Commit Graph

91 Commits

Author SHA1 Message Date
Dan Williams 7cc7867fb0 mm/devm_memremap_pages: enable sub-section remap
Teach devm_memremap_pages() about the new sub-section capabilities of
arch_{add,remove}_memory().  Effectively, just replace all usage of
align_start, align_end, and align_size with res->start, res->end, and
resource_size(res).  The existing sanity check will still make sure that
the two separate remap attempts do not collide within a sub-section (2MB
on x86).

Link: http://lkml.kernel.org/r/156092355542.979959.10060071713397030576.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>	[ppc64]
Cc: Michal Hocko <mhocko@suse.com>
Cc: Toshi Kani <toshi.kani@hpe.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Jane Chu <jane.chu@oracle.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Mike Rapoport <rppt@linux.ibm.com>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Wei Yang <richardw.yang@linux.intel.com>
Cc: Jason Gunthorpe <jgg@mellanox.com>
Cc: Christoph Hellwig <hch@lst.de>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-07-18 17:08:07 -07:00
Christoph Hellwig 24917f6b10 memremap: provide an optional internal refcount in struct dev_pagemap
Provide an internal refcounting logic if no ->ref field is provided
in the pagemap passed into devm_memremap_pages so that callers don't
have to reinvent it poorly.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig 514caf23a7 memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
Add a flags field to struct dev_pagemap to replace the altmap_valid
boolean to be a little more extensible.  Also add a pgmap_altmap() helper
to find the optional altmap and clean up the code using the altmap using
it.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig 80a72d0af0 memremap: remove the data field in struct dev_pagemap
struct dev_pagemap is always embedded into a containing structure, so
there is no need to an additional private data field.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig 897e6365cd memremap: add a migrate_to_ram method to struct dev_pagemap_ops
This replaces the hacky ->fault callback, which is currently directly
called from common code through a hmm specific data structure as an
exercise in layering violations.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ralph Campbell <rcampbell@nvidia.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig f6a55e1a3f memremap: lift the devmap_enable manipulation into devm_memremap_pages
Just check if there is a ->page_free operation set and take care of the
static key enable, as well as the put using device managed resources.
Also check that a ->page_free is provided for the pgmaps types that
require it, and check for a valid type as well while we are at it.

Note that this also fixes the fact that hmm never called
dev_pagemap_put_ops and thus would leave the slow path enabled forever,
even after a device driver unload or disable.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig d8668bb045 memremap: pass a struct dev_pagemap to ->kill and ->cleanup
Passing the actual typed structure leads to more understandable code
vs just passing the ref member.

Reported-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig 1e240e8d4a memremap: move dev_pagemap callbacks into a separate structure
The dev_pagemap is a growing too many callbacks.  Move them into a
separate ops structure so that they are not duplicated for multiple
instances, and an attacker can't easily overwrite them.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Jason Gunthorpe <jgg@mellanox.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Christoph Hellwig 3ed2dcdf54 memremap: validate the pagemap type passed to devm_memremap_pages
Most pgmap types are only supported when certain config options are
enabled.  Check for a type that is valid for the current configuration
before setting up the pagemap.  For this the usage of the 0 type for
device dax gets replaced with an explicit MEMORY_DEVICE_DEVDAX type.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: Jason Gunthorpe <jgg@mellanox.com>
2019-07-02 14:32:44 -03:00
Dan Williams 50f44ee724 mm/devm_memremap_pages: fix final page put race
Logan noticed that devm_memremap_pages_release() kills the percpu_ref
drops all the page references that were acquired at init and then
immediately proceeds to unplug, arch_remove_memory(), the backing pages
for the pagemap.  If for some reason device shutdown actually collides
with a busy / elevated-ref-count page then arch_remove_memory() should
be deferred until after that reference is dropped.

As it stands the "wait for last page ref drop" happens *after*
devm_memremap_pages_release() returns, which is obviously too late and
can lead to crashes.

Fix this situation by assigning the responsibility to wait for the
percpu_ref to go idle to devm_memremap_pages() with a new ->cleanup()
callback.  Implement the new cleanup callback for all
devm_memremap_pages() users: pmem, devdax, hmm, and p2pdma.

Link: http://lkml.kernel.org/r/155727339156.292046.5432007428235387859.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 41e94a8513 ("add devm_memremap_pages")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-13 17:34:56 -10:00
Dan Williams 2e3f139e8e mm/devm_memremap_pages: introduce devm_memunmap_pages
Use the new devm_release_action() facility to allow
devm_memremap_pages_release() to be manually triggered.

Link: http://lkml.kernel.org/r/155727337088.292046.5774214552136776763.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Ira Weiny <ira.weiny@intel.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Bjorn Helgaas <bhelgaas@google.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-06-13 17:34:56 -10:00
Christoph Hellwig 640be2d1ff kernel/memremap.c: remove the unused device_private_entry_fault() export
This export has been entirely unused since it was added more than 1 1/2
years ago.

