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  1. 04 6月, 2020 5 次提交
    • M
      mm: free_area_init: use maximal zone PFNs rather than zone sizes · fa3354e4
      由 Mike Rapoport 提交于 
      Currently, architectures that use free_area_init() to initialize memory
map and node and zone structures need to calculate zone and hole sizes.
We can use free_area_init_nodes() instead and let it detect the zone
boundaries while the architectures will only have to supply the possible
limits for the zones.
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
Reviewed-by: NBaoquan He <bhe@redhat.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200412194859.12663-5-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      fa3354e4
    • M
      mm: remove CONFIG_HAVE_MEMBLOCK_NODE_MAP option · 3f08a302
      由 Mike Rapoport 提交于 
      CONFIG_HAVE_MEMBLOCK_NODE_MAP is used to differentiate initialization of
nodes and zones structures between the systems that have region to node
mapping in memblock and those that don't.

Currently all the NUMA architectures enable this option and for the
non-NUMA systems we can presume that all the memory belongs to node 0 and
therefore the compile time configuration option is not required.

The remaining few architectures that use DISCONTIGMEM without NUMA are
easily updated to use memblock_add_node() instead of memblock_add() and
thus have proper correspondence of memblock regions to NUMA nodes.

Still, free_area_init_node() must have a backward compatible version
because its semantics with and without CONFIG_HAVE_MEMBLOCK_NODE_MAP is
different.  Once all the architectures will use the new semantics, the
entire compatibility layer can be dropped.

To avoid addition of extra run time memory to store node id for
architectures that keep memblock but have only a single node, the node id
field of the memblock_region is guarded by CONFIG_NEED_MULTIPLE_NODES and
the corresponding accessors presume that in those cases it is always 0.
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
Acked-by: Catalin Marinas <catalin.marinas@arm.com>	[arm64]
Cc: Baoquan He <bhe@redhat.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200412194859.12663-4-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3f08a302
    • M
      mm: make early_pfn_to_nid() and related defintions close to each other · 6f24fbd3
      由 Mike Rapoport 提交于 
      early_pfn_to_nid() and its helper __early_pfn_to_nid() are spread around
include/linux/mm.h, include/linux/mmzone.h and mm/page_alloc.c.

Drop unused stub for __early_pfn_to_nid() and move its actual generic
implementation close to its users.
Signed-off-by: NMike Rapoport <rppt@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: Hoan Tran <hoan@os.amperecomputing.com>	[arm64]
Reviewed-by: NBaoquan He <bhe@redhat.com>
Cc: Brian Cain <bcain@codeaurora.org>
Cc: Catalin Marinas <catalin.marinas@arm.com>
Cc: "David S. Miller" <davem@davemloft.net>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Greentime Hu <green.hu@gmail.com>
Cc: Greg Ungerer <gerg@linux-m68k.org>
Cc: Guan Xuetao <gxt@pku.edu.cn>
Cc: Guo Ren <guoren@kernel.org>
Cc: Heiko Carstens <heiko.carstens@de.ibm.com>
Cc: Helge Deller <deller@gmx.de>
Cc: "James E.J. Bottomley" <James.Bottomley@HansenPartnership.com>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Ley Foon Tan <ley.foon.tan@intel.com>
Cc: Mark Salter <msalter@redhat.com>
Cc: Matt Turner <mattst88@gmail.com>
Cc: Max Filippov <jcmvbkbc@gmail.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Michal Simek <monstr@monstr.eu>
Cc: Nick Hu <nickhu@andestech.com>
Cc: Paul Walmsley <paul.walmsley@sifive.com>
Cc: Richard Weinberger <richard@nod.at>
Cc: Rich Felker <dalias@libc.org>
Cc: Russell King <linux@armlinux.org.uk>
Cc: Stafford Horne <shorne@gmail.com>
Cc: Thomas Bogendoerfer <tsbogend@alpha.franken.de>
Cc: Tony Luck <tony.luck@intel.com>
Cc: Vineet Gupta <vgupta@synopsys.com>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Link: http://lkml.kernel.org/r/20200412194859.12663-3-rppt@kernel.orgSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      6f24fbd3
    • J
      mm/gup: introduce pin_user_pages_fast_only() · 104acc32
      由 John Hubbard 提交于 
      This is the FOLL_PIN equivalent of __get_user_pages_fast(), except with a
more descriptive name, and gup_flags instead of a boolean "write" in the
argument list.
Signed-off-by: NJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: "Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://lkml.kernel.org/r/20200519002124.2025955-4-jhubbard@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      104acc32
    • J
      mm/gup: refactor and de-duplicate gup_fast() code · 376a34ef
      由 John Hubbard 提交于 
      There were two nearly identical sets of code for gup_fast() style of
walking the page tables with interrupts disabled.  This has lead to the
usual maintenance problems that arise from having duplicated code.

