Re: [PATCH v6 0/8] mmu notifier provide context informations

[Jerome Glisse <jglisse@redhat.com>]

Andrew anything blocking this for 5.2 ? Should i ask people (ie the end
user of this) to re-ack v6 (it is the same as previous version just rebase
and dropped kvm bits).



On Tue, Mar 26, 2019 at 12:47:39PM -0400, jglisse@redhat.com wrote:
> From: Jérôme Glisse <jglisse@redhat.com>
> 
> (Andrew this apply on top of my HMM patchset as otherwise you will have
>  conflict with changes to mm/hmm.c)
> 
> Changes since v5:
>     - drop KVM bits waiting for KVM people to express interest if they
>       do not then i will post patchset to remove change_pte_notify as
>       without the changes in v5 change_pte_notify is just useless (it
>       it is useless today upstream it is just wasting cpu cycles)
>     - rebase on top of lastest Linus tree
> 
> Previous cover letter with minor update:
> 
> 
> Here i am not posting users of this, they already have been posted to
> appropriate mailing list [6] and will be merge through the appropriate
> tree once this patchset is upstream.
> 
> Note that this serie does not change any behavior for any existing
> code. It just pass down more information to mmu notifier listener.
> 
> The rational for this patchset:
> 
> CPU page table update can happens for many reasons, not only as a
> result of a syscall (munmap(), mprotect(), mremap(), madvise(), ...)
> but also as a result of kernel activities (memory compression, reclaim,
> migration, ...).
> 
> This patch introduce a set of enums that can be associated with each
> of the events triggering a mmu notifier:
> 
>     - UNMAP: munmap() or mremap()
>     - CLEAR: page table is cleared (migration, compaction, reclaim, ...)
>     - PROTECTION_VMA: change in access protections for the range
>     - PROTECTION_PAGE: change in access protections for page in the range
>     - SOFT_DIRTY: soft dirtyness tracking
> 
> Being able to identify munmap() and mremap() from other reasons why the
> page table is cleared is important to allow user of mmu notifier to
> update their own internal tracking structure accordingly (on munmap or
> mremap it is not longer needed to track range of virtual address as it
> becomes invalid). Without this serie, driver are force to assume that
> every notification is an munmap which triggers useless trashing within
> drivers that associate structure with range of virtual address. Each
> driver is force to free up its tracking structure and then restore it
> on next device page fault. With this serie we can also optimize device
> page table update [6].
> 
> More over this can also be use to optimize out some page table updates
> like for KVM where we can update the secondary MMU directly from the
> callback instead of clearing it.
> 
> ACKS AMD/RADEON https://lkml.org/lkml/2019/2/1/395
> ACKS RDMA https://lkml.org/lkml/2018/12/6/1473
> 
> Cheers,
> Jérôme
> 
> [1] v1 https://lkml.org/lkml/2018/3/23/1049
> [2] v2 https://lkml.org/lkml/2018/12/5/10
> [3] v3 https://lkml.org/lkml/2018/12/13/620
> [4] v4 https://lkml.org/lkml/2019/1/23/838
> [5] v5 https://lkml.org/lkml/2019/2/19/752
> [6] patches to use this:
>     https://lkml.org/lkml/2019/1/23/833
>     https://lkml.org/lkml/2019/1/23/834
>     https://lkml.org/lkml/2019/1/23/832
>     https://lkml.org/lkml/2019/1/23/831
> 
> Cc: Andrew Morton <akpm@linux-foundation.org>
> Cc: linux-mm@kvack.org
> Cc: Christian König <christian.koenig@amd.com>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Jani Nikula <jani.nikula@linux.intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> Cc: Jan Kara <jack@suse.cz>
> Cc: Andrea Arcangeli <aarcange@redhat.com>
> Cc: Peter Xu <peterx@redhat.com>
> Cc: Felix Kuehling <Felix.Kuehling@amd.com>
> Cc: Jason Gunthorpe <jgg@mellanox.com>
> Cc: Ross Zwisler <zwisler@kernel.org>
> Cc: Dan Williams <dan.j.williams@intel.com>
> Cc: Paolo Bonzini <pbonzini@redhat.com>
> Cc: Alex Deucher <alexander.deucher@amd.com>
> Cc: Radim Krčmář <rkrcmar@redhat.com>
> Cc: Michal Hocko <mhocko@kernel.org>
> Cc: Christian Koenig <christian.koenig@amd.com>
> Cc: Ben Skeggs <bskeggs@redhat.com>
> Cc: Ralph Campbell <rcampbell@nvidia.com>
> Cc: John Hubbard <jhubbard@nvidia.com>
> Cc: kvm@vger.kernel.org
> Cc: dri-devel@lists.freedesktop.org
> Cc: linux-rdma@vger.kernel.org
> Cc: Arnd Bergmann <arnd@arndb.de>
> 
> Jérôme Glisse (8):
>   mm/mmu_notifier: helper to test if a range invalidation is blockable
>   mm/mmu_notifier: convert user range->blockable to helper function
>   mm/mmu_notifier: convert mmu_notifier_range->blockable to a flags
>   mm/mmu_notifier: contextual information for event enums
>   mm/mmu_notifier: contextual information for event triggering
>     invalidation v2
>   mm/mmu_notifier: use correct mmu_notifier events for each invalidation
>   mm/mmu_notifier: pass down vma and reasons why mmu notifier is
>     happening v2
>   mm/mmu_notifier: mmu_notifier_range_update_to_read_only() helper
> 
>  drivers/gpu/drm/amd/amdgpu/amdgpu_mn.c  |  8 ++--
>  drivers/gpu/drm/i915/i915_gem_userptr.c |  2 +-
>  drivers/gpu/drm/radeon/radeon_mn.c      |  4 +-
>  drivers/infiniband/core/umem_odp.c      |  5 +-
>  drivers/xen/gntdev.c                    |  6 +--
>  fs/proc/task_mmu.c                      |  3 +-
>  include/linux/mmu_notifier.h            | 63 +++++++++++++++++++++++--
>  kernel/events/uprobes.c                 |  3 +-
>  mm/hmm.c                                |  6 +--
>  mm/huge_memory.c                        | 14 +++---
>  mm/hugetlb.c                            | 12 +++--
>  mm/khugepaged.c                         |  3 +-
>  mm/ksm.c                                |  6 ++-
>  mm/madvise.c                            |  3 +-
>  mm/memory.c                             | 25 ++++++----
>  mm/migrate.c                            |  5 +-
>  mm/mmu_notifier.c                       | 12 ++++-
>  mm/mprotect.c                           |  4 +-
>  mm/mremap.c                             |  3 +-
>  mm/oom_kill.c                           |  3 +-
>  mm/rmap.c                               |  6 ++-
>  virt/kvm/kvm_main.c                     |  3 +-
>  22 files changed, 147 insertions(+), 52 deletions(-)
> 
> -- 
> 2.20.1
>