Link: http://lkml.kernel.org/r/20190429115535.12793-1-hch@lst.de
Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:51 -07:00
Michal Hocko 940519f0c8 mm, memory_hotplug: provide a more generic restrictions for memory hotplug
arch_add_memory, __add_pages take a want_memblock which controls whether
the newly added memory should get the sysfs memblock user API (e.g.
ZONE_DEVICE users do not want/need this interface).  Some callers even
want to control where do we allocate the memmap from by configuring
altmap.

Add a more generic hotplug context for arch_add_memory and __add_pages.
struct mhp_restrictions contains flags which contains additional features
to be enabled by the memory hotplug (MHP_MEMBLOCK_API currently) and
altmap for alternative memmap allocator.

This patch shouldn't introduce any functional change.

[akpm@linux-foundation.org: build fix]
Link: http://lkml.kernel.org/r/20190408082633.2864-3-osalvador@suse.de
Signed-off-by: Michal Hocko <mhocko@suse.com>
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Hildenbrand <david@redhat.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2019-05-14 09:47:49 -07:00
Dan Williams 063a7d1d36 mm/hmm: fix memremap.h, move dev_page_fault_t callback to hmm
The kbuild robot reported the following on a development branch that used
memremap.h in a new path:

   In file included from arch/m68k/include/asm/pgtable_mm.h:148:0,
                     from arch/m68k/include/asm/pgtable.h:5,
                     from include/linux/memremap.h:7,
                     from drivers//dax/bus.c:3:
    arch/m68k/include/asm/motorola_pgtable.h: In function 'pgd_offset':
 >> arch/m68k/include/asm/motorola_pgtable.h:199:11: error: dereferencing pointer to incomplete type 'const struct mm_struct'
      return mm->pgd + pgd_index(address);
               ^~

The ->page_fault() callback is specific to HMM.  Move it to 'struct
hmm_devmem' where the unusual asm/pgtable.h dependency can be contained in
include/linux/hmm.h.  Longer term refactoring this dependency out of HMM
is recommended, but in the meantime memremap.h remains generic.

Link: http://lkml.kernel.org/r/154534090899.3120190.6652620807617715272.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: 5042db43cc ("mm/ZONE_DEVICE: new type of ZONE_DEVICE memory...")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:52 -08:00
Oscar Salvador 2c2a5af6fe mm, memory_hotplug: add nid parameter to arch_remove_memory
Patch series "Do not touch pages in hot-remove path", v2.

This patchset aims for two things:

 1) A better definition about offline and hot-remove stage
 2) Solving bugs where we can access non-initialized pages
    during hot-remove operations [2] [3].

This is achieved by moving all page/zone handling to the offline
stage, so we do not need to access pages when hot-removing memory.

[1] https://patchwork.kernel.org/cover/10691415/
[2] https://patchwork.kernel.org/patch/10547445/
[3] https://www.spinics.net/lists/linux-mm/msg161316.html

This patch (of 5):

This is a preparation for the following-up patches.  The idea of passing
the nid is that it will allow us to get rid of the zone parameter
afterwards.

Link: http://lkml.kernel.org/r/20181127162005.15833-2-osalvador@suse.de
Signed-off-by: Oscar Salvador <osalvador@suse.de>
Reviewed-by: David Hildenbrand <david@redhat.com>
Reviewed-by: Pavel Tatashin <pasha.tatashin@soleen.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Jonathan Cameron <Jonathan.Cameron@huawei.com>
Cc: "Rafael J. Wysocki" <rafael@kernel.org>

Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:49 -08:00
Dan Williams 69324b8f48 mm, devm_memremap_pages: add MEMORY_DEVICE_PRIVATE support
In preparation for consolidating all ZONE_DEVICE enabling via
devm_memremap_pages(), teach it how to handle the constraints of
MEMORY_DEVICE_PRIVATE ranges.

[jglisse@redhat.com: call move_pfn_range_to_zone for MEMORY_DEVICE_PRIVATE]
Link: http://lkml.kernel.org/r/154275559036.76910.12434636179931292607.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Christoph Hellwig <hch@lst.de>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Dan Williams a95c90f1e2 mm, devm_memremap_pages: fix shutdown handling
The last step before devm_memremap_pages() returns success is to allocate
a release action, devm_memremap_pages_release(), to tear the entire setup
down.  However, the result from devm_add_action() is not checked.

Checking the error from devm_add_action() is not enough.  The api
currently relies on the fact that the percpu_ref it is using is killed by
the time the devm_memremap_pages_release() is run.  Rather than continue
this awkward situation, offload the responsibility of killing the
percpu_ref to devm_memremap_pages_release() directly.  This allows
devm_memremap_pages() to do the right thing relative to init failures and
shutdown.

Without this change we could fail to register the teardown of
devm_memremap_pages().  The likelihood of hitting this failure is tiny as
small memory allocations almost always succeed.  However, the impact of
the failure is large given any future reconfiguration, or disable/enable,
of an nvdimm namespace will fail forever as subsequent calls to
devm_memremap_pages() will fail to setup the pgmap_radix since there will
be stale entries for the physical address range.

An argument could be made to require that the ->kill() operation be set in
the @pgmap arg rather than passed in separately.  However, it helps code
readability, tracking the lifetime of a given instance, to be able to grep
the kill routine directly at the devm_memremap_pages() call site.