There is already a core internal routine in gup.c for gup_fast(), so just
enhance it very slightly: allow skipping the fall-back to "slow" (regular)
get_user_pages(), via the new FOLL_FAST_ONLY flag.  Then, just call
internal_get_user_pages_fast() from __get_user_pages_fast(), and adjust
the API to match pre-existing API behavior.

There is a change in behavior from this refactoring: the nested form of
interrupt disabling is used in all gup_fast() variants now.  That's
because there is only one place that interrupt disabling for page walking
is done, and so the safer form is required.  This should, if anything,
eliminate possible (rare) bugs, because the non-nested form of enabling
interrupts was fragile at best.

[jhubbard@nvidia.com: fixup]
  Link: http://lkml.kernel.org/r/20200521233841.1279742-1-jhubbard@nvidia.comSigned-off-by: NJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NChris Wilson <chris@chris-wilson.co.uk>
Cc: Daniel Vetter <daniel@ffwll.ch>
Cc: David Airlie <airlied@linux.ie>
Cc: Jani Nikula <jani.nikula@linux.intel.com>
Cc: "Joonas Lahtinen" <joonas.lahtinen@linux.intel.com>
Cc: Matthew Auld <matthew.auld@intel.com>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
Cc: Souptick Joarder <jrdr.linux@gmail.com>
Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
Link: http://lkml.kernel.org/r/20200519002124.2025955-3-jhubbard@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      376a34ef
  3. 03 6月, 2020 3 次提交
  5. 29 5月, 2020 1 次提交
  7. 20 5月, 2020 1 次提交
  9. 23 4月, 2020 1 次提交
  11. 21 4月, 2020 1 次提交
  13. 11 4月, 2020 4 次提交
  15. 08 4月, 2020 3 次提交
    • P
      userfaultfd: wp: apply _PAGE_UFFD_WP bit · 292924b2
      由 Peter Xu 提交于 
      Firstly, introduce two new flags MM_CP_UFFD_WP[_RESOLVE] for
change_protection() when used with uffd-wp and make sure the two new flags
are exclusively used.  Then,

  - For MM_CP_UFFD_WP: apply the _PAGE_UFFD_WP bit and remove _PAGE_RW
    when a range of memory is write protected by uffd

  - For MM_CP_UFFD_WP_RESOLVE: remove the _PAGE_UFFD_WP bit and recover
    _PAGE_RW when write protection is resolved from userspace

And use this new interface in mwriteprotect_range() to replace the old
MM_CP_DIRTY_ACCT.

Do this change for both PTEs and huge PMDs.  Then we can start to identify
which PTE/PMD is write protected by general (e.g., COW or soft dirty
tracking), and which is for userfaultfd-wp.

Since we should keep the _PAGE_UFFD_WP when doing pte_modify(), add it
into _PAGE_CHG_MASK as well.  Meanwhile, since we have this new bit, we
can be even more strict when detecting uffd-wp page faults in either
do_wp_page() or wp_huge_pmd().

After we're with _PAGE_UFFD_WP, a special case is when a page is both
protected by the general COW logic and also userfault-wp.  Here the
userfault-wp will have higher priority and will be handled first.  Only
after the uffd-wp bit is cleared on the PTE/PMD will we continue to handle
the general COW.  These are the steps on what will happen with such a
page:

  1. CPU accesses write protected shared page (so both protected by
     general COW and uffd-wp), blocked by uffd-wp first because in
     do_wp_page we'll handle uffd-wp first, so it has higher priority
     than general COW.

  2. Uffd service thread receives the request, do UFFDIO_WRITEPROTECT
     to remove the uffd-wp bit upon the PTE/PMD.  However here we
     still keep the write bit cleared.  Notify the blocked CPU.

  3. The blocked CPU resumes the page fault process with a fault
     retry, during retry it'll notice it was not with the uffd-wp bit
     this time but it is still write protected by general COW, then
     it'll go though the COW path in the fault handler, copy the page,
     apply write bit where necessary, and retry again.

