linux-stable.git/mm/Makefile, branch v5.7

mm: introduce Reported pages

2020-04-07T17:43:38+00:00

In order to pave the way for free page reporting in virtualized
environments we will need a way to get pages out of the free lists and
identify those pages after they have been returned.  To accomplish this,
this patch adds the concept of a Reported Buddy, which is essentially
meant to just be the Uptodate flag used in conjunction with the Buddy page
type.

To prevent the reported pages from leaking outside of the buddy lists I
added a check to clear the PageReported bit in the del_page_from_free_list
function.  As a result any reported page that is split, merged, or
allocated will have the flag cleared prior to the PageBuddy value being
cleared.

The process for reporting pages is fairly simple.  Once we free a page
that meets the minimum order for page reporting we will schedule a worker
thread to start 2s or more in the future.  That worker thread will begin
working from the lowest supported page reporting order up to MAX_ORDER - 1
pulling unreported pages from the free list and storing them in the
scatterlist.

When processing each individual free list it is necessary for the worker
thread to release the zone lock when it needs to stop and report the full
scatterlist of pages.  To reduce the work of the next iteration the worker
thread will rotate the free list so that the first unreported page in the
free list becomes the first entry in the list.

It will then call a reporting function providing information on how many
entries are in the scatterlist.  Once the function completes it will
return the pages to the free area from which they were allocated and start
over pulling more pages from the free areas until there are no longer
enough pages to report on to keep the worker busy, or we have processed as
many pages as were contained in the free area when we started processing
the list.

The worker thread will work in a round-robin fashion making its way though
each zone requesting reporting, and through each reportable free list
within that zone.  Once all free areas within the zone have been processed
it will check to see if there have been any requests for reporting while
it was processing.  If so it will reschedule the worker thread to start up
again in roughly 2s and exit.

Signed-off-by: Alexander Duyck 
Signed-off-by: Andrew Morton 
Acked-by: Mel Gorman 
Cc: Andrea Arcangeli 
Cc: Dan Williams 
Cc: Dave Hansen 
Cc: David Hildenbrand 
Cc: Konrad Rzeszutek Wilk 
Cc: Luiz Capitulino 
Cc: Matthew Wilcox 
Cc: Michael S. Tsirkin 
Cc: Michal Hocko 
Cc: Nitesh Narayan Lal 
Cc: Oscar Salvador 
Cc: Pankaj Gupta 
Cc: Paolo Bonzini 
Cc: Rik van Riel 
Cc: Vlastimil Babka 
Cc: Wei Wang 
Cc: Yang Zhang 
Cc: wei qi 
Link: http://lkml.kernel.org/r/20200211224635.29318.19750.stgit@localhost.localdomain
Signed-off-by: Linus Torvalds

mm/Makefile: disable KCSAN for kmemleak

2020-04-02T16:35:26+00:00

Kmemleak could scan task stacks while plain writes happens to those stack
variables which could results in data races.  For example, in
sys_rt_sigaction and do_sigaction(), it could have plain writes in a
32-byte size.  Since the kmemleak does not care about the actual values of
a non-pointer and all do_sigaction() call sites only copy to stack
variables, just disable KCSAN for kmemleak to avoid annotating anything
outside Kmemleak just because Kmemleak scans everything.

Suggested-by: Marco Elver 
Signed-off-by: Qian Cai 
Signed-off-by: Andrew Morton 
Acked-by: Marco Elver 
Acked-by: Catalin Marinas 
Link: http://lkml.kernel.org/r/1583263716-25150-1-git-send-email-cai@lca.pw
Signed-off-by: Linus Torvalds

mm: add generic ptdump

2020-02-04T03:05:25+00:00

Add a generic version of page table dumping that architectures can opt-in
to.

Link: http://lkml.kernel.org/r/20191218162402.45610-20-steven.price@arm.com
Signed-off-by: Steven Price 
Cc: Albert Ou 
Cc: Alexandre Ghiti 
Cc: Andy Lutomirski 
Cc: Ard Biesheuvel 
Cc: Arnd Bergmann 
Cc: Benjamin Herrenschmidt 
Cc: Borislav Petkov 
Cc: Catalin Marinas 
Cc: Christian Borntraeger 
Cc: Dave Hansen 
Cc: David S. Miller 
Cc: Heiko Carstens 
Cc: "H. Peter Anvin" 
Cc: Ingo Molnar 
Cc: James Hogan 
Cc: James Morse 
Cc: Jerome Glisse 
Cc: "Liang, Kan" 
Cc: Mark Rutland 
Cc: Michael Ellerman 
Cc: Paul Burton 
Cc: Paul Mackerras 
Cc: Paul Walmsley 
Cc: Peter Zijlstra 
Cc: Ralf Baechle 
Cc: Russell King 
Cc: Thomas Gleixner 
Cc: Vasily Gorbik 
Cc: Vineet Gupta 
Cc: Will Deacon 
Cc: Zong Li 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

kcov: ignore fault-inject and stacktrace

2020-01-31T18:30:41+00:00

Don't instrument 3 more files that contain debugging facilities and
produce large amounts of uninteresting coverage for every syscall.