Link: http://lkml.kernel.org/r/154275558526.76910.7535251937849268605.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Fixes: e8d5134833 ("memremap: change devm_memremap_pages interface...")
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Reported-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Dan Williams 06489cfbd9 mm, devm_memremap_pages: kill mapping "System RAM" support
Given the fact that devm_memremap_pages() requires a percpu_ref that is
torn down by devm_memremap_pages_release() the current support for mapping
RAM is broken.

Support for remapping "System RAM" has been broken since the beginning and
there is no existing user of this this code path, so just kill the support
and make it an explicit error.

This cleanup also simplifies a follow-on patch to fix the error path when
setting a devm release action for devm_memremap_pages_release() fails.

Link: http://lkml.kernel.org/r/154275557997.76910.14689813630968180480.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: "Jérôme Glisse" <jglisse@redhat.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Dan Williams 808153e118 mm, devm_memremap_pages: mark devm_memremap_pages() EXPORT_SYMBOL_GPL
devm_memremap_pages() is a facility that can create struct page entries
for any arbitrary range and give drivers the ability to subvert core
aspects of page management.

Specifically the facility is tightly integrated with the kernel's memory
hotplug functionality.  It injects an altmap argument deep into the
architecture specific vmemmap implementation to allow allocating from
specific reserved pages, and it has Linux specific assumptions about page
structure reference counting relative to get_user_pages() and
get_user_pages_fast().  It was an oversight and a mistake that this was
not marked EXPORT_SYMBOL_GPL from the outset.

Again, devm_memremap_pagex() exposes and relies upon core kernel internal
assumptions and will continue to evolve along with 'struct page', memory
hotplug, and support for new memory types / topologies.  Only an in-kernel
GPL-only driver is expected to keep up with this ongoing evolution.  This
interface, and functionality derived from this interface, is not suitable
for kernel-external drivers.

Link: http://lkml.kernel.org/r/154275557457.76910.16923571232582744134.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Acked-by: Michal Hocko <mhocko@suse.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Logan Gunthorpe <logang@deltatee.com>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-12-28 12:11:47 -08:00
Linus Torvalds dad4f140ed Merge branch 'xarray' of git://git.infradead.org/users/willy/linux-dax
Pull XArray conversion from Matthew Wilcox:
 "The XArray provides an improved interface to the radix tree data
  structure, providing locking as part of the API, specifying GFP flags
  at allocation time, eliminating preloading, less re-walking the tree,
  more efficient iterations and not exposing RCU-protected pointers to
  its users.

  This patch set

   1. Introduces the XArray implementation

   2. Converts the pagecache to use it

   3. Converts memremap to use it

  The page cache is the most complex and important user of the radix
  tree, so converting it was most important. Converting the memremap
  code removes the only other user of the multiorder code, which allows
  us to remove the radix tree code that supported it.

  I have 40+ followup patches to convert many other users of the radix
  tree over to the XArray, but I'd like to get this part in first. The
  other conversions haven't been in linux-next and aren't suitable for
  applying yet, but you can see them in the xarray-conv branch if you're
  interested"

* 'xarray' of git://git.infradead.org/users/willy/linux-dax: (90 commits)
  radix tree: Remove multiorder support
  radix tree test: Convert multiorder tests to XArray
  radix tree tests: Convert item_delete_rcu to XArray
  radix tree tests: Convert item_kill_tree to XArray
  radix tree tests: Move item_insert_order
  radix tree test suite: Remove multiorder benchmarking
  radix tree test suite: Remove __item_insert
  memremap: Convert to XArray
  xarray: Add range store functionality
  xarray: Move multiorder_check to in-kernel tests
  xarray: Move multiorder_shrink to kernel tests
  xarray: Move multiorder account test in-kernel
  radix tree test suite: Convert iteration test to XArray
  radix tree test suite: Convert tag_tagged_items to XArray
  radix tree: Remove radix_tree_clear_tags
  radix tree: Remove radix_tree_maybe_preload_order
  radix tree: Remove split/join code
  radix tree: Remove radix_tree_update_node_t
  page cache: Finish XArray conversion
  dax: Convert page fault handlers to XArray
  ...
2018-10-28 11:35:40 -07:00
Alexander Duyck 966cf44f63 mm: defer ZONE_DEVICE page initialization to the point where we init pgmap
The ZONE_DEVICE pages were being initialized in two locations.  One was
with the memory_hotplug lock held and another was outside of that lock.
The problem with this is that it was nearly doubling the memory
initialization time.  Instead of doing this twice, once while holding a
global lock and once without, I am opting to defer the initialization to
the one outside of the lock.  This allows us to avoid serializing the
overhead for memory init and we can instead focus on per-node init times.

One issue I encountered is that devm_memremap_pages and
hmm_devmmem_pages_create were initializing only the pgmap field the same
way.  One wasn't initializing hmm_data, and the other was initializing it
to a poison value.  Since this is something that is exposed to the driver
in the case of hmm I am opting for a third option and just initializing
hmm_data to 0 since this is going to be exposed to unknown third party
drivers.