  4. The CPU will be able to access this page with write bit set.
Suggested-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Cc: Brian Geffon <bgeffon@google.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-8-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      292924b2
    • P
      mm: merge parameters for change_protection() · 58705444
      由 Peter Xu 提交于 
      change_protection() was used by either the NUMA or mprotect() code,
there's one parameter for each of the callers (dirty_accountable and
prot_numa).  Further, these parameters are passed along the calls:

  - change_protection_range()
  - change_p4d_range()
  - change_pud_range()
  - change_pmd_range()
  - ...

Now we introduce a flag for change_protect() and all these helpers to
replace these parameters.  Then we can avoid passing multiple parameters
multiple times along the way.

More importantly, it'll greatly simplify the work if we want to introduce
any new parameters to change_protection().  In the follow up patches, a
new parameter for userfaultfd write protection will be introduced.

No functional change at all.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NJerome Glisse <jglisse@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Brian Geffon <bgeffon@google.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Cc: Rik van Riel <riel@redhat.com>
Cc: Shaohua Li <shli@fb.com>
Link: http://lkml.kernel.org/r/20200220163112.11409-7-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      58705444
    • A
      mm/vma: make vma_is_accessible() available for general use · 3122e80e
      由 Anshuman Khandual 提交于 
      Lets move vma_is_accessible() helper to include/linux/mm.h which makes it
available for general use.  While here, this replaces all remaining open
encodings for VMA access check with vma_is_accessible().
Signed-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NGeert Uytterhoeven <geert@linux-m68k.org>
Acked-by: NGuo Ren <guoren@kernel.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Guo Ren <guoren@kernel.org>
Cc: Geert Uytterhoeven <geert@linux-m68k.org>
Cc: Ralf Baechle <ralf@linux-mips.org>
Cc: Paul Burton <paulburton@kernel.org>
Cc: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Yoshinori Sato <ysato@users.sourceforge.jp>
Cc: Rich Felker <dalias@libc.org>
Cc: Dave Hansen <dave.hansen@linux.intel.com>
Cc: Andy Lutomirski <luto@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Steven Rostedt <rostedt@goodmis.org>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Alexander Viro <viro@zeniv.linux.org.uk>
Cc: "Aneesh Kumar K.V" <aneesh.kumar@linux.ibm.com>
Cc: Arnaldo Carvalho de Melo <acme@kernel.org>
Cc: Arnd Bergmann <arnd@arndb.de>
Cc: Nick Piggin <npiggin@gmail.com>
Cc: Paul Mackerras <paulus@ozlabs.org>
Cc: Will Deacon <will@kernel.org>
Link: http://lkml.kernel.org/r/1582520593-30704-3-git-send-email-anshuman.khandual@arm.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3122e80e
  17. 03 4月, 2020 9 次提交
    • J
      mmap: remove inline of vm_unmapped_area · baceaf1c
      由 Jaewon Kim 提交于 
      Patch series "mm: mmap: add mmap trace point", v3.

Create mmap trace file and add trace point of vm_unmapped_area().

This patch (of 2):

In preparation for next patch remove inline of vm_unmapped_area and move
code to mmap.c.  There is no logical change.

Also remove unmapped_area[_topdown] out of mm.h, there is no code
calling to them.
Signed-off-by: NJaewon Kim <jaewon31.kim@samsung.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox (Oracle) <willy@infradead.org>
Cc: Michel Lespinasse <walken@google.com>
Cc: Borislav Petkov <bp@suse.de>
Link: http://lkml.kernel.org/r/20200320055823.27089-2-jaewon31.kim@samsung.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      baceaf1c
    • P
      mm: allow VM_FAULT_RETRY for multiple times · 4064b982
      由 Peter Xu 提交于 
      The idea comes from a discussion between Linus and Andrea [1].

Before this patch we only allow a page fault to retry once.  We achieved
this by clearing the FAULT_FLAG_ALLOW_RETRY flag when doing
handle_mm_fault() the second time.  This was majorly used to avoid
unexpected starvation of the system by looping over forever to handle the
page fault on a single page.  However that should hardly happen, and after
all for each code path to return a VM_FAULT_RETRY we'll first wait for a
condition (during which time we should possibly yield the cpu) to happen
before VM_FAULT_RETRY is really returned.

This patch removes the restriction by keeping the FAULT_FLAG_ALLOW_RETRY
flag when we receive VM_FAULT_RETRY.  It means that the page fault handler
now can retry the page fault for multiple times if necessary without the
need to generate another page fault event.  Meanwhile we still keep the
FAULT_FLAG_TRIED flag so page fault handler can still identify whether a
page fault is the first attempt or not.

