linux-stable.git/include/linux/mm_types.h, branch v5.9.8

mm: Introduce mm_struct.has_pinned

2020-09-27T18:21:35+00:00

(Commit message majorly collected from Jason Gunthorpe)

Reduce the chance of false positive from page_maybe_dma_pinned() by
keeping track if the mm_struct has ever been used with pin_user_pages().
This allows cases that might drive up the page ref_count to avoid any
penalty from handling dma_pinned pages.

Future work is planned, to provide a more sophisticated solution, likely
to turn it into a real counter.  For now, make it atomic_t but use it as
a boolean for simplicity.

Suggested-by: Jason Gunthorpe 
Signed-off-by: Peter Xu 
Signed-off-by: Linus Torvalds

mm: store compound_nr as well as compound_order

2020-08-15T02:56:56+00:00

Patch series "THP prep patches".

These are some generic cleanups and improvements, which I would like
merged into mmotm soon.  The first one should be a performance improvement
for all users of compound pages, and the others are aimed at getting code
to compile away when CONFIG_TRANSPARENT_HUGEPAGE is disabled (ie small
systems).  Also better documented / less confusing than the current prefix
mixture of compound, hpage and thp.

This patch (of 7):

This removes a few instructions from functions which need to know how many
pages are in a compound page.  The storage used is either page->mapping on
64-bit or page->index on 32-bit.  Both of these are fine to overlay on
tail pages.

Signed-off-by: Matthew Wilcox (Oracle) 
Signed-off-by: Andrew Morton 
Reviewed-by: William Kucharski 
Reviewed-by: Zi Yan 
Cc: David Hildenbrand 
Cc: Mike Kravetz 
Cc: "Kirill A. Shutemov" 
Link: http://lkml.kernel.org/r/20200629151959.15779-1-willy@infradead.org
Link: http://lkml.kernel.org/r/20200629151959.15779-2-willy@infradead.org
Signed-off-by: Linus Torvalds

mm: memcg/slab: allocate obj_cgroups for non-root slab pages

2020-08-07T18:33:24+00:00

Allocate and release memory to store obj_cgroup pointers for each non-root
slab page. Reuse page->mem_cgroup pointer to store a pointer to the
allocated space.

This commit temporarily increases the memory footprint of the kernel memory
accounting. To store obj_cgroup pointers we'll need a place for an
objcg_pointer for each allocated object. However, the following patches
in the series will enable sharing of slab pages between memory cgroups,
which will dramatically increase the total slab utilization. And the final
memory footprint will be significantly smaller than before.

To distinguish between obj_cgroups and memcg pointers in case when it's
not obvious which one is used (as in page_cgroup_ino()), let's always set
the lowest bit in the obj_cgroup case. The original obj_cgroups
pointer is marked to be ignored by kmemleak, which otherwise would
report a memory leak for each allocated vector.

Signed-off-by: Roman Gushchin 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Shakeel Butt 
Cc: Christoph Lameter 
Cc: Johannes Weiner 
Cc: Michal Hocko 
Cc: Tejun Heo 
Link: http://lkml.kernel.org/r/20200623174037.3951353-8-guro@fb.com
Signed-off-by: Linus Torvalds

mmap locking API: convert mmap_sem comments

2020-06-09T16:39:14+00:00

Convert comments that reference mmap_sem to reference mmap_lock instead.

[akpm@linux-foundation.org: fix up linux-next leftovers]
[akpm@linux-foundation.org: s/lockaphore/lock/, per Vlastimil]
[akpm@linux-foundation.org: more linux-next fixups, per Michel]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Daniel Jordan 
Cc: Davidlohr Bueso 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-13-walken@google.com
Signed-off-by: Linus Torvalds

mmap locking API: rename mmap_sem to mmap_lock

2020-06-09T16:39:14+00:00

Rename the mmap_sem field to mmap_lock.  Any new uses of this lock should
now go through the new mmap locking api.  The mmap_lock is still
implemented as a rwsem, though this could change in the future.

