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| author | Michael Ellerman <mpe@ellerman.id.au> | 2019-03-14 15:54:53 +0300 |
|---|---|---|
| committer | Michael Ellerman <mpe@ellerman.id.au> | 2019-04-20 15:02:11 +0300 |
| commit | eea86aa4171d4960f0fcdc99dab358c224d53ffe (patch) | |
| tree | 38e0d193c517da93546adf865cb3a16f9593488e /arch/powerpc/include/asm/book3s/64/radix-64k.h | |
| parent | 6c84f8c5cbfb4bf728f88296bc035c4a401c3423 (diff) | |
| download | linux-eea86aa4171d4960f0fcdc99dab358c224d53ffe.tar.xz | |
powerpc/mm/64: Document the sizes of/sizes mapped by Pxx_INDEX_SIZE
Add comments describing the size in bytes of the various levels of the
page table tree, and the size of the virtual address space mapped by
each level, to make it clear what the sizes are without having to also
look up other definitions.
The code that calculates the sizes actually uses sizeof(pgd_t) etc.,
so in theory these comments could skew vs the code, but the size of
pgd_t etc. is unlikely to change very often.
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Reviewed-by: Aneesh Kumar K.V <aneesh.kumar@linux.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
Diffstat (limited to 'arch/powerpc/include/asm/book3s/64/radix-64k.h')
| -rw-r--r-- | arch/powerpc/include/asm/book3s/64/radix-64k.h | 8 |
1 files changed, 4 insertions, 4 deletions
diff --git a/arch/powerpc/include/asm/book3s/64/radix-64k.h b/arch/powerpc/include/asm/book3s/64/radix-64k.h index ccb78ca9d0c5..54e33828b0fb 100644 --- a/arch/powerpc/include/asm/book3s/64/radix-64k.h +++ b/arch/powerpc/include/asm/book3s/64/radix-64k.h @@ -5,10 +5,10 @@ /* * For 64K page size supported index is 13/9/9/5 */ -#define RADIX_PTE_INDEX_SIZE 5 /* 2MB huge page */ -#define RADIX_PMD_INDEX_SIZE 9 /* 1G huge page */ -#define RADIX_PUD_INDEX_SIZE 9 -#define RADIX_PGD_INDEX_SIZE 13 +#define RADIX_PTE_INDEX_SIZE 5 // size: 8B << 5 = 256B, maps 2^5 x 64K = 2MB +#define RADIX_PMD_INDEX_SIZE 9 // size: 8B << 9 = 4KB, maps 2^9 x 2MB = 1GB +#define RADIX_PUD_INDEX_SIZE 9 // size: 8B << 9 = 4KB, maps 2^9 x 1GB = 512GB +#define RADIX_PGD_INDEX_SIZE 13 // size: 8B << 13 = 64KB, maps 2^13 x 512GB = 4PB /* * We use a 256 byte PTE page fragment in radix |