Then we'll have these combinations of fault flags (only considering
ALLOW_RETRY flag and TRIED flag):

  - ALLOW_RETRY and !TRIED:  this means the page fault allows to
                             retry, and this is the first try

  - ALLOW_RETRY and TRIED:   this means the page fault allows to
                             retry, and this is not the first try

  - !ALLOW_RETRY and !TRIED: this means the page fault does not allow
                             to retry at all

  - !ALLOW_RETRY and TRIED:  this is forbidden and should never be used

In existing code we have multiple places that has taken special care of
the first condition above by checking against (fault_flags &
FAULT_FLAG_ALLOW_RETRY).  This patch introduces a simple helper to detect
the first retry of a page fault by checking against both (fault_flags &
FAULT_FLAG_ALLOW_RETRY) and !(fault_flag & FAULT_FLAG_TRIED) because now
even the 2nd try will have the ALLOW_RETRY set, then use that helper in
all existing special paths.  One example is in __lock_page_or_retry(), now
we'll drop the mmap_sem only in the first attempt of page fault and we'll
keep it in follow up retries, so old locking behavior will be retained.

This will be a nice enhancement for current code [2] at the same time a
supporting material for the future userfaultfd-writeprotect work, since in
that work there will always be an explicit userfault writeprotect retry
for protected pages, and if that cannot resolve the page fault (e.g., when
userfaultfd-writeprotect is used in conjunction with swapped pages) then
we'll possibly need a 3rd retry of the page fault.  It might also benefit
other potential users who will have similar requirement like userfault
write-protection.

GUP code is not touched yet and will be covered in follow up patch.

Please read the thread below for more information.

[1] https://lore.kernel.org/lkml/20171102193644.GB22686@redhat.com/
[2] https://lore.kernel.org/lkml/20181230154648.GB9832@redhat.com/Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Suggested-by: NAndrea Arcangeli <aarcange@redhat.com>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NBrian Geffon <bgeffon@google.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: David Hildenbrand <david@redhat.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160246.9790-1-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4064b982
    • P
      mm: introduce FAULT_FLAG_INTERRUPTIBLE · c270a7ee
      由 Peter Xu 提交于 
      handle_userfaultfd() is currently the only one place in the kernel page
fault procedures that can respond to non-fatal userspace signals.  It was
trying to detect such an allowance by checking against USER & KILLABLE
flags, which was "un-official".

In this patch, we introduced a new flag (FAULT_FLAG_INTERRUPTIBLE) to show
that the fault handler allows the fault procedure to respond even to
non-fatal signals.  Meanwhile, add this new flag to the default fault
flags so that all the page fault handlers can benefit from the new flag.
With that, replacing the userfault check to this one.

Since the line is getting even longer, clean up the fault flags a bit too
to ease TTY users.

Although we've got a new flag and applied it, we shouldn't have any
functional change with this patch so far.
Suggested-by: NLinus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NBrian Geffon <bgeffon@google.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220195348.16302-1-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c270a7ee
    • P
      mm: introduce FAULT_FLAG_DEFAULT · dde16072
      由 Peter Xu 提交于 
      Although there're tons of arch-specific page fault handlers, most of them
are still sharing the same initial value of the page fault flags.  Say,
merely all of the page fault handlers would allow the fault to be retried,
and they also allow the fault to respond to SIGKILL.

