Re: [RFC PATCH] powerpc/mm/radix: Update pte fragment count from 16 to 256 on radix
From: Aneesh Kumar K.V <hidden>
Date: 2018-02-12 08:52:47
Subsystem:
linux for powerpc (32-bit and 64-bit), the rest · Maintainers:
Madhavan Srinivasan, Linus Torvalds
"Aneesh Kumar K.V" [off-list ref] writes:
quoted hunk ↗ jump to hunk
This needs more performance test. But right now we are wasting lot of space in the level 4 page table. Signed-off-by: Aneesh Kumar K.V <redacted> --- arch/powerpc/include/asm/book3s/64/hash-64k.h | 9 ++++----- arch/powerpc/include/asm/book3s/64/radix-64k.h | 8 ++++++++ 2 files changed, 12 insertions(+), 5 deletions(-)diff --git a/arch/powerpc/include/asm/book3s/64/hash-64k.h b/arch/powerpc/include/asm/book3s/64/hash-64k.h index 3bcf269f8f55..688f9018302e 100644 --- a/arch/powerpc/include/asm/book3s/64/hash-64k.h +++ b/arch/powerpc/include/asm/book3s/64/hash-64k.h@@ -24,16 +24,15 @@ /* PTE flags to conserve for HPTE identification */ #define _PAGE_HPTEFLAGS (H_PAGE_BUSY | H_PAGE_HASHPTE | H_PAGE_COMBO) -/* - * we support 16 fragments per PTE page of 64K size. - */ -#define H_PTE_FRAG_NR 16 /* * We use a 2K PTE page fragment and another 2K for storing * real_pte_t hash index */ #define H_PTE_FRAG_SIZE_SHIFT 12 -#define PTE_FRAG_SIZE (1UL << PTE_FRAG_SIZE_SHIFT) +/* + * we support 16 fragments per PTE page of 64K size. + */ +#define H_PTE_FRAG_NR (PAGE_SIZE >> RADIX_PTE_FRAG_SIZE_SHIFT) #ifndef __ASSEMBLY__ #include <asm/errno.h>diff --git a/arch/powerpc/include/asm/book3s/64/radix-64k.h b/arch/powerpc/include/asm/book3s/64/radix-64k.h index c7e71ba29555..8029732bb6c4 100644 --- a/arch/powerpc/include/asm/book3s/64/radix-64k.h +++ b/arch/powerpc/include/asm/book3s/64/radix-64k.h@@ -10,4 +10,12 @@ #define RADIX_PUD_INDEX_SIZE 9 #define RADIX_PGD_INDEX_SIZE 13 +/* + * We use a 256 byte PTE page fragment in radix + */ +#define RADIX_PTE_FRAG_SIZE_SHIFT 8 +/* + * we support 16 fragments per PTE page of 64K size. + */ +#define RADIX_PTE_FRAG_NR (PAGE_SIZE >> RADIX_PTE_FRAG_SIZE_SHIFT) #endif /* _ASM_POWERPC_PGTABLE_RADIX_64K_H */
missed git refresh
diff --git a/arch/powerpc/mm/pgtable-radix.c b/arch/powerpc/mm/pgtable-radix.c
index 27d096610369..404cdd74bc9c 100644
--- a/arch/powerpc/mm/pgtable-radix.c
+++ b/arch/powerpc/mm/pgtable-radix.c@@ -561,8 +561,8 @@ void __init radix__early_init_mmu(void) /* * For now radix also use the same frag size */ - __pte_frag_nr = H_PTE_FRAG_NR; - __pte_frag_size_shift = H_PTE_FRAG_SIZE_SHIFT; + __pte_frag_nr = RADIX_PTE_FRAG_NR; + __pte_frag_size_shift = RADIX_PTE_FRAG_SIZE_SHIFT; if (!firmware_has_feature(FW_FEATURE_LPAR)) { radix_init_native();