[alexander.h.duyck@linux.intel.com: fix reference count for pgmap in devm_memremap_pages]
  Link: http://lkml.kernel.org/r/20181008233404.1909.37302.stgit@localhost.localdomain
Link: http://lkml.kernel.org/r/20180925202053.3576.66039.stgit@localhost.localdomain
Signed-off-by: Alexander Duyck <alexander.h.duyck@linux.intel.com>
Reviewed-by: Pavel Tatashin <pavel.tatashin@microsoft.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Hansen <dave.hansen@intel.com>
Cc: Michal Hocko <mhocko@suse.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-10-26 16:26:34 -07:00
Matthew Wilcox bcfa4b7211 memremap: Convert to XArray
Use the new xa_store_range function instead of the radix tree.

Signed-off-by: Matthew Wilcox <willy@infradead.org>
2018-10-21 10:46:47 -04:00
Linus Torvalds 2923b27e54 libnvdimm-for-4.19_dax-memory-failure
* memory_failure() gets confused by dev_pagemap backed mappings. The
   recovery code has specific enabling for several possible page states
   that needs new enabling to handle poison in dax mappings. Teach
   memory_failure() about ZONE_DEVICE pages.
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Merge tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm

Pull libnvdimm memory-failure update from Dave Jiang:
 "As it stands, memory_failure() gets thoroughly confused by dev_pagemap
  backed mappings. The recovery code has specific enabling for several
  possible page states and needs new enabling to handle poison in dax
  mappings.

  In order to support reliable reverse mapping of user space addresses:

   1/ Add new locking in the memory_failure() rmap path to prevent races
      that would typically be handled by the page lock.

   2/ Since dev_pagemap pages are hidden from the page allocator and the
      "compound page" accounting machinery, add a mechanism to determine
      the size of the mapping that encompasses a given poisoned pfn.

   3/ Given pmem errors can be repaired, change the speculatively
      accessed poison protection, mce_unmap_kpfn(), to be reversible and
      otherwise allow ongoing access from the kernel.

  A side effect of this enabling is that MADV_HWPOISON becomes usable
  for dax mappings, however the primary motivation is to allow the
  system to survive userspace consumption of hardware-poison via dax.
  Specifically the current behavior is:

     mce: Uncorrected hardware memory error in user-access at af34214200
     {1}[Hardware Error]: It has been corrected by h/w and requires no further action
     mce: [Hardware Error]: Machine check events logged
     {1}[Hardware Error]: event severity: corrected
     Memory failure: 0xaf34214: reserved kernel page still referenced by 1 users
     [..]
     Memory failure: 0xaf34214: recovery action for reserved kernel page: Failed
     mce: Memory error not recovered
     <reboot>

  ...and with these changes:

     Injecting memory failure for pfn 0x20cb00 at process virtual address 0x7f763dd00000
     Memory failure: 0x20cb00: Killing dax-pmd:5421 due to hardware memory corruption
     Memory failure: 0x20cb00: recovery action for dax page: Recovered

  Given all the cross dependencies I propose taking this through
  nvdimm.git with acks from Naoya, x86/core, x86/RAS, and of course dax
  folks"

* tag 'libnvdimm-for-4.19_dax-memory-failure' of gitolite.kernel.org:pub/scm/linux/kernel/git/nvdimm/nvdimm:
  libnvdimm, pmem: Restore page attributes when clearing errors
  x86/memory_failure: Introduce {set, clear}_mce_nospec()
  x86/mm/pat: Prepare {reserve, free}_memtype() for "decoy" addresses
  mm, memory_failure: Teach memory_failure() about dev_pagemap pages
  filesystem-dax: Introduce dax_lock_mapping_entry()
  mm, memory_failure: Collect mapping size in collect_procs()
  mm, madvise_inject_error: Let memory_failure() optionally take a page reference
  mm, dev_pagemap: Do not clear ->mapping on final put
  mm, madvise_inject_error: Disable MADV_SOFT_OFFLINE for ZONE_DEVICE pages
  filesystem-dax: Set page->index
  device-dax: Set page->index
  device-dax: Enable page_mapping()
  device-dax: Convert to vmf_insert_mixed and vm_fault_t
2018-08-25 18:43:59 -07:00
Souptick Joarder 2b74030354 mm: Change return type int to vm_fault_t for fault handlers
Use new return type vm_fault_t for fault handler.  For now, this is just
documenting that the function returns a VM_FAULT value rather than an
errno.  Once all instances are converted, vm_fault_t will become a
distinct type.

Ref-> commit 1c8f422059 ("mm: change return type to vm_fault_t")

The aim is to change the return type of finish_fault() and
handle_mm_fault() to vm_fault_t type.  As part of that clean up return
type of all other recursively called functions have been changed to
vm_fault_t type.

The places from where handle_mm_fault() is getting invoked will be
change to vm_fault_t type but in a separate patch.

vmf_error() is the newly introduce inline function in 4.17-rc6.