Let's define a default value for the fault flags to replace those initial
page fault flags that were copied over.  With this, it'll be far easier to
introduce new fault flag that can be used by all the architectures instead
of touching all the archs.
Signed-off-by: NPeter Xu <peterx@redhat.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Tested-by: NBrian Geffon <bgeffon@google.com>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: Andrea Arcangeli <aarcange@redhat.com>
Cc: Bobby Powers <bobbypowers@gmail.com>
Cc: Denis Plotnikov <dplotnikov@virtuozzo.com>
Cc: "Dr . David Alan Gilbert" <dgilbert@redhat.com>
Cc: Hugh Dickins <hughd@google.com>
Cc: Jerome Glisse <jglisse@redhat.com>
Cc: Johannes Weiner <hannes@cmpxchg.org>
Cc: "Kirill A . Shutemov" <kirill@shutemov.name>
Cc: Martin Cracauer <cracauer@cons.org>
Cc: Marty McFadden <mcfadden8@llnl.gov>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Maya Gokhale <gokhale2@llnl.gov>
Cc: Mel Gorman <mgorman@suse.de>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Mike Rapoport <rppt@linux.vnet.ibm.com>
Cc: Pavel Emelyanov <xemul@openvz.org>
Link: http://lkml.kernel.org/r/20200220160238.9694-1-peterx@redhat.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      dde16072
    • A
      mm/vma: make is_vma_temporary_stack() available for general use · 222100ee
      由 Anshuman Khandual 提交于 
      Currently the declaration and definition for is_vma_temporary_stack() are
scattered.  Lets make is_vma_temporary_stack() helper available for
general use and also drop the declaration from (include/linux/huge_mm.h)
which is no longer required.  While at this, rename this as
vma_is_temporary_stack() in line with existing helpers.  This should not
cause any functional change.
Signed-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1582782965-3274-4-git-send-email-anshuman.khandual@arm.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      222100ee
    • A
      mm/vma: make vma_is_foreign() available for general use · 7969f226
      由 Anshuman Khandual 提交于 
      Idea of a foreign VMA with respect to the present context is very generic.
But currently there are two identical definitions for this in powerpc and
x86 platforms.  Lets consolidate those redundant definitions while making
vma_is_foreign() available for general use later.  This should not cause
any functional change.
Signed-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: Ingo Molnar <mingo@redhat.com>
Link: http://lkml.kernel.org/r/1582782965-3274-3-git-send-email-anshuman.khandual@arm.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      7969f226
    • A
      mm/vma: move VM_NO_KHUGEPAGED into generic header · b4443772
      由 Anshuman Khandual 提交于 
      Patch series "mm/vma: some more minor changes", v2.

The motivation here is to consolidate VMA flags and helpers in generic
memory header and reduce code duplication when ever applicable.  If there
are other possible similar instances which might be missing here, please
do let me me know.  I will be happy to incorporate them.

This patch (of 3):

Move VM_NO_KHUGEPAGED into generic header (include/linux/mm.h).  This just
makes sure that no VMA flag is scattered in individual function files any
longer.  While at this, fix an old comment which is no longer valid.  This
should not cause any functional change.
Signed-off-by: NAnshuman Khandual <anshuman.khandual@arm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Acked-by: NVlastimil Babka <vbabka@suse.cz>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: Michael Ellerman <mpe@ellerman.id.au>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Link: http://lkml.kernel.org/r/1582782965-3274-2-git-send-email-anshuman.khandual@arm.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      b4443772
    • J
      mm/gup: page->hpage_pinned_refcount: exact pin counts for huge pages · 47e29d32
      由 John Hubbard 提交于 
      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: NJan Kara <jack@suse.cz>
Signed-off-by: NJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: Jérôme Glisse <jglisse@redhat.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-8-jhubbard@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      47e29d32
    • J
      mm/gup: track FOLL_PIN pages · 3faa52c0
      由 John Hubbard 提交于 
      Add tracking of pages that were pinned via FOLL_PIN.  This tracking is
implemented via overloading of page->_refcount: pins are added by adding
GUP_PIN_COUNTING_BIAS (1024) to the refcount.  This provides a fuzzy
indication of pinning, and it can have false positives (and that's OK).
Please see the pre-existing Documentation/core-api/pin_user_pages.rst for
details.

As mentioned in pin_user_pages.rst, callers who effectively set FOLL_PIN
(typically via pin_user_pages*()) are required to ultimately free such
pages via unpin_user_page().

Please also note the limitation, discussed in pin_user_pages.rst under the
"TODO: for 1GB and larger huge pages" section.  (That limitation will be
removed in a following patch.)

The effect of a FOLL_PIN flag is similar to that of FOLL_GET, and may be
thought of as "FOLL_GET for DIO and/or RDMA use".

Pages that have been pinned via FOLL_PIN are identifiable via a new
function call:

   bool page_maybe_dma_pinned(struct page *page);

What to do in response to encountering such a page, is left to later
patchsets. There is discussion about this in [1], [2], [3], and [4].

This also changes a BUG_ON(), to a WARN_ON(), in follow_page_mask().

[1] Some slow progress on get_user_pages() (Apr 2, 2019):
    https://lwn.net/Articles/784574/
[2] DMA and get_user_pages() (LPC: Dec 12, 2018):
    https://lwn.net/Articles/774411/
[3] The trouble with get_user_pages() (Apr 30, 2018):
    https://lwn.net/Articles/753027/
[4] LWN kernel index: get_user_pages():
    https://lwn.net/Kernel/Index/#Memory_management-get_user_pages

