linux-stable.git/include/linux/mm_types.h, branch v5.6.2

Merge tag 'drm-next-2020-02-04' of git://anongit.freedesktop.org/drm/drm

2020-02-04T07:21:04+00:00

Pull drm ttm/mm updates from Dave Airlie:
 "Thomas Hellstrom has some more changes to the TTM layer that needed a
  patch to the mm subsystem.

  This adds a new mm API vmf_insert_mixed_prot to avoid an ugly hack
  that has limitations in the TTM layer"

* tag 'drm-next-2020-02-04' of git://anongit.freedesktop.org/drm/drm:
  mm, drm/ttm: Fix vm page protection handling
  mm: Add a vmf_insert_mixed_prot() function

mm: Add a vmf_insert_mixed_prot() function

2020-01-16T09:32:33+00:00

The TTM module today uses a hack to be able to set a different page
protection than struct vm_area_struct::vm_page_prot. To be able to do
this properly, add the needed vm functionality as vmf_insert_mixed_prot().

Cc: Andrew Morton 
Cc: Michal Hocko 
Cc: "Matthew Wilcox (Oracle)" 
Cc: "Kirill A. Shutemov" 
Cc: Ralph Campbell 
Cc: "Jérôme Glisse" 
Cc: "Christian König" 
Signed-off-by: Thomas Hellstrom 
Acked-by: Christian König 
Acked-by: Michal Hocko 
Acked-by: Andrew Morton

mm/mmu_notifier: Rename struct mmu_notifier_mm to mmu_notifier_subscriptions

2020-01-14T15:54:47+00:00

The name mmu_notifier_mm implies that the thing is a mm_struct pointer,
and is difficult to abbreviate. The struct is actually holding the
interval tree and hlist containing the notifiers subscribed to a mm.

Use 'subscriptions' as the variable name for this struct instead of the
really terrible and misleading 'mmn_mm'.

Signed-off-by: Jason Gunthorpe

mm: thp: handle page cache THP correctly in PageTransCompoundMap

2019-11-06T16:28:58+00:00

We have a usecase to use tmpfs as QEMU memory backend and we would like
to take the advantage of THP as well.  But, our test shows the EPT is
not PMD mapped even though the underlying THP are PMD mapped on host.
The number showed by /sys/kernel/debug/kvm/largepage is much less than
the number of PMD mapped shmem pages as the below:

  7f2778200000-7f2878200000 rw-s 00000000 00:14 262232 /dev/shm/qemu_back_mem.mem.Hz2hSf (deleted)
  Size:            4194304 kB
  [snip]
  AnonHugePages:         0 kB
  ShmemPmdMapped:   579584 kB
  [snip]
  Locked:                0 kB

  cat /sys/kernel/debug/kvm/largepages
  12

And some benchmarks do worse than with anonymous THPs.

By digging into the code we figured out that commit 127393fbe597 ("mm:
thp: kvm: fix memory corruption in KVM with THP enabled") checks if
there is a single PTE mapping on the page for anonymous THP when setting
up EPT map.  But the _mapcount < 0 check doesn't work for page cache THP
since every subpage of page cache THP would get _mapcount inc'ed once it
is PMD mapped, so PageTransCompoundMap() always returns false for page
cache THP.  This would prevent KVM from setting up PMD mapped EPT entry.

So we need handle page cache THP correctly.  However, when page cache
THP's PMD gets split, kernel just remove the map instead of setting up
PTE map like what anonymous THP does.  Before KVM calls get_user_pages()
the subpages may get PTE mapped even though it is still a THP since the
page cache THP may be mapped by other processes at the mean time.

Checking its _mapcount and whether the THP has PTE mapped or not.
Although this may report some false negative cases (PTE mapped by other
processes), it looks not trivial to make this accurate.

With this fix /sys/kernel/debug/kvm/largepage would show reasonable
pages are PMD mapped by EPT as the below:

  7fbeaee00000-7fbfaee00000 rw-s 00000000 00:14 275464 /dev/shm/qemu_back_mem.mem.SKUvat (deleted)
  Size:            4194304 kB
  [snip]
  AnonHugePages:         0 kB
  ShmemPmdMapped:   557056 kB
  [snip]
  Locked:                0 kB

  cat /sys/kernel/debug/kvm/largepages
  271

And the benchmarks are as same as anonymous THPs.

