04 Feb, 2020
4 commits
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struct mm_struct is quite large (~1664 bytes) and so allocating on the
stack may cause problems as the kernel stack size is small.Since ptdump_walk_pgd_level_core() was only allocating the structure so
that it could modify the pgd argument we can instead introduce a pgd
override in struct mm_walk and pass this down the call stack to where it
is needed.Since the correct mm_struct is now being passed down, it is now also
unnecessary to take the mmap_sem semaphore because ptdump_walk_pgd() will
now take the semaphore on the real mm.[steven.price@arm.com: restore missed arm64 changes]
Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com
Link: http://lkml.kernel.org/r/20200108145710.34314-1-steven.price@arm.com
Signed-off-by: Steven Price
Reported-by: Stephen Rothwell
Cc: Catalin Marinas
Cc: Albert Ou
Cc: Alexandre Ghiti
Cc: Andy Lutomirski
Cc: Ard Biesheuvel
Cc: Arnd Bergmann
Cc: Benjamin Herrenschmidt
Cc: Borislav Petkov
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 -
The pte_hole() callback is called at multiple levels of the page tables.
Code dumping the kernel page tables needs to know what at what depth the
missing entry is. Add this is an extra parameter to pte_hole(). When the
depth isn't know (e.g. processing a vma) then -1 is passed.The depth that is reported is the actual level where the entry is missing
(ignoring any folding that is in place), i.e. any levels where
PTRS_PER_P?D is set to 1 are ignored.Note that depth starts at 0 for a PGD so that PUD/PMD/PTE retain their
natural numbers as levels 2/3/4.Link: http://lkml.kernel.org/r/20191218162402.45610-16-steven.price@arm.com
Signed-off-by: Steven Price
Tested-by: Zong Li
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
Signed-off-by: Andrew Morton
Signed-off-by: Linus Torvalds -
Since 48684a65b4e3: "mm: pagewalk: fix misbehavior of walk_page_range for
vma(VM_PFNMAP)", page_table_walk() will report any kernel area as a hole,
because it lacks a vma.This means each arch has re-implemented page table walking when needed,
for example in the per-arch ptdump walker.Remove the requirement to have a vma in the generic code and add a new
function walk_page_range_novma() which ignores the VMAs and simply walks
the page tables.Link: http://lkml.kernel.org/r/20191218162402.45610-13-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 -
pgd_entry() and pud_entry() were removed by commit 0b1fbfe50006c410
("mm/pagewalk: remove pgd_entry() and pud_entry()") because there were no
users. We're about to add users so reintroduce them, along with
p4d_entry() as we now have 5 levels of tables.Note that commit a00cc7d9dd93d66a ("mm, x86: add support for PUD-sized
transparent hugepages") already re-added pud_entry() but with different
semantics to the other callbacks. This commit reverts the semantics back
to match the other callbacks.To support hmm.c which now uses the new semantics of pud_entry() a new
member ('action') of struct mm_walk is added which allows the callbacks to
either descend (ACTION_SUBTREE, the default), skip (ACTION_CONTINUE) or
repeat the callback (ACTION_AGAIN). hmm.c is then updated to call
pud_trans_huge_lock() itself and make use of the splitting/retry logic of
the core code.After this change pud_entry() is called for all entries, not just
transparent huge pages.[arnd@arndb.de: fix unused variable warning]
Link: http://lkml.kernel.org/r/20200107204607.1533842-1-arnd@arndb.de
Link: http://lkml.kernel.org/r/20191218162402.45610-12-steven.price@arm.com
Signed-off-by: Steven Price
Signed-off-by: Arnd Bergmann
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
06 Nov, 2019
1 commit
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For users that want to travers all page table entries pointing into a
region of a struct address_space mapping, introduce a walk_page_mapping()
function.The walk_page_mapping() function will be initially be used for dirty-
tracking in virtual graphics drivers.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
Reviewed-by: Andrew Morton
07 Sep, 2019
2 commits
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The mm_walk structure currently mixed data and code. Split out the
operations vectors into a new mm_walk_ops structure, and while we are
changing the API also declare the mm_walk structure inside the
walk_page_range and walk_page_vma functions.Based on patch from Linus Torvalds.
Link: https://lore.kernel.org/r/20190828141955.22210-3-hch@lst.de
Signed-off-by: Christoph Hellwig
Reviewed-by: Thomas Hellstrom
Reviewed-by: Steven Price
Reviewed-by: Jason Gunthorpe
Signed-off-by: Jason Gunthorpe -
Add a new header for the two handful of users of the walk_page_range /
walk_page_vma interface instead of polluting all users of mm.h with it.Link: https://lore.kernel.org/r/20190828141955.22210-2-hch@lst.de
Signed-off-by: Christoph Hellwig
Reviewed-by: Thomas Hellstrom
Reviewed-by: Steven Price
Reviewed-by: Jason Gunthorpe
Signed-off-by: Jason Gunthorpe