[jhubbard@nvidia.com: add kerneldoc]
  Link: http://lkml.kernel.org/r/20200307021157.235726-1-jhubbard@nvidia.com
[imbrenda@linux.ibm.com: if pin fails, we need to unpin, a simple put_page will not be enough]
  Link: http://lkml.kernel.org/r/20200306132537.783769-2-imbrenda@linux.ibm.com
[akpm@linux-foundation.org: fix put_compound_head defined but not used]
Suggested-by: NJan Kara <jack@suse.cz>
Suggested-by: NJérôme Glisse <jglisse@redhat.com>
Signed-off-by: NJohn Hubbard <jhubbard@nvidia.com>
Signed-off-by: NClaudio Imbrenda <imbrenda@linux.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Reviewed-by: NJan Kara <jack@suse.cz>
Acked-by: NKirill A. Shutemov <kirill.shutemov@linux.intel.com>
Cc: Ira Weiny <ira.weiny@intel.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: Al Viro <viro@zeniv.linux.org.uk>
Cc: Christoph Hellwig <hch@infradead.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Dave Chinner <david@fromorbit.com>
Cc: Jason Gunthorpe <jgg@ziepe.ca>
Cc: Jonathan Corbet <corbet@lwn.net>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Mike Kravetz <mike.kravetz@oracle.com>
Cc: Shuah Khan <shuah@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Link: http://lkml.kernel.org/r/20200211001536.1027652-7-jhubbard@nvidia.comSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      3faa52c0
  19. 25 3月, 2020 1 次提交
    • T
      mm: Introduce vma_is_special_huge · 2484ca9b
      由 Thomas Hellstrom (VMware) 提交于 
      For VM_PFNMAP and VM_MIXEDMAP vmas that want to support transhuge pages
and -page table entries, introduce vma_is_special_huge() that takes the
same codepaths as vma_is_dax().

The use of "special" follows the definition in memory.c, vm_normal_page():
"Special" mappings do not wish to be associated with a "struct page"
(either it doesn't exist, or it exists but they don't want to touch it)

For PAGE_SIZE pages, "special" is determined per page table entry to be
able to deal with COW pages. But since we don't have huge COW pages,
we can classify a vma as either "special huge" or "normal huge".

Cc: Andrew Morton <akpm@linux-foundation.org>
Cc: Michal Hocko <mhocko@suse.com>
Cc: "Matthew Wilcox (Oracle)" <willy@infradead.org>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Ralph Campbell <rcampbell@nvidia.com>
Cc: "Jérôme Glisse" <jglisse@redhat.com>
Cc: "Christian König" <christian.koenig@amd.com>
Cc: Dan Williams <dan.j.williams@intel.com>
Signed-off-by: NThomas Hellstrom (VMware) <thomas_os@shipmail.org>
Acked-by: NChristian König <christian.koenig@amd.com>
Acked-by: NAndrew Morton <akpm@linux-foundation.org>
      2484ca9b
  21. 17 3月, 2020 1 次提交
    • D
      arm64: Basic Branch Target Identification support · 8ef8f360
      由 Dave Martin 提交于 
      This patch adds the bare minimum required to expose the ARMv8.5
Branch Target Identification feature to userspace.

By itself, this does _not_ automatically enable BTI for any initial
executable pages mapped by execve().  This will come later, but for
now it should be possible to enable BTI manually on those pages by
using mprotect() from within the target process.

Other arches already using the generic mman.h are already using
0x10 for arch-specific prot flags, so we use that for PROT_BTI
here.

For consistency, signal handler entry points in BTI guarded pages
are required to be annotated as such, just like any other function.
This blocks a relatively minor attack vector, but comforming
userspace will have the annotations anyway, so we may as well
enforce them.
Signed-off-by: NMark Brown <broonie@kernel.org>
Signed-off-by: NDave Martin <Dave.Martin@arm.com>
Reviewed-by: NCatalin Marinas <catalin.marinas@arm.com>
Signed-off-by: NCatalin Marinas <catalin.marinas@arm.com>
      8ef8f360
  23. 06 3月, 2020 1 次提交
    • V
      mm, hotplug: fix page online with DEBUG_PAGEALLOC compiled but not enabled · c87cbc1f
      由 Vlastimil Babka 提交于 
      Commit cd02cf1a ("mm/hotplug: fix an imbalance with DEBUG_PAGEALLOC")
fixed memory hotplug with debug_pagealloc enabled, where onlining a page
goes through page freeing, which removes the direct mapping.  Some arches
don't like when the page is not mapped in the first place, so
generic_online_page() maps it first.  This is somewhat wasteful, but
better than special casing page freeing fast paths.