[yang.shi@linux.alibaba.com: v4]
  Link: http://lkml.kernel.org/r/1571865575-42913-1-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1571769577-89735-1-git-send-email-yang.shi@linux.alibaba.com
Fixes: dd78fedde4b9 ("rmap: support file thp")
Signed-off-by: Yang Shi 
Reported-by: Gang Deng 
Tested-by: Gang Deng 
Suggested-by: Hugh Dickins 
Acked-by: Kirill A. Shutemov 
Cc: Andrea Arcangeli 
Cc: Matthew Wilcox 
Cc: 	[4.8+]
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip

2019-09-28T19:39:07+00:00

Pull scheduler fixes from Ingo Molnar:

 - Apply a number of membarrier related fixes and cleanups, which fixes
   a use-after-free race in the membarrier code

 - Introduce proper RCU protection for tasks on the runqueue - to get
   rid of the subtle task_rcu_dereference() interface that was easy to
   get wrong

 - Misc fixes, but also an EAS speedup

* 'sched-urgent-for-linus' of git://git.kernel.org/pub/scm/linux/kernel/git/tip/tip:
  sched/fair: Avoid redundant EAS calculation
  sched/core: Remove double update_max_interval() call on CPU startup
  sched/core: Fix preempt_schedule() interrupt return comment
  sched/fair: Fix -Wunused-but-set-variable warnings
  sched/core: Fix migration to invalid CPU in __set_cpus_allowed_ptr()
  sched/membarrier: Return -ENOMEM to userspace on memory allocation failure
  sched/membarrier: Skip IPIs when mm->mm_users == 1
  selftests, sched/membarrier: Add multi-threaded test
  sched/membarrier: Fix p->mm->membarrier_state racy load
  sched/membarrier: Call sync_core only before usermode for same mm
  sched/membarrier: Remove redundant check
  sched/membarrier: Fix private expedited registration check
  tasks, sched/core: RCUify the assignment of rq->curr
  tasks, sched/core: With a grace period after finish_task_switch(), remove unnecessary code
  tasks, sched/core: Ensure tasks are available for a grace period after leaving the runqueue
  tasks: Add a count of task RCU users
  sched/core: Convert vcpu_is_preempted() from macro to an inline function
  sched/fair: Remove unused cfs_rq_clock_task() function

sched/membarrier: Fix p->mm->membarrier_state racy load

2019-09-25T15:42:30+00:00

The membarrier_state field is located within the mm_struct, which
is not guaranteed to exist when used from runqueue-lock-free iteration
on runqueues by the membarrier system call.

Copy the membarrier_state from the mm_struct into the scheduler runqueue
when the scheduler switches between mm.

When registering membarrier for mm, after setting the registration bit
in the mm membarrier state, issue a synchronize_rcu() to ensure the
scheduler observes the change. In order to take care of the case
where a runqueue keeps executing the target mm without swapping to
other mm, iterate over each runqueue and issue an IPI to copy the
membarrier_state from the mm_struct into each runqueue which have the
same mm which state has just been modified.

Move the mm membarrier_state field closer to pgd in mm_struct to use
a cache line already touched by the scheduler switch_mm.

The membarrier_execve() (now membarrier_exec_mmap) hook now needs to
clear the runqueue's membarrier state in addition to clear the mm
membarrier state, so move its implementation into the scheduler
membarrier code so it can access the runqueue structure.

Add memory barrier in membarrier_exec_mmap() prior to clearing
the membarrier state, ensuring memory accesses executed prior to exec
are not reordered with the stores clearing the membarrier state.

As suggested by Linus, move all membarrier.c RCU read-side locks outside
of the for each cpu loops.

Suggested-by: Linus Torvalds 
Signed-off-by: Mathieu Desnoyers 
Signed-off-by: Peter Zijlstra (Intel) 
Cc: Chris Metcalf 
Cc: Christoph Lameter 
Cc: Eric W. Biederman 
Cc: Kirill Tkhai 
Cc: Mike Galbraith 
Cc: Oleg Nesterov 
Cc: Paul E. McKenney 
Cc: Peter Zijlstra 
Cc: Russell King - ARM Linux admin 
Cc: Thomas Gleixner 
Link: https://lkml.kernel.org/r/20190919173705.2181-5-mathieu.desnoyers@efficios.com
Signed-off-by: Ingo Molnar

mm: thp: make deferred split shrinker memcg aware

2019-09-24T22:54:11+00:00

Currently THP deferred split shrinker is not memcg aware, this may cause
premature OOM with some configuration.  For example the below test would
run into premature OOM easily:

$ cgcreate -g memory:thp
$ echo 4G > /sys/fs/cgroup/memory/thp/memory/limit_in_bytes
$ cgexec -g memory:thp transhuge-stress 4000

transhuge-stress comes from kernel selftest.

It is easy to hit OOM, but there are still a lot THP on the deferred split
queue, memcg direct reclaim can't touch them since the deferred split
shrinker is not memcg aware.

Convert deferred split shrinker memcg aware by introducing per memcg
deferred split queue.  The THP should be on either per node or per memcg
deferred split queue if it belongs to a memcg.  When the page is
immigrated to the other memcg, it will be immigrated to the target memcg's
deferred split queue too.