[akpm@linux-foundation.org: don't shadow outer local `ret' in __do_huge_pmd_anonymous_page()]
Link: http://lkml.kernel.org/r/20180604171727.GA20279@jordon-HP-15-Notebook-PC
Signed-off-by: Souptick Joarder <jrdr.linux@gmail.com>
Reviewed-by: Matthew Wilcox <mawilcox@microsoft.com>
Reviewed-by: Andrew Morton <akpm@linux-foundation.org>
Cc: Matthew Wilcox <willy@infradead.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-23 18:48:44 -07:00
Andrey Ryabinin 0207df4fa1 kernel/memremap, kasan: make ZONE_DEVICE with work with KASAN
KASAN learns about hotadded memory via the memory hotplug notifier.
devm_memremap_pages() intentionally skips calling memory hotplug
notifiers.  So KASAN doesn't know anything about new memory added by
devm_memremap_pages().  This causes a crash when KASAN tries to access
non-existent shadow memory:

 BUG: unable to handle kernel paging request at ffffed0078000000
 RIP: 0010:check_memory_region+0x82/0x1e0
 Call Trace:
  memcpy+0x1f/0x50
  pmem_do_bvec+0x163/0x720
  pmem_make_request+0x305/0xac0
  generic_make_request+0x54f/0xcf0
  submit_bio+0x9c/0x370
  submit_bh_wbc+0x4c7/0x700
  block_read_full_page+0x5ef/0x870
  do_read_cache_page+0x2b8/0xb30
  read_dev_sector+0xbd/0x3f0
  read_lba.isra.0+0x277/0x670
  efi_partition+0x41a/0x18f0
  check_partition+0x30d/0x5e9
  rescan_partitions+0x18c/0x840
  __blkdev_get+0x859/0x1060
  blkdev_get+0x23f/0x810
  __device_add_disk+0x9c8/0xde0
  pmem_attach_disk+0x9a8/0xf50
  nvdimm_bus_probe+0xf3/0x3c0
  driver_probe_device+0x493/0xbd0
  bus_for_each_drv+0x118/0x1b0
  __device_attach+0x1cd/0x2b0
  bus_probe_device+0x1ac/0x260
  device_add+0x90d/0x1380
  nd_async_device_register+0xe/0x50
  async_run_entry_fn+0xc3/0x5d0
  process_one_work+0xa0a/0x1810
  worker_thread+0x87/0xe80
  kthread+0x2d7/0x390
  ret_from_fork+0x3a/0x50

Add kasan_add_zero_shadow()/kasan_remove_zero_shadow() - post mm_init()
interface to map/unmap kasan_zero_page at requested virtual addresses.
And use it to add/remove the shadow memory for hotplugged/unplugged
device memory.

Link: http://lkml.kernel.org/r/20180629164932.740-1-aryabinin@virtuozzo.com
Fixes: 41e94a8513 ("add devm_memremap_pages")
Signed-off-by: Andrey Ryabinin <aryabinin@virtuozzo.com>
Reported-by: Dave Chinner <david@fromorbit.com>
Reviewed-by: Dan Williams <dan.j.williams@intel.com>
Tested-by: Dan Williams <dan.j.williams@intel.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Cc: Alexander Potapenko <glider@google.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-08-17 16:20:30 -07:00
Dan Williams 31c5bda3a6 mm: fix exports that inadvertently make put_page() EXPORT_SYMBOL_GPL
Commit e763848843 ("mm: introduce MEMORY_DEVICE_FS_DAX and
CONFIG_DEV_PAGEMAP_OPS") added two EXPORT_SYMBOL_GPL() symbols, but
these symbols are required by the inlined put_page(), thus accidentally
making put_page() a GPL export only.  This breaks OpenAFS (at least).

Mark them EXPORT_SYMBOL() instead.

Link: http://lkml.kernel.org/r/153128611970.2928.11310692420711601254.stgit@dwillia2-desk3.amr.corp.intel.com
Fixes: e763848843 ("mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Joe Gorse <jhgorse@gmail.com>
Reported-by: John Hubbard <jhubbard@nvidia.com>
Tested-by: Joe Gorse <jhgorse@gmail.com>
Tested-by: John Hubbard <jhubbard@nvidia.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Mark Vitale <mvitale@sinenomine.net>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-26 19:38:03 -07:00
Dave Jiang 15d36fecd0 mm: disallow mappings that conflict for devm_memremap_pages()
When pmem namespaces created are smaller than section size, this can
cause an issue during removal and gpf was observed:

  general protection fault: 0000 1 SMP PTI
  CPU: 36 PID: 3941 Comm: ndctl Tainted: G W 4.14.28-1.el7uek.x86_64 #2
  task: ffff88acda150000 task.stack: ffffc900233a4000
  RIP: 0010:__put_page+0x56/0x79
  Call Trace:
    devm_memremap_pages_release+0x155/0x23a
    release_nodes+0x21e/0x260
    devres_release_all+0x3c/0x48
    device_release_driver_internal+0x15c/0x207
    device_release_driver+0x12/0x14
    unbind_store+0xba/0xd8
    drv_attr_store+0x27/0x31
    sysfs_kf_write+0x3f/0x46
    kernfs_fop_write+0x10f/0x18b
    __vfs_write+0x3a/0x16d
    vfs_write+0xb2/0x1a1
    SyS_write+0x55/0xb9
    do_syscall_64+0x79/0x1ae
    entry_SYSCALL_64_after_hwframe+0x3d/0x0

Add code to check whether we have a mapping already in the same section
and prevent additional mappings from being created if that is the case.

