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| author |   Kirill A. Shutemov <kirill.shutemov@linux.intel.com> | 2023-03-15 14:31:33 +0300 |
|---|---|---|
| committer |   Andrew Morton <akpm@linux-foundation.org> | 2023-04-05 19:42:46 -0700 |
| commit | 23baf831a32c04f9a968812511540b1b3e648bf5 (patch) | |
| tree | fcaca52cefbef2707710ce057f58fb1c955a0559 /arch/sh/mm/Kconfig | |
| parent | iommu: fix MAX_ORDER usage in __iommu_dma_alloc_pages() (diff) | |
| download | wireguard-linux-23baf831a32c04f9a968812511540b1b3e648bf5.tar.xz wireguard-linux-23baf831a32c04f9a968812511540b1b3e648bf5.zip | |
mm, treewide: redefine MAX_ORDER sanely
MAX_ORDER currently defined as number of orders page allocator supports:
user can ask buddy allocator for page order between 0 and MAX_ORDER-1.
This definition is counter-intuitive and lead to number of bugs all over
the kernel.
Change the definition of MAX_ORDER to be inclusive: the range of orders
user can ask from buddy allocator is 0..MAX_ORDER now.
[kirill@shutemov.name: fix min() warning]
Link: https://lkml.kernel.org/r/20230315153800.32wib3n5rickolvh@box
[akpm@linux-foundation.org: fix another min_t warning]
[kirill@shutemov.name: fixups per Zi Yan]
Link: https://lkml.kernel.org/r/20230316232144.b7ic4cif4kjiabws@box.shutemov.name
[akpm@linux-foundation.org: fix underlining in docs]
Link: https://lore.kernel.org/oe-kbuild-all/202303191025.VRCTk6mP-lkp@intel.com/
Link: https://lkml.kernel.org/r/20230315113133.11326-11-kirill.shutemov@linux.intel.com
Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
Reviewed-by: Michael Ellerman <mpe@ellerman.id.au> [powerpc]
Cc: "Kirill A. Shutemov" <kirill@shutemov.name>
Cc: Zi Yan <ziy@nvidia.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Diffstat (limited to 'arch/sh/mm/Kconfig')
| -rw-r--r-- | arch/sh/mm/Kconfig | 17 |
1 files changed, 7 insertions, 10 deletions
diff --git a/arch/sh/mm/Kconfig b/arch/sh/mm/Kconfig index 411fdc0901f7..40271090bd7d 100644 --- a/arch/sh/mm/Kconfig +++ b/arch/sh/mm/Kconfig @@ -20,13 +20,13 @@ config PAGE_OFFSET config ARCH_FORCE_MAX_ORDER int "Maximum zone order" - range 9 64 if PAGE_SIZE_16KB - default "9" if PAGE_SIZE_16KB - range 7 64 if PAGE_SIZE_64KB - default "7" if PAGE_SIZE_64KB - range 11 64 - default "14" if !MMU - default "11" + range 8 63 if PAGE_SIZE_16KB + default "8" if PAGE_SIZE_16KB + range 6 63 if PAGE_SIZE_64KB + default "6" if PAGE_SIZE_64KB + range 10 63 + default "13" if !MMU + default "10" help The kernel memory allocator divides physically contiguous memory blocks into "zones", where each zone is a power of two number of @@ -35,9 +35,6 @@ config ARCH_FORCE_MAX_ORDER blocks of physically contiguous memory, then you may need to increase this value. - This config option is actually maximum order plus one. For example, - a value of 11 means that the largest free memory block is 2^10 pages. - The page size is not necessarily 4KB. Keep this in mind when choosing a value for this option. |