The commit however missed that DEBUG_PAGEALLOC configured doesn't mean
it's actually enabled.  One has to test debug_pagealloc_enabled() since
031bc574 ("mm/debug-pagealloc: make debug-pagealloc boottime
configurable"), or alternatively debug_pagealloc_enabled_static() since
8e57f8ac ("mm, debug_pagealloc: don't rely on static keys too early"),
but this is not done.

As a result, a s390 kernel with DEBUG_PAGEALLOC configured but not enabled
will crash:

Unable to handle kernel pointer dereference in virtual kernel address space
Failing address: 0000000000000000 TEID: 0000000000000483
Fault in home space mode while using kernel ASCE.
AS:0000001ece13400b R2:000003fff7fd000b R3:000003fff7fcc007 S:000003fff7fd7000 P:000000000000013d
Oops: 0004 ilc:2 [#1] SMP
CPU: 1 PID: 26015 Comm: chmem Kdump: loaded Tainted: GX 5.3.18-5-default #1 SLE15-SP2 (unreleased)
Krnl PSW : 0704e00180000000 0000001ecd281b9e (__kernel_map_pages+0x166/0x188)
R:0 T:1 IO:1 EX:1 Key:0 M:1 W:0 P:0 AS:3 CC:2 PM:0 RI:0 EA:3
Krnl GPRS: 0000000000000000 0000000000000800 0000400b00000000 0000000000000100
0000000000000001 0000000000000000 0000000000000002 0000000000000100
0000001ece139230 0000001ecdd98d40 0000400b00000100 0000000000000000
000003ffa17e4000 001fffe0114f7d08 0000001ecd4d93ea 001fffe0114f7b20
Krnl Code: 0000001ecd281b8e: ec17ffff00d8 ahik %r1,%r7,-1
0000001ecd281b94: ec111dbc0355 risbg %r1,%r1,29,188,3
>0000001ecd281b9e: 94fb5006 ni 6(%r5),251
0000001ecd281ba2: 41505008 la %r5,8(%r5)
0000001ecd281ba6: ec51fffc6064 cgrj %r5,%r1,6,1ecd281b9e
0000001ecd281bac: 1a07 ar %r0,%r7
0000001ecd281bae: ec03ff584076 crj %r0,%r3,4,1ecd281a5e
Call Trace:
[<0000001ecd281b9e>] __kernel_map_pages+0x166/0x188
[<0000001ecd4d9516>] online_pages_range+0xf6/0x128
[<0000001ecd2a8186>] walk_system_ram_range+0x7e/0xd8
[<0000001ecda28aae>] online_pages+0x2fe/0x3f0
[<0000001ecd7d02a6>] memory_subsys_online+0x8e/0xc0
[<0000001ecd7add42>] device_online+0x5a/0xc8
[<0000001ecd7d0430>] state_store+0x88/0x118
[<0000001ecd5b9f62>] kernfs_fop_write+0xc2/0x200
[<0000001ecd5064b6>] vfs_write+0x176/0x1e0
[<0000001ecd50676a>] ksys_write+0xa2/0x100
[<0000001ecda315d4>] system_call+0xd8/0x2c8

Fix this by checking debug_pagealloc_enabled_static() before calling
kernel_map_pages(). Backports for kernel before 5.5 should use
debug_pagealloc_enabled() instead. Also add comments.

Fixes: cd02cf1a ("mm/hotplug: fix an imbalance with DEBUG_PAGEALLOC")
Reported-by: NGerald Schaefer <gerald.schaefer@de.ibm.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Reviewed-by: NDavid Hildenbrand <david@redhat.com>
Cc: <stable@vger.kernel.org>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: Qian Cai <cai@lca.pw>
Link: http://lkml.kernel.org/r/20200224094651.18257-1-vbabka@suse.czSigned-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      c87cbc1f
  25. 04 2月, 2020 1 次提交
    • D
      mm/page_alloc.c: initialize memmap of unavailable memory directly · 4b094b78
      由 David Hildenbrand 提交于 
      Let's make sure that all memory holes are actually marked PageReserved(),
that page_to_pfn() produces reliable results, and that these pages are not
detected as "mmap" pages due to the mapcount.

E.g., booting a x86-64 QEMU guest with 4160 MB:

[    0.010585] Early memory node ranges
[    0.010586]   node   0: [mem 0x0000000000001000-0x000000000009efff]
[    0.010588]   node   0: [mem 0x0000000000100000-0x00000000bffdefff]
[    0.010589]   node   0: [mem 0x0000000100000000-0x0000000143ffffff]

max_pfn is 0x144000.

