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SubjectRe: [HMM v17 00/14] HMM (Heterogeneous Memory Management) v17
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On 01/27/2017 02:52 PM, Jérôme Glisse wrote:
> Cliff note: HMM offers 2 things (each standing on its own). First
> it allows to use device memory transparently inside any process
> without any modifications to process program code. Second it allows
> to mirror process address space on a device.
>
> Change since v16:
> - move HMM unaddressable device memory to its own radix tree and
> thus find_dev_pagemap() will no longer return HMM dev_pagemap
> - rename HMM migration helper (drop the prefix) and make them
> completely independent of HMM
>
> Migration can now be use to implement thing like multi-threaded
> copy or make use of specific memory allocator for destination
> memory.

We're about to do our usual testing with this, but there will be a brief pause first (the driver API
has changed slightly).

thanks
john h

>
> Work is under way to use this feature inside nouveau (the upstream
> open source driver for NVidia GPU) either 411 or 4.12 timeframe.
> But this patchset have been otherwise tested with the close source
> driver for NVidia GPU and thus we are confident it works and allow
> to use the hardware for seamless interaction between CPU and GPU
> in common address space of a process.
>
> I also discussed the features with other company and i am confident
> it can be use on other, yet, unrelease hardware.
>
> Please condiser applying for 4.11
>
>
> Know issues:
>
> Device memory pick some random unuse physical address range. Latter
> memory hotplug might fails because of this. Intention is to fix this
> in latter patchset to use physical address above the platform limit
> thus making sure that no real memory can be hotplug at conflicting
> address.
>
>
> Patchset overview:
>
> Patchset is divided into 3 features that can each be use independently
> from one another. First is changes to ZONE_DEVICE so we can have struct
> page for device un-addressable memory (patch 1-4 and 13-14). Second is
> process address space mirroring (patch 8 to 11), this allow to snapshot
> CPU page table and to keep the device page table synchronize with the
> CPU one.
>
> Last is a new page migration helper which allow migration for range of
> virtual address using hardware copy engine (patch 5-7 for new migrate
> function and 12 for migration of un-addressable memory).
>
>
> Future plan:
>
> In this patchset i restricted myself to set of core features what
> is missing:
> - force read only on CPU for memory duplication and GPU atomic
> - changes to mmu_notifier for optimization purposes
> - migration of file back page to device memory
>
> I plan to submit a couple more patchset to implement those features
> once core HMM is upstream.
>
> Git tree:
> https://cgit.freedesktop.org/~glisse/linux/log/?h=hmm-v17
>
>
> Previous patchset posting :
> v1 http://lwn.net/Articles/597289/
> v2 https://lkml.org/lkml/2014/6/12/559
> v3 https://lkml.org/lkml/2014/6/13/633
> v4 https://lkml.org/lkml/2014/8/29/423
> v5 https://lkml.org/lkml/2014/11/3/759
> v6 http://lwn.net/Articles/619737/
> v7 http://lwn.net/Articles/627316/
> v8 https://lwn.net/Articles/645515/
> v9 https://lwn.net/Articles/651553/
> v10 https://lwn.net/Articles/654430/
> v11 http://www.gossamer-threads.com/lists/linux/kernel/2286424
> v12 http://www.kernelhub.org/?msg=972982&p=2
> v13 https://lwn.net/Articles/706856/
> v14 https://lkml.org/lkml/2016/12/8/344
> v15 http://www.mail-archive.com/linux-kernel@vger.kernel.org/msg1304107.html
> v16 http://www.spinics.net/lists/linux-mm/msg119814.html
>
> Jérôme Glisse (14):
> mm/memory/hotplug: convert device bool to int to allow for more flags
> v2
> mm/ZONE_DEVICE/free-page: callback when page is freed v2
> mm/ZONE_DEVICE/unaddressable: add support for un-addressable device
> memory v3
> mm/ZONE_DEVICE/x86: add support for un-addressable device memory
> mm/migrate: add new boolean copy flag to migratepage() callback
> mm/migrate: new memory migration helper for use with device memory v3
> mm/migrate: migrate_vma() unmap page from vma while collecting pages
> mm/hmm: heterogeneous memory management (HMM for short)
> mm/hmm/mirror: mirror process address space on device with HMM helpers
> mm/hmm/mirror: helper to snapshot CPU page table
> mm/hmm/mirror: device page fault handler
> mm/hmm/migrate: support un-addressable ZONE_DEVICE page in migration
> mm/hmm/devmem: device memory hotplug using ZONE_DEVICE
> mm/hmm/devmem: dummy HMM device for ZONE_DEVICE memory v2
>
> MAINTAINERS | 7 +
> arch/ia64/mm/init.c | 23 +-
> arch/powerpc/mm/mem.c | 22 +-
> arch/s390/mm/init.c | 10 +-
> arch/sh/mm/init.c | 22 +-
> arch/tile/mm/init.c | 10 +-
> arch/x86/mm/init_32.c | 23 +-
> arch/x86/mm/init_64.c | 41 +-
> drivers/staging/lustre/lustre/llite/rw26.c | 8 +-
> fs/aio.c | 7 +-
> fs/btrfs/disk-io.c | 11 +-
> fs/hugetlbfs/inode.c | 9 +-
> fs/nfs/internal.h | 5 +-
> fs/nfs/write.c | 9 +-
> fs/proc/task_mmu.c | 10 +-
> fs/ubifs/file.c | 8 +-
> include/linux/balloon_compaction.h | 3 +-
> include/linux/fs.h | 13 +-
> include/linux/hmm.h | 464 +++++++++++
> include/linux/ioport.h | 1 +
> include/linux/memory_hotplug.h | 31 +-
> include/linux/memremap.h | 39 +-
> include/linux/migrate.h | 83 +-
> include/linux/mm_types.h | 5 +
> include/linux/swap.h | 18 +-
> include/linux/swapops.h | 67 ++
> kernel/fork.c | 2 +
> kernel/memremap.c | 31 +-
> mm/Kconfig | 38 +
> mm/Makefile | 1 +
> mm/balloon_compaction.c | 2 +-
> mm/hmm.c | 1235 ++++++++++++++++++++++++++++
> mm/memory.c | 64 +-
> mm/memory_hotplug.c | 14 +-
> mm/migrate.c | 659 ++++++++++++++-
> mm/mprotect.c | 12 +
> mm/rmap.c | 47 ++
> mm/zsmalloc.c | 12 +-
> 38 files changed, 2986 insertions(+), 80 deletions(-)
> create mode 100644 include/linux/hmm.h
> create mode 100644 mm/hmm.c
>
> --
> 2.4.3
>

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