The following snippets are sprinkled all over the place in kcov traces
in a debugging kernel.  We already try to disable instrumentation of
stack unwinding code and of most debug facilities.  I guess we did not
use fault-inject.c at the time, and stacktrace.c was somehow missed (or
something has changed in kernel/configs).  This change both speeds up
kcov (kernel doesn't need to store these PCs, user-space doesn't need to
process them) and frees trace buffer capacity for more useful coverage.

  should_fail
  lib/fault-inject.c:149
  fail_dump
  lib/fault-inject.c:45

  stack_trace_save
  kernel/stacktrace.c:124
  stack_trace_consume_entry
  kernel/stacktrace.c:86
  stack_trace_consume_entry
  kernel/stacktrace.c:89
  ... a hundred frames skipped ...
  stack_trace_consume_entry
  kernel/stacktrace.c:93
  stack_trace_consume_entry
  kernel/stacktrace.c:86

Link: http://lkml.kernel.org/r/20200116111449.217744-1-dvyukov@gmail.com
Signed-off-by: Dmitry Vyukov 
Reviewed-by: Andrey Konovalov 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: Add write-protect and clean utilities for address space ranges

2019-11-06T12:03:36+00:00

Add two utilities to 1) write-protect and 2) clean all ptes pointing into
a range of an address space.
The utilities are intended to aid in tracking dirty pages (either
driver-allocated system memory or pci device memory).
The write-protect utility should be used in conjunction with
page_mkwrite() and pfn_mkwrite() to trigger write page-faults on page
accesses. Typically one would want to use this on sparse accesses into
large memory regions. The clean utility should be used to utilize
hardware dirtying functionality and avoid the overhead of page-faults,
typically on large accesses into small memory regions.

Cc: Andrew Morton 
Cc: Matthew Wilcox 
Cc: Will Deacon 
Cc: Peter Zijlstra 
Cc: Rik van Riel 
Cc: Minchan Kim 
Cc: Michal Hocko 
Cc: Huang Ying 
Cc: Jérôme Glisse 
Cc: Kirill A. Shutemov 
Signed-off-by: Thomas Hellstrom 
Acked-by: Andrew Morton

mm: silence -Woverride-init/initializer-overrides

2019-09-24T22:54:10+00:00

When compiling a kernel with W=1, there are several of those warnings due
to arm64 overriding a field on purpose.  Just disable those warnings for
both GCC and Clang of this file, so it will help dig "gems" hidden in the
W=1 warnings by reducing some noises.

mm/init-mm.c:39:2: warning: initializer overrides prior initialization
of this subobject [-Winitializer-overrides]
        INIT_MM_CONTEXT(init_mm)
        ^~~~~~~~~~~~~~~~~~~~~~~~
./arch/arm64/include/asm/mmu.h:133:9: note: expanded from macro
'INIT_MM_CONTEXT'
        .pgd = init_pg_dir,
               ^~~~~~~~~~~
mm/init-mm.c:30:10: note: previous initialization is here
        .pgd            = swapper_pg_dir,
                          ^~~~~~~~~~~~~~

Note: there is a side project trying to support explicitly allowing
specific initializer overrides in Clang, but there is no guarantee it
will happen or not.

https://github.com/ClangBuiltLinux/linux/issues/639

Link: http://lkml.kernel.org/r/1566920867-27453-1-git-send-email-cai@lca.pw
Signed-off-by: Qian Cai 
Cc: Nick Desaulniers 
Cc: Masahiro Yamada 
Cc: Mark Rutland 
Cc: Arnd Bergmann 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

mm: remove quicklist page table caches

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

Patch series "mm: remove quicklist page table caches".

A while ago Nicholas proposed to remove quicklist page table caches [1].

I've rebased his patch on the curren upstream and switched ia64 and sh to
use generic versions of PTE allocation.

[1] https://lore.kernel.org/linux-mm/20190711030339.20892-1-npiggin@gmail.com

This patch (of 3):

Remove page table allocator "quicklists".  These have been around for a
long time, but have not got much traction in the last decade and are only
used on ia64 and sh architectures.