Link: http://lkml.kernel.org/r/152909478401.50143.312364396244072931.stgit@djiang5-desk3.ch.intel.com
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Robert Elliott <elliott@hpe.com>
Cc: Jeff Moyer <jmoyer@redhat.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: <stable@vger.kernel.org>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2018-07-26 19:38:03 -07:00
Dan Williams 2fa147bdbf mm, dev_pagemap: Do not clear ->mapping on final put
MEMORY_DEVICE_FS_DAX relies on typical page semantics whereby ->mapping
is only ever cleared by truncation, not final put.

Without this fix dax pages may forget their mapping association at the
end of every page pin event.

Move this atypical behavior that HMM wants into the HMM ->page_free()
callback.

Cc: <stable@vger.kernel.org>
Cc: Jan Kara <jack@suse.cz>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Fixes: d2c997c0f1 ("fs, dax: use page->mapping...")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Acked-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Dave Jiang <dave.jiang@intel.com>
2018-07-23 10:37:39 -07:00
Dan Williams e763848843 mm: introduce MEMORY_DEVICE_FS_DAX and CONFIG_DEV_PAGEMAP_OPS
In preparation for fixing dax-dma-vs-unmap issues, filesystems need to
be able to rely on the fact that they will get wakeups on dev_pagemap
page-idle events. Introduce MEMORY_DEVICE_FS_DAX and
generic_dax_page_free() as common indicator / infrastructure for dax
filesytems to require. With this change there are no users of the
MEMORY_DEVICE_HOST designation, so remove it.

The HMM sub-system extended dev_pagemap to arrange a callback when a
dev_pagemap managed page is freed. Since a dev_pagemap page is free /
idle when its reference count is 1 it requires an additional branch to
check the page-type at put_page() time. Given put_page() is a hot-path
we do not want to incur that check if HMM is not in use, so a static
branch is used to avoid that overhead when not necessary.

Now, the FS_DAX implementation wants to reuse this mechanism for
receiving dev_pagemap ->page_free() callbacks. Rework the HMM-specific
static-key into a generic mechanism that either HMM or FS_DAX code paths
can enable.

For ARCH=um builds, and any other arch that lacks ZONE_DEVICE support,
care must be taken to compile out the DEV_PAGEMAP_OPS infrastructure.
However, we still need to support FS_DAX in the FS_DAX_LIMITED case
implemented by the s390/dcssblk driver.

Cc: Martin Schwidefsky <schwidefsky@de.ibm.com>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Michal Hocko <mhocko@suse.com>
Reported-by: kbuild test robot <lkp@intel.com>
Reported-by: Thomas Meyer <thomas@m3y3r.de>
Reported-by: Dave Jiang <dave.jiang@intel.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Reviewed-by: Jan Kara <jack@suse.cz>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-05-22 06:59:39 -07:00
Dan Williams 5981690ddb memremap: split devm_memremap_pages() and memremap() infrastructure
Currently, kernel/memremap.c contains generic code for supporting
memremap() (CONFIG_HAS_IOMEM) and devm_memremap_pages()
(CONFIG_ZONE_DEVICE). This causes ongoing build maintenance problems as
additions to memremap.c, especially for the ZONE_DEVICE case, need to be
careful about being placed in ifdef guards. Remove the need for these
ifdef guards by moving the ZONE_DEVICE support functions to their own
compilation unit.

Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Jan Kara <jack@suse.cz>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-05-15 23:08:33 -07:00
Oliver O'Halloran 167f5594b5 kernel/memremap: Remove stale devres_free() call
devm_memremap_pages() was re-worked in e8d5134833 "memremap: change
devm_memremap_pages interface to use struct dev_pagemap" to take a
caller allocated struct dev_pagemap as a function parameter. A call to
devres_free() was left in the error cleanup path which results in a
kernel panic if the remap fails for some reason. Remove it to fix the
panic and let devm_memremap_pages() fail gracefully.

Fixes: e8d5134833 ("memremap: change devm_memremap_pages interface...")
Signed-off-by: Oliver O'Halloran <oohall@gmail.com>
Reviewed-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-03-06 10:58:54 -08:00
Dan Williams 949b93250a memremap: fix softlockup reports at teardown
The cond_resched() currently in the setup path needs to be duplicated in
the teardown path. Rather than require each instance of
for_each_device_pfn() to open code the same sequence, embed it in the
helper.

Link: https://github.com/intel/ixpdimm_sw/issues/11
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Christoph Hellwig <hch@lst.de>
Cc: <stable@vger.kernel.org>
Fixes: 7138970383 ("mm, zone_device: Replace {get, put}_zone_device_page()...")
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-03-02 19:34:50 -08:00
Jan H. Schönherr 77dd66a3c6 mm: Fix devm_memremap_pages() collision handling
If devm_memremap_pages() detects a collision while adding entries
to the radix-tree, we call pgmap_radix_release(). Unfortunately,
the function removes *all* entries for the range -- including the
entries that caused the collision in the first place.

Modify pgmap_radix_release() to take an additional argument to
indicate where to stop, so that only newly added entries are removed
from the tree.

