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| author | Rashmica Gupta <rashmicy@gmail.com> | 2016-02-19 08:38:47 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2016-04-11 13:30:44 +0300 |
| commit | a7ee539584acf4a565b7439ceaea8401ec210353 (patch) | |
| tree | 08c7625cf57fbc37535c3a68d85d678abd579d72 /arch/powerpc/Kconfig | |
| parent | 6a0bcab9c6c337e14689cabd276f00649e980cf1 (diff) | |
| download | linux-a7ee539584acf4a565b7439ceaea8401ec210353.tar.xz | |
powerpc/Kconfig: Update config option based on page size.
Currently on PPC64 changing kernel pagesize from 4K to 64K leaves
FORCE_MAX_ZONEORDER set to 13 - which produces a compile error.
The error occurs because of the following constraint (from
include/linux/mmzone.h) being violated:
MAX_ORDER -1 + PAGESHIFT <= SECTION_SIZE_BITS.
Expanding this out, we get:
FORCE_MAX_ZONEBITS <= 25 - PAGESHIFT,
which requires, for a 64K page, FORCE_MAX_ZONEBITS <= 9. Thus set max
value of FORCE_MAX_ZONEORDER for 64K pages to 9, and 4K pages to 13.
Also, check the minimum value:
In include/linux/huge_mm.h, we have the constraint HPAGE_PMD_ORDER <
MAX_ORDER which expands out to:
PTE_INDEX_SIZE < FORCE_MAX_ZONEORDER.
PTE_INDEX_SIZE is:
9 (4k hash or no hash 4K pgtable) or
8 (64K hash or no hash 64K pgtable).
Thus a min value of 8 for 64K pages and 9 for 4K pages is reasonable.
So, update the range of FORCE_MAX_ZONEORDER from 9-64 to 8-9 for 64K pages
and from 13-64 to 9-13 for 4K pages.
Signed-off-by: Rashmica Gupta <rashmicy@gmail.com>
Reviewed-by: Balbir Singh <bsingharora@gmail.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/Kconfig')
| -rw-r--r-- | arch/powerpc/Kconfig | 4 |
1 files changed, 2 insertions, 2 deletions
diff --git a/arch/powerpc/Kconfig b/arch/powerpc/Kconfig index 7cd32c038286..fbebde0771c8 100644 --- a/arch/powerpc/Kconfig +++ b/arch/powerpc/Kconfig @@ -605,9 +605,9 @@ endchoice config FORCE_MAX_ZONEORDER int "Maximum zone order" - range 9 64 if PPC64 && PPC_64K_PAGES + range 8 9 if PPC64 && PPC_64K_PAGES default "9" if PPC64 && PPC_64K_PAGES - range 13 64 if PPC64 && !PPC_64K_PAGES + range 9 13 if PPC64 && !PPC_64K_PAGES default "13" if PPC64 && !PPC_64K_PAGES range 9 64 if PPC32 && PPC_16K_PAGES default "9" if PPC32 && PPC_16K_PAGES |