Before this change:

[root@localhost ~]# ./page-types -r -a 0x144000,
             flags      page-count       MB  symbolic-flags                     long-symbolic-flags
0x0000000000000800           16384       64  ___________M_______________________________        mmap
             total           16384       64

After this change:

[root@localhost ~]# ./page-types -r -a 0x144000,
             flags      page-count       MB  symbolic-flags                     long-symbolic-flags
0x0000000100000000           16384       64  ___________________________r_______________        reserved
             total           16384       64

IOW, especially the unavailable physical memory ("memory hole") in the
last section would not get properly marked PageReserved() and is indicated
to be "mmap" memory.

Drop the trace of that function from include/linux/mm.h - nobody else
needs it, and rename it accordingly.

Note: The fake zone/node might not be covered by the zone/node span.  This
is not an urgent issue (for now, we had the same node/zone due to the
zeroing).  We'll need a clean way to mark memory holes (e.g., using a page
type PageHole() if possible or a fake ZONE_INVALID) and eventually stop
marking these memory holes PageReserved().

Link: http://lkml.kernel.org/r/20191211163201.17179-4-david@redhat.comSigned-off-by: NDavid Hildenbrand <david@redhat.com>
Cc: Oscar Salvador <osalvador@suse.de>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Dan Williams <dan.j.williams@intel.com>
Cc: Alexey Dobriyan <adobriyan@gmail.com>
Cc: Bob Picco <bob.picco@oracle.com>
Cc: Daniel Jordan <daniel.m.jordan@oracle.com>
Cc: Michal Hocko <mhocko@suse.com>
Cc: Naoya Horiguchi <n-horiguchi@ah.jp.nec.com>
Cc: Pavel Tatashin <pasha.tatashin@oracle.com>
Cc: Stephen Rothwell <sfr@canb.auug.org.au>
Cc: Steven Sistare <steven.sistare@oracle.com>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      4b094b78
  27. 01 2月, 2020 5 次提交
  29. 21 1月, 2020 1 次提交
  31. 16 1月, 2020 1 次提交
  33. 14 1月, 2020 1 次提交
    • V
      mm, debug_pagealloc: don't rely on static keys too early · 8e57f8ac
      由 Vlastimil Babka 提交于 
      Commit 96a2b03f ("mm, debug_pagelloc: use static keys to enable
debugging") has introduced a static key to reduce overhead when
debug_pagealloc is compiled in but not enabled.  It relied on the
assumption that jump_label_init() is called before parse_early_param()
as in start_kernel(), so when the "debug_pagealloc=on" option is parsed,
it is safe to enable the static key.

However, it turns out multiple architectures call parse_early_param()
earlier from their setup_arch().  x86 also calls jump_label_init() even
earlier, so no issue was found while testing the commit, but same is not
true for e.g.  ppc64 and s390 where the kernel would not boot with
debug_pagealloc=on as found by our QA.

To fix this without tricky changes to init code of multiple
architectures, this patch partially reverts the static key conversion
from 96a2b03f.  Init-time and non-fastpath calls (such as in arch
code) of debug_pagealloc_enabled() will again test a simple bool
variable.  Fastpath mm code is converted to a new
debug_pagealloc_enabled_static() variant that relies on the static key,
which is enabled in a well-defined point in mm_init() where it's
guaranteed that jump_label_init() has been called, regardless of
architecture.

[sfr@canb.auug.org.au: export _debug_pagealloc_enabled_early]
  Link: http://lkml.kernel.org/r/20200106164944.063ac07b@canb.auug.org.au
Link: http://lkml.kernel.org/r/20191219130612.23171-1-vbabka@suse.cz
Fixes: 96a2b03f ("mm, debug_pagelloc: use static keys to enable debugging")
Signed-off-by: NVlastimil Babka <vbabka@suse.cz>
Signed-off-by: NStephen Rothwell <sfr@canb.auug.org.au>
Cc: Joonsoo Kim <iamjoonsoo.kim@lge.com>
Cc: "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com>
Cc: Michal Hocko <mhocko@kernel.org>
Cc: Vlastimil Babka <vbabka@suse.cz>
Cc: Matthew Wilcox <willy@infradead.org>
Cc: Mel Gorman <mgorman@techsingularity.net>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Borislav Petkov <bp@alien8.de>
Cc: Qian Cai <cai@lca.pw>
Cc: <stable@vger.kernel.org>
Signed-off-by: NAndrew Morton <akpm@linux-foundation.org>
Signed-off-by: NLinus Torvalds <torvalds@linux-foundation.org>
      8e57f8ac