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The 8xx has 4 page sizes: 4k, 16k, 512k and 8M
4k and 16k can be selected at build time as standard page sizes,
and 512k and 8M are hugepages.
When 4k standard pages are selected, 16k pages are not available.
Allow 16k pages as hugepages when 4k pages are used.
To allow that, implement arch_make_huge_pte() which receives
the necessary arguments to allow setting the PTE in accordance
with the page size:
- 512 k pages must have _PAGE_HUGE and _PAGE_SPS. They are set
by pte_mkhuge(). arch_make_huge_pte() does nothing.
- 16 k pages must have only _PAGE_SPS. arch_make_huge_pte() clears
_PAGE_HUGE.
Signed-off-by: Christophe Leroy <[email protected]>
Signed-off-by: Michael Ellerman <[email protected]>
Link: https://lore.kernel.org/r/a518abc29266a708dfbccc8fce9ae6694fe4c2c6.1598862623.git.christophe.leroy@csgroup.eu
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When remapping an anonymous, private mapping, if MREMAP_DONTUNMAP is set,
the source mapping will not be removed. The remap operation will be
performed as it would have been normally by moving over the page tables to
the new mapping. The old vma will have any locked flags cleared, have no
pagetables, and any userfaultfds that were watching that range will
continue watching it.
For a mapping that is shared or not anonymous, MREMAP_DONTUNMAP will cause
the mremap() call to fail. Because MREMAP_DONTUNMAP always results in
moving a VMA you MUST use the MREMAP_MAYMOVE flag, it's not possible to
resize a VMA while also moving with MREMAP_DONTUNMAP so old_len must
always be equal to the new_len otherwise it will return -EINVAL.
We hope to use this in Chrome OS where with userfaultfd we could write an
anonymous mapping to disk without having to STOP the process or worry
about VMA permission changes.
This feature also has a use case in Android, Lokesh Gidra has said that
"As part of using userfaultfd for GC, We'll have to move the physical
pages of the java heap to a separate location. For this purpose mremap
will be used. Without the MREMAP_DONTUNMAP flag, when I mremap the java
heap, its virtual mapping will be removed as well. Therefore, we'll
require performing mmap immediately after. This is not only time
consuming but also opens a time window where a native thread may call mmap
and reserve the java heap's address range for its own usage. This flag
solves the problem."
[[email protected]: v6]
Link: http://lkml.kernel.org/r/[email protected]
[[email protected]: v7]
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Brian Geffon <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Tested-by: Lokesh Gidra <[email protected]>
Reviewed-by: Minchan Kim <[email protected]>
Acked-by: Kirill A. Shutemov <[email protected]>
Acked-by: Vlastimil Babka <[email protected]>
Cc: "Michael S . Tsirkin" <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Andy Lutomirski <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Sonny Rao <[email protected]>
Cc: Minchan Kim <[email protected]>
Cc: Joel Fernandes <[email protected]>
Cc: Yu Zhao <[email protected]>
Cc: Jesse Barnes <[email protected]>
Cc: Nathan Chancellor <[email protected]>
Cc: Florian Weimer <[email protected]>
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Linus Torvalds <[email protected]>
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Now that we have 3 mmap flags shared by all architectures,
let's move them into the common header.
This will help discourage future architectures from duplicating code.
Signed-off-by: Michael S. Tsirkin <[email protected]>
Signed-off-by: Arnd Bergmann <[email protected]>
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ARM64 architecture also supports 32MB and 512MB HugeTLB page sizes. This
just adds mmap() system call argument encoding for them.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Anshuman Khandual <[email protected]>
Acked-by: Punit Agrawal <[email protected]>
Acked-by: Mike Kravetz <[email protected]>
Cc: Michal Hocko <[email protected]>
Cc: Will Deacon <[email protected]>
Cc: Catalin Marinas <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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license
Many user space API headers are missing licensing information, which
makes it hard for compliance tools to determine the correct license.
By default are files without license information under the default
license of the kernel, which is GPLV2. Marking them GPLV2 would exclude
them from being included in non GPLV2 code, which is obviously not
intended. The user space API headers fall under the syscall exception
which is in the kernels COPYING file:
NOTE! This copyright does *not* cover user programs that use kernel
services by normal system calls - this is merely considered normal use
of the kernel, and does *not* fall under the heading of "derived work".
otherwise syscall usage would not be possible.
Update the files which contain no license information with an SPDX
license identifier. The chosen identifier is 'GPL-2.0 WITH
Linux-syscall-note' which is the officially assigned identifier for the
Linux syscall exception. SPDX license identifiers are a legally binding
shorthand, which can be used instead of the full boiler plate text.
This patch is based on work done by Thomas Gleixner and Kate Stewart and
Philippe Ombredanne. See the previous patch in this series for the
methodology of how this patch was researched.
Reviewed-by: Kate Stewart <[email protected]>
Reviewed-by: Philippe Ombredanne <[email protected]>
Reviewed-by: Thomas Gleixner <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>
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A non-default huge page size can be encoded in the flags argument of the
mmap system call. The definitions for these encodings are in arch
specific header files. However, all architectures use the same values.
Consolidate all the definitions in the primary user header file
(uapi/linux/mman.h). Include definitions for all known huge page sizes.
Use the generic encoding definitions in hugetlb_encode.h as the basis
for these definitions.
Link: http://lkml.kernel.org/r/[email protected]
Signed-off-by: Mike Kravetz <[email protected]>
Acked-by: Michal Hocko <[email protected]>
Cc: Andi Kleen <[email protected]>
Cc: Andrea Arcangeli <[email protected]>
Cc: Aneesh Kumar K.V <[email protected]>
Cc: Anshuman Khandual <[email protected]>
Cc: Arnd Bergmann <[email protected]>
Cc: Davidlohr Bueso <[email protected]>
Cc: Matthew Wilcox <[email protected]>
Cc: Michael Kerrisk <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
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Signed-off-by: David Howells <[email protected]>
Acked-by: Arnd Bergmann <[email protected]>
Acked-by: Thomas Gleixner <[email protected]>
Acked-by: Michael Kerrisk <[email protected]>
Acked-by: Paul E. McKenney <[email protected]>
Acked-by: Dave Jones <[email protected]>
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