Cc: <stable@vger.kernel.org>
Fixes: 9476df7d80 ("mm: introduce find_dev_pagemap()")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-19 16:29:56 -08:00
Jan H. Schönherr 10a0cd6e49 mm: Fix memory size alignment in devm_memremap_pages_release()
The functions devm_memremap_pages() and devm_memremap_pages_release() use
different ways to calculate the section-aligned amount of memory. The
latter function may use an incorrect size if the memory region is small
but straddles a section border.

Use the same code for both.

Cc: <stable@vger.kernel.org>
Fixes: 5f29a77cd9 ("mm: fix mixed zone detection in devm_memremap_pages")
Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-19 16:29:48 -08:00
Christoph Hellwig e697c5b90e memremap: merge find_dev_pagemap into get_dev_pagemap
There is only one caller of the trivial function find_dev_pagemap left,
so just merge it into the caller.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig e8d5134833 memremap: change devm_memremap_pages interface to use struct dev_pagemap
This new interface is similar to how struct device (and many others)
work. The caller initializes a 'struct dev_pagemap' as required
and calls 'devm_memremap_pages'. This allows the pagemap structure to
be embedded in another structure and thus container_of can be used. In
this way application specific members can be stored in a containing
struct.

This will be used by the P2P infrastructure and HMM could probably
be cleaned up to use it as well (instead of having it's own, similar
'hmm_devmem_pages_create' function).

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Logan Gunthorpe e7744aa25c memremap: drop private struct page_map
'struct page_map' is a private structure of 'struct dev_pagemap' but the
latter replicates all the same fields as the former so there isn't much
value in it. Thus drop it in favour of a completely public struct.

This is a clean up in preperation for a more generally useful
'devm_memeremap_pages' interface.

Signed-off-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig 7003e3b1f6 memremap: simplify duplicate region handling in devm_memremap_pages
__radix_tree_insert already checks for duplicates and returns -EEXIST in
that case, so remove the duplicate (and racy) duplicates check.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig 0628b8c650 memremap: remove to_vmem_altmap
All callers are gone now.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig 832d7aa051 mm: optimize dev_pagemap reference counting around get_dev_pagemap
Change the calling convention so that get_dev_pagemap always consumes the
previous reference instead of doing this using an explicit earlier call to
put_dev_pagemap in the callers.

The callers will still need to put the final reference after finishing the
loop over the pages.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig 0822acb86c mm: move get_dev_pagemap out of line
This is a pretty big function, which should be out of line in general,
and a no-op stub if CONFIG_ZONE_DEVICЕ is not set.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Reviewed-by: Logan Gunthorpe <logang@deltatee.com>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig a99583e780 mm: pass the vmem_altmap to memmap_init_zone
Pass the vmem_altmap two levels down instead of needing a lookup.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig da024512a1 mm: pass the vmem_altmap to arch_remove_memory and __remove_pages
We can just pass this on instead of having to do a radix tree lookup
without proper locking 2 levels into the callchain.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Christoph Hellwig 24e6d5a59a mm: pass the vmem_altmap to arch_add_memory and __add_pages
We can just pass this on instead of having to do a radix tree lookup
without proper locking 2 levels into the callchain.

Signed-off-by: Christoph Hellwig <hch@lst.de>
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
2018-01-08 11:46:23 -08:00
Michal Hocko 1fdcce6e16 memremap: add scheduling point to devm_memremap_pages
devm_memremap_pages is initializing struct pages in for_each_device_pfn
and that can take quite some time.  We have even seen a soft lockup
triggering on a non preemptive kernel

  NMI watchdog: BUG: soft lockup - CPU#61 stuck for 22s! [kworker/u641:11:1808]
  [...]
  RIP: 0010:[<ffffffff8118b6b7>]  [<ffffffff8118b6b7>] devm_memremap_pages+0x327/0x430
  [...]
  Call Trace:
    pmem_attach_disk+0x2fd/0x3f0 [nd_pmem]
    nvdimm_bus_probe+0x64/0x110 [libnvdimm]
    driver_probe_device+0x1f7/0x420
    bus_for_each_drv+0x52/0x80
    __device_attach+0xb0/0x130
    bus_probe_device+0x87/0xa0
    device_add+0x3fc/0x5f0
    nd_async_device_register+0xe/0x40 [libnvdimm]
    async_run_entry_fn+0x43/0x150
    process_one_work+0x14e/0x410
    worker_thread+0x116/0x490
    kthread+0xc7/0xe0
    ret_from_fork+0x3f/0x70

fix this by adding cond_resched every 1024 pages.

Link: http://lkml.kernel.org/r/20170918121410.24466-4-mhocko@kernel.org
Signed-off-by: Michal Hocko <mhocko@suse.com>
Reported-by: Johannes Thumshirn <jthumshirn@suse.de>
Tested-by: Johannes Thumshirn <jthumshirn@suse.de>
Cc: Dan Williams <dan.j.williams@gmail.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-10-03 17:54:25 -07:00
Jérôme Glisse df6ad69838 mm/device-public-memory: device memory cache coherent with CPU
Platform with advance system bus (like CAPI or CCIX) allow device memory
to be accessible from CPU in a cache coherent fashion.  Add a new type of
ZONE_DEVICE to represent such memory.  The use case are the same as for
the un-addressable device memory but without all the corners cases.