Reuse the second tail page's deferred_list for per memcg list since the
same THP can't be on multiple deferred split queues.

[yang.shi@linux.alibaba.com: simplify deferred split queue dereference per Kirill Tkhai]
  Link: http://lkml.kernel.org/r/1566496227-84952-5-git-send-email-yang.shi@linux.alibaba.com
Link: http://lkml.kernel.org/r/1565144277-36240-5-git-send-email-yang.shi@linux.alibaba.com
Signed-off-by: Yang Shi 
Acked-by: Kirill A. Shutemov 
Reviewed-by: Kirill Tkhai 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: "Kirill A . Shutemov" 
Cc: Hugh Dickins 
Cc: Shakeel Butt 
Cc: David Rientjes 
Cc: Qian Cai 
Cc: Vladimir Davydov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge branch 'odp_fixes' into hmm.git

2019-08-21T23:58:18+00:00

From rdma.git

Jason Gunthorpe says:

====================
This is a collection of general cleanups for ODP to clarify some of the
flows around umem creation and use of the interval tree.
====================

The branch is based on v5.3-rc5 due to dependencies, and is being taken
into hmm.git due to dependencies in the next patches.

* odp_fixes:
  RDMA/mlx5: Use odp instead of mr->umem in pagefault_mr
  RDMA/mlx5: Use ib_umem_start instead of umem.address
  RDMA/core: Make invalidate_range a device operation
  RDMA/odp: Use kvcalloc for the dma_list and page_list
  RDMA/odp: Check for overflow when computing the umem_odp end
  RDMA/odp: Provide ib_umem_odp_release() to undo the allocs
  RDMA/odp: Split creating a umem_odp from ib_umem_get
  RDMA/odp: Make the three ways to create a umem_odp clear
  RMDA/odp: Consolidate umem_odp initialization
  RDMA/odp: Make it clearer when a umem is an implicit ODP umem
  RDMA/odp: Iterate over the whole rbtree directly
  RDMA/odp: Use the common interval tree library instead of generic
  RDMA/mlx5: Fix MR npages calculation for IB_ACCESS_HUGETLB

Signed-off-by: Jason Gunthorpe

hmm: use mmu_notifier_get/put for 'struct hmm'

2019-08-20T12:35:02+00:00

This is a significant simplification, it eliminates all the remaining
'hmm' stuff in mm_struct, eliminates krefing along the critical notifier
paths, and takes away all the ugly locking and abuse of page_table_lock.

mmu_notifier_get() provides the single struct hmm per struct mm which
eliminates mm->hmm.

It also directly guarantees that no mmu_notifier op callback is callable
while concurrent free is possible, this eliminates all the krefs inside
the mmu_notifier callbacks.

The remaining krefs in the range code were overly cautious, drivers are
already not permitted to free the mirror while a range exists.

Link: https://lore.kernel.org/r/20190806231548.25242-6-jgg@ziepe.ca
Reviewed-by: Christoph Hellwig 
Reviewed-by: Ralph Campbell 
Tested-by: Ralph Campbell 
Signed-off-by: Jason Gunthorpe

mm: document zone device struct page field usage

2019-08-13T23:06:52+00:00

Patch series "mm/hmm: fixes for device private page migration", v3.

Testing the latest linux git tree turned up a few bugs with page
migration to and from ZONE_DEVICE private and anonymous pages.
Hopefully it clarifies how ZONE_DEVICE private struct page uses the same
mapping and index fields from the source anonymous page mapping.

This patch (of 3):

Struct page for ZONE_DEVICE private pages uses the page->mapping and and
page->index fields while the source anonymous pages are migrated to
device private memory.  This is so rmap_walk() can find the page when
migrating the ZONE_DEVICE private page back to system memory.
ZONE_DEVICE pmem backed fsdax pages also use the page->mapping and
page->index fields when files are mapped into a process address space.

Add comments to struct page and remove the unused "_zd_pad_1" field to
make this more clear.

Link: http://lkml.kernel.org/r/20190724232700.23327-2-rcampbell@nvidia.com
Signed-off-by: Ralph Campbell 
Reviewed-by: John Hubbard 
Cc: Matthew Wilcox 
Cc: Vlastimil Babka 
Cc: Christoph Lameter 
Cc: Dave Hansen 
Cc: Jérôme Glisse 
Cc: "Kirill A . Shutemov" 
Cc: Lai Jiangshan 
Cc: Martin Schwidefsky 
Cc: Pekka Enberg 
Cc: Randy Dunlap 
Cc: Andrey Ryabinin 
Cc: Christoph Hellwig 
Cc: Jason Gunthorpe 
Cc: Andrew Morton 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds