI or CCIX. Device connected to such system bus can expose
> their memory to the system and allow cache coherent access to it
> from the CPU.
>
> Even if for all intent and purposes device memory behave like regular
> memory, we still want to manage it in isolation from regular memory.
> Several reasons for that, first and foremost this memory is less
> reliable than regular memory if the device hangs because of invalid
> commands we can loose access to device memory. Second CPU access to
> this memory is expected to be slower than to regular memory. Third
> having random memory into device means that some of the bus bandwith
> wouldn't be available to the device but would be use by CPU access.
>
> This is why we want to manage such memory in isolation from regular
> memory. Kernel should not try to use this memory even as last resort
> when running out of memory, at least for now.
>
I think set a very large node distance for "Cache Coherent Device Memory" may be a easier way to address these concerns.
--
Regards,
Bob Liu
> This patchset add a new type of ZONE_DEVICE memory (DEVICE_HOST)
> that is use to represent CDM memory. This patchset build on top of
> the HMM patchset that already introduce a new type of ZONE_DEVICE
> memory for private device memory (see HMM patchset).
>
> The end result is that with this patchset if a device is in use in
> a process you might have private anonymous memory or file back
> page memory using ZONE_DEVICE (DEVICE_HOST). Thus care must be
> taken to not overwritte lru fields of such pages.
>
> Hence all core mm changes are done to address assumption that any
> process memory is back by a regular struct page that is part of
> the lru. ZONE_DEVICE page are not on the lru and the lru pointer
> of struct page are use to store device specific informations.
>
> Thus this patchset update all code path that would make assumptions
> about lruness of a process page.
>
> patch 01 - rename DEVICE_PUBLIC to DEVICE_HOST to free DEVICE_PUBLIC name
> patch 02 - add DEVICE_PUBLIC type to ZONE_DEVICE (all core mm changes)
> patch 03 - add an helper to HMM for hotplug of CDM memory
> patch 04 - preparatory patch for memory controller changes (memch)
> patch 05 - update memory controller to properly handle
> ZONE_DEVICE pages when uncharging
> patch 06 - documentation patch
>
> Previous posting:
> v1 https://lkml.org/lkml/2017/4/7/638
> v2 https://lwn.net/Articles/725412/
> v3 https://lwn.net/Articles/727114/
> v4 https://lwn.net/Articles/727692/
>
> JA(C)rA'me Glisse (6):
> mm/zone-device: rename DEVICE_PUBLIC to DEVICE_HOST
> mm/device-public-memory: device memory cache coherent with CPU v4
> mm/hmm: add new helper to hotplug CDM memory region v3
> mm/memcontrol: allow to uncharge page without using page->lru field
> mm/memcontrol: support MEMORY_DEVICE_PRIVATE and MEMORY_DEVICE_PUBLIC
> v3
> mm/hmm: documents how device memory is accounted in rss and memcg
>
> Documentation/vm/hmm.txt | 40 ++++++++
> fs/proc/task_mmu.c | 2 +-
> include/linux/hmm.h | 7 +-
> include/linux/ioport.h | 1 +
> include/linux/memremap.h | 25 ++++-
> include/linux/mm.h | 20 ++--
> kernel/memremap.c | 19 ++--
> mm/Kconfig | 11 +++
> mm/gup.c | 7 ++
> mm/hmm.c | 89 ++++++++++++++++--
> mm/madvise.c | 2 +-
> mm/memcontrol.c | 231 ++++++++++++++++++++++++++++++-----------------
> mm/memory.c | 46 +++++++++-
> mm/migrate.c | 57 +++++++-----
> mm/swap.c | 11 +++
> 15 files changed, 434 insertions(+), 134 deletions(-)
>
--
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next prev parent reply other threads:[~2017-07-18 3:33 UTC|newest]
Thread overview: 43+ messages / expand[flat|nested] mbox.gz Atom feed top
2017-07-13 21:15 [PATCH 0/6] Cache coherent device memory (CDM) with HMM v5 Jérôme Glisse
2017-07-13 21:15 ` [PATCH 1/6] mm/zone-device: rename DEVICE_PUBLIC to DEVICE_HOST Jérôme Glisse
2017-07-17 9:09 ` Balbir Singh
2017-07-13 21:15 ` [PATCH 2/6] mm/device-public-memory: device memory cache coherent with CPU v4 Jérôme Glisse
2017-07-13 23:01 ` Balbir Singh
2017-07-13 21:15 ` [PATCH 3/6] mm/hmm: add new helper to hotplug CDM memory region v3 Jérôme Glisse
2017-07-13 21:15 ` [PATCH 4/6] mm/memcontrol: allow to uncharge page without using page->lru field Jérôme Glisse
2017-07-17 9:10 ` Balbir Singh
2017-07-13 21:15 ` [PATCH 5/6] mm/memcontrol: support MEMORY_DEVICE_PRIVATE and MEMORY_DEVICE_PUBLIC v3 Jérôme Glisse
2017-07-17 9:15 ` Balbir Singh
2017-07-13 21:15 ` [PATCH 6/6] mm/hmm: documents how device memory is accounted in rss and memcg Jérôme Glisse
2017-07-14 13:26 ` Michal Hocko
2017-07-18 3:26 ` Bob Liu [this message]
2017-07-18 15:38 ` [PATCH 0/6] Cache coherent device memory (CDM) with HMM v5 Jerome Glisse
2017-07-19 1:46 ` Bob Liu
2017-07-19 2:25 ` Jerome Glisse
2017-07-19 9:09 ` Bob Liu
2017-07-20 15:03 ` Jerome Glisse
2017-07-21 1:15 ` Bob Liu
2017-07-21 1:41 ` Jerome Glisse
2017-07-21 2:10 ` Bob Liu
2017-07-21 12:01 ` Bob Liu
2017-07-21 15:21 ` Jerome Glisse
2017-07-21 3:48 ` Dan Williams
2017-07-21 15:22 ` Jerome Glisse
2017-09-05 19:36 ` Jerome Glisse
2017-09-09 23:22 ` Bob Liu
2017-09-11 23:36 ` Jerome Glisse
2017-09-12 1:02 ` Bob Liu
2017-09-12 16:17 ` Jerome Glisse
2017-09-26 9:56 ` Bob Liu
2017-09-26 16:16 ` Jerome Glisse
2017-09-30 2:57 ` Bob Liu
2017-09-30 22:49 ` Jerome Glisse
2017-10-11 13:15 ` Bob Liu
2017-10-12 15:37 ` Jerome Glisse
2017-11-16 2:10 ` chet l
2017-11-16 2:44 ` Jerome Glisse
2017-11-16 3:23 ` chetan L
2017-11-16 3:29 ` chetan L
2017-11-16 21:29 ` Jerome Glisse
2017-11-16 22:41 ` chetan L
2017-11-16 23:11 ` Jerome Glisse
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