From 41151e77a4d96ea138cede6d84c955aa4769ce74 Mon Sep 17 00:00:00 2001 From: Becky Bruce Date: Tue, 28 Jun 2011 09:54:48 +0000 Subject: powerpc: Hugetlb for BookE Enable hugepages on Freescale BookE processors. This allows the kernel to use huge TLB entries to map pages, which can greatly reduce the number of TLB misses and the amount of TLB thrashing experienced by applications with large memory footprints. Care should be taken when using this on FSL processors, as the number of large TLB entries supported by the core is low (16-64) on current processors. The supported set of hugepage sizes include 4m, 16m, 64m, 256m, and 1g. Page sizes larger than the max zone size are called "gigantic" pages and must be allocated on the command line (and cannot be deallocated). This is currently only fully implemented for Freescale 32-bit BookE processors, but there is some infrastructure in the code for 64-bit BooKE. Signed-off-by: Becky Bruce Signed-off-by: David Gibson Signed-off-by: Benjamin Herrenschmidt --- arch/powerpc/include/asm/page.h | 31 ++++++++++++++++++++++++++++++- 1 file changed, 30 insertions(+), 1 deletion(-) (limited to 'arch/powerpc/include/asm/page.h') diff --git a/arch/powerpc/include/asm/page.h b/arch/powerpc/include/asm/page.h index 2cd664ef0a5..dd9c4fd038e 100644 --- a/arch/powerpc/include/asm/page.h +++ b/arch/powerpc/include/asm/page.h @@ -36,6 +36,18 @@ #define PAGE_SIZE (ASM_CONST(1) << PAGE_SHIFT) +#ifndef __ASSEMBLY__ +#ifdef CONFIG_HUGETLB_PAGE +extern unsigned int HPAGE_SHIFT; +#else +#define HPAGE_SHIFT PAGE_SHIFT +#endif +#define HPAGE_SIZE ((1UL) << HPAGE_SHIFT) +#define HPAGE_MASK (~(HPAGE_SIZE - 1)) +#define HUGETLB_PAGE_ORDER (HPAGE_SHIFT - PAGE_SHIFT) +#define HUGE_MAX_HSTATE (MMU_PAGE_COUNT-1) +#endif + /* We do define AT_SYSINFO_EHDR but don't use the gate mechanism */ #define __HAVE_ARCH_GATE_AREA 1 @@ -158,6 +170,24 @@ extern phys_addr_t kernstart_addr; #define is_kernel_addr(x) ((x) >= PAGE_OFFSET) #endif +/* + * Use the top bit of the higher-level page table entries to indicate whether + * the entries we point to contain hugepages. This works because we know that + * the page tables live in kernel space. If we ever decide to support having + * page tables at arbitrary addresses, this breaks and will have to change. + */ +#ifdef CONFIG_PPC64 +#define PD_HUGE 0x8000000000000000 +#else +#define PD_HUGE 0x80000000 +#endif + +/* + * Some number of bits at the level of the page table that points to + * a hugepte are used to encode the size. This masks those bits. + */ +#define HUGEPD_SHIFT_MASK 0x3f + #ifndef __ASSEMBLY__ #undef STRICT_MM_TYPECHECKS @@ -243,7 +273,6 @@ typedef unsigned long pgprot_t; #endif typedef struct { signed long pd; } hugepd_t; -#define HUGEPD_SHIFT_MASK 0x3f #ifdef CONFIG_HUGETLB_PAGE static inline int hugepd_ok(hugepd_t hpd) -- cgit v1.2.3