The numbers in the initial commit look interesting but probably don't
apply anymore.  If anybody wants to resurrect this it's in the git
history, but it's unhelpful to have this code and divergent allocator
behaviour for minor archs.

Also it might be better to instead make more general improvements to page
allocator if this is still so slow.

Link: http://lkml.kernel.org/r/1565250728-21721-2-git-send-email-rppt@linux.ibm.com
Signed-off-by: Nicholas Piggin 
Signed-off-by: Mike Rapoport 
Cc: Tony Luck 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

memremap: move from kernel/ to mm/

2019-08-03T14:02:01+00:00

memremap.c implements MM functionality for ZONE_DEVICE, so it really
should be in the mm/ directory, not the kernel/ one.

Link: http://lkml.kernel.org/r/20190722094143.18387-1-hch@lst.de
Signed-off-by: Christoph Hellwig 
Reviewed-by: Anshuman Khandual 
Acked-by: Dan Williams 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds

Merge tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma

2019-07-15T02:42:11+00:00

Pull HMM updates from Jason Gunthorpe:
 "Improvements and bug fixes for the hmm interface in the kernel:

   - Improve clarity, locking and APIs related to the 'hmm mirror'
     feature merged last cycle. In linux-next we now see AMDGPU and
     nouveau to be using this API.

   - Remove old or transitional hmm APIs. These are hold overs from the
     past with no users, or APIs that existed only to manage cross tree
     conflicts. There are still a few more of these cleanups that didn't
     make the merge window cut off.

   - Improve some core mm APIs:
       - export alloc_pages_vma() for driver use
       - refactor into devm_request_free_mem_region() to manage
         DEVICE_PRIVATE resource reservations
       - refactor duplicative driver code into the core dev_pagemap
         struct

   - Remove hmm wrappers of improved core mm APIs, instead have drivers
     use the simplified API directly

   - Remove DEVICE_PUBLIC

   - Simplify the kconfig flow for the hmm users and core code"

* tag 'for-linus-hmm' of git://git.kernel.org/pub/scm/linux/kernel/git/rdma/rdma: (42 commits)
  mm: don't select MIGRATE_VMA_HELPER from HMM_MIRROR
  mm: remove the HMM config option
  mm: sort out the DEVICE_PRIVATE Kconfig mess
  mm: simplify ZONE_DEVICE page private data
  mm: remove hmm_devmem_add
  mm: remove hmm_vma_alloc_locked_page
  nouveau: use devm_memremap_pages directly
  nouveau: use alloc_page_vma directly
  PCI/P2PDMA: use the dev_pagemap internal refcount
  device-dax: use the dev_pagemap internal refcount
  memremap: provide an optional internal refcount in struct dev_pagemap
  memremap: replace the altmap_valid field with a PGMAP_ALTMAP_VALID flag
  memremap: remove the data field in struct dev_pagemap
  memremap: add a migrate_to_ram method to struct dev_pagemap_ops
  memremap: lift the devmap_enable manipulation into devm_memremap_pages
  memremap: pass a struct dev_pagemap to ->kill and ->cleanup
  memremap: move dev_pagemap callbacks into a separate structure
  memremap: validate the pagemap type passed to devm_memremap_pages
  mm: factor out a devm_request_free_mem_region helper
  mm: export alloc_pages_vma
  ...

mm: consolidate the get_user_pages* implementations

2019-07-12T18:05:45+00:00

Always build mm/gup.c so that we don't have to provide separate nommu
stubs.  Also merge the get_user_pages_fast and __get_user_pages_fast stubs
when HAVE_FAST_GUP into the main implementations, which will never call
the fast path if HAVE_FAST_GUP is not set.

This also ensures the new put_user_pages* helpers are available for nommu,
as those are currently missing, which would create a problem as soon as we
actually grew users for it.

Link: http://lkml.kernel.org/r/20190625143715.1689-13-hch@lst.de
Signed-off-by: Christoph Hellwig 
Cc: Andrey Konovalov 
Cc: Benjamin Herrenschmidt 
Cc: David Miller 
Cc: James Hogan 
Cc: Jason Gunthorpe 
Cc: Khalid Aziz 
Cc: Michael Ellerman 
Cc: Nicholas Piggin 
Cc: Paul Burton 
Cc: Paul Mackerras 
Cc: Ralf Baechle 
Cc: Rich Felker 
Cc: Yoshinori Sato 
Signed-off-by: Andrew Morton 
Signed-off-by: Linus Torvalds