Link: http://lkml.kernel.org/r/20170817000548.32038-19-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:46 -07:00
Jérôme Glisse c733a82874 mm/memcontrol: support MEMORY_DEVICE_PRIVATE
HMM pages (private or public device pages) are ZONE_DEVICE page and thus
need special handling when it comes to lru or refcount.  This patch make
sure that memcontrol properly handle those when it face them.  Those pages
are use like regular pages in a process address space either as anonymous
page or as file back page.  So from memcg point of view we want to handle
them like regular page for now at least.

Link: http://lkml.kernel.org/r/20170817000548.32038-11-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Acked-by: Balbir Singh <bsingharora@gmail.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:46 -07:00
Jérôme Glisse 7b2d55d2c8 mm/ZONE_DEVICE: special case put_page() for device private pages
A ZONE_DEVICE page that reach a refcount of 1 is free ie no longer have
any user.  For device private pages this is important to catch and thus we
need to special case put_page() for this.

Link: http://lkml.kernel.org/r/20170817000548.32038-9-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:46 -07:00
Jérôme Glisse 5042db43cc mm/ZONE_DEVICE: new type of ZONE_DEVICE for unaddressable memory
HMM (heterogeneous memory management) need struct page to support
migration from system main memory to device memory.  Reasons for HMM and
migration to device memory is explained with HMM core patch.

This patch deals with device memory that is un-addressable memory (ie CPU
can not access it).  Hence we do not want those struct page to be manage
like regular memory.  That is why we extend ZONE_DEVICE to support
different types of memory.

A persistent memory type is define for existing user of ZONE_DEVICE and a
new device un-addressable type is added for the un-addressable memory
type.  There is a clear separation between what is expected from each
memory type and existing user of ZONE_DEVICE are un-affected by new
requirement and new use of the un-addressable type.  All specific code
path are protect with test against the memory type.

Because memory is un-addressable we use a new special swap type for when a
page is migrated to device memory (this reduces the number of maximum swap
file).

The main two additions beside memory type to ZONE_DEVICE is two callbacks.
First one, page_free() is call whenever page refcount reach 1 (which
means the page is free as ZONE_DEVICE page never reach a refcount of 0).
This allow device driver to manage its memory and associated struct page.

The second callback page_fault() happens when there is a CPU access to an
address that is back by a device page (which are un-addressable by the
CPU).  This callback is responsible to migrate the page back to system
main memory.  Device driver can not block migration back to system memory,
HMM make sure that such page can not be pin into device memory.

If device is in some error condition and can not migrate memory back then
a CPU page fault to device memory should end with SIGBUS.

[arnd@arndb.de: fix warning]
  Link: http://lkml.kernel.org/r/20170823133213.712917-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20170817000548.32038-8-jglisse@redhat.com
Signed-off-by: Jérôme Glisse <jglisse@redhat.com>
Signed-off-by: Arnd Bergmann <arnd@arndb.de>
Acked-by: Dan Williams <dan.j.williams@intel.com>
Cc: Ross Zwisler <ross.zwisler@linux.intel.com>
Cc: Aneesh Kumar <aneesh.kumar@linux.vnet.ibm.com>
Cc: Balbir Singh <bsingharora@gmail.com>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: David Nellans <dnellans@nvidia.com>
Cc: Evgeny Baskakov <ebaskakov@nvidia.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: John Hubbard <jhubbard@nvidia.com>
Cc: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Mark Hairgrove <mhairgrove@nvidia.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Paul E. McKenney <paulmck@linux.vnet.ibm.com>
Cc: Sherry Cheung <SCheung@nvidia.com>
Cc: Subhash Gutti <sgutti@nvidia.com>
Cc: Vladimir Davydov <vdavydov.dev@gmail.com>
Cc: Bob Liu <liubo95@huawei.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-08 18:26:46 -07:00
Dan Williams ab1b597ee0 mm, devm_memremap_pages: use multi-order radix for ZONE_DEVICE lookups
devm_memremap_pages() records mapped ranges in pgmap_radix with an entry
per section's worth of memory (128MB).  The key for each of those
entries is a section number.

This leads to false positives when devm_memremap_pages() is passed a
section-unaligned range as lookups in the misalignment fail to return
NULL.  We can close this hole by using the pfn as the key for entries in
the tree.  The number of entries required to describe a remapped range
is reduced by leveraging multi-order entries.

In practice this approach usually yields just one entry in the tree if
the size and starting address are of the same power-of-2 alignment.
Previously we always needed nr_entries = mapping_size / 128MB.

Link: https://lists.01.org/pipermail/linux-nvdimm/2016-August/006666.html
Link: http://lkml.kernel.org/r/150215410565.39310.13767886055248249438.stgit@dwillia2-desk3.amr.corp.intel.com
Signed-off-by: Dan Williams <dan.j.williams@intel.com>
Reported-by: Toshi Kani <toshi.kani@hpe.com>
Cc: Matthew Wilcox <mawilcox@microsoft.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2017-09-06 17:27:29 -07:00