[akpm@linux-foundation.org: fix it for mm-gup-might_lock_readmmap_sem-in-get_user_pages_fast.patch]

Signed-off-by: Michel Lespinasse 
Signed-off-by: Andrew Morton 
Reviewed-by: Vlastimil Babka 
Reviewed-by: Davidlohr Bueso 
Reviewed-by: Daniel Jordan 
Cc: David Rientjes 
Cc: Hugh Dickins 
Cc: Jason Gunthorpe 
Cc: Jerome Glisse 
Cc: John Hubbard 
Cc: Laurent Dufour 
Cc: Liam Howlett 
Cc: Matthew Wilcox 
Cc: Peter Zijlstra 
Cc: Ying Han 
Link: http://lkml.kernel.org/r/20200520052908.204642-11-walken@google.com
Signed-off-by: Linus Torvalds

mm_types.h: change set_page_private to inline function

2020-06-02T17:59:08+00:00

Change it to inline function to make callers use the proper argument.  And
no need for it to be macro per Andrew's comment [1].

[1] https://lore.kernel.org/lkml/20200518221235.1fa32c38e5766113f78e3f0d@linux-foundation.org/

Signed-off-by: Guoqing Jiang 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Link: http://lkml.kernel.org/r/20200525203149.18802-1-guoqing.jiang@cloud.ionos.com
Signed-off-by: Linus Torvalds

mm: fix ambiguous comments for better code readability

2020-04-07T17:43:41+00:00

The parameter of remap_pfn_range() @pfn passed from the caller is actually
a page-frame number converted by corresponding physical address of kernel
memory, the original comment is ambiguous that may mislead the users.

Meanwhile, there is an ambiguous typo "VMM" in the comment of
vm_area_struct.  So fixing them will make the code more readable.

Signed-off-by: chenqiwu 
Signed-off-by: Andrew Morton 
Reviewed-by: Andrew Morton 
Link: http://lkml.kernel.org/r/1583026921-15279-1-git-send-email-qiwuchen55@gmail.com
Signed-off-by: Linus Torvalds

mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages

2020-04-02T16:35:27+00:00

For huge pages (and in fact, any compound page), the GUP_PIN_COUNTING_BIAS
scheme tends to overflow too easily, each tail page increments the head
page->_refcount by GUP_PIN_COUNTING_BIAS (1024).  That limits the number
of huge pages that can be pinned.

This patch removes that limitation, by using an exact form of pin counting
for compound pages of order > 1.  The "order > 1" is required because this
approach uses the 3rd struct page in the compound page, and order 1
compound pages only have two pages, so that won't work there.

A new struct page field, hpage_pinned_refcount, has been added, replacing
a padding field in the union (so no new space is used).

This enhancement also has a useful side effect: huge pages and compound
pages (of order > 1) do not suffer from the "potential false positives"
problem that is discussed in the page_dma_pinned() comment block.  That is
because these compound pages have extra space for tracking things, so they
get exact pin counts instead of overloading page->_refcount.

Documentation/core-api/pin_user_pages.rst is updated accordingly.

Suggested-by: Jan Kara 
Signed-off-by: John Hubbard 
Signed-off-by: Andrew Morton 
Reviewed-by: Jan Kara 
Acked-by: Kirill A. Shutemov 
Cc: Ira Weiny 
Cc: Jérôme Glisse 
Cc: "Matthew Wilcox (Oracle)" 
Cc: Al Viro 
Cc: Christoph Hellwig 
Cc: Dan Williams 
Cc: Dave Chinner 
Cc: Jason Gunthorpe 
Cc: Jonathan Corbet 
Cc: Michal Hocko 
Cc: Mike Kravetz 
Cc: Shuah Khan 
Cc: Vlastimil Babka 
Link: http://lkml.kernel.org/r/20200211001536.1027652-8-jhubbard@nvidia.com
Signed-off-by: Linus Torvalds

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