From c673f1a9d994de501b674b2bb6a48bd5e912afe0 Mon Sep 17 00:00:00 2001 From: William Lee Irwin III Date: Sat, 21 Jul 2007 17:11:13 +0200 Subject: [PATCH] i386: divorce CONFIG_X86_PAE from CONFIG_HIGHMEM64G PAE is useful for more than supporting more than 4GB RAM. It supports expanded swapspace and NX executable protections. Some users may want NX or expanded swapspace support without the overhead or instability of highmem. For these reasons, the following patch divorces CONFIG_X86_PAE from CONFIG_HIGHMEM64G. Cc: Mark Lord Signed-off-by: William Irwin Signed-off-by: Andrew Morton Signed-off-by: Andi Kleen Signed-off-by: Linus Torvalds --- arch/i386/Kconfig | 16 +++++++++++----- arch/i386/kernel/setup.c | 8 ++++---- 2 files changed, 15 insertions(+), 9 deletions(-) diff --git a/arch/i386/Kconfig b/arch/i386/Kconfig index 361aca8b3ec3..0790bdf8c1f1 100644 --- a/arch/i386/Kconfig +++ b/arch/i386/Kconfig @@ -548,6 +548,7 @@ config HIGHMEM4G config HIGHMEM64G bool "64GB" depends on !M386 && !M486 + select X86_PAE help Select this if you have a 32-bit processor and more than 4 gigabytes of physical RAM. @@ -577,12 +578,12 @@ choice config VMSPLIT_3G bool "3G/1G user/kernel split" config VMSPLIT_3G_OPT - depends on !HIGHMEM + depends on !X86_PAE bool "3G/1G user/kernel split (for full 1G low memory)" config VMSPLIT_2G bool "2G/2G user/kernel split" config VMSPLIT_2G_OPT - depends on !HIGHMEM + depends on !X86_PAE bool "2G/2G user/kernel split (for full 2G low memory)" config VMSPLIT_1G bool "1G/3G user/kernel split" @@ -602,10 +603,15 @@ config HIGHMEM default y config X86_PAE - bool - depends on HIGHMEM64G - default y + bool "PAE (Physical Address Extension) Support" + default n + depends on !HIGHMEM4G select RESOURCES_64BIT + help + PAE is required for NX support, and furthermore enables + larger swapspace support for non-overcommit purposes. It + has the cost of more pagetable lookup overhead, and also + consumes more pagetable space per process. # Common NUMA Features config NUMA diff --git a/arch/i386/kernel/setup.c b/arch/i386/kernel/setup.c index 2986b48a823f..d474cd639bcb 100644 --- a/arch/i386/kernel/setup.c +++ b/arch/i386/kernel/setup.c @@ -273,18 +273,18 @@ unsigned long __init find_max_low_pfn(void) printk(KERN_WARNING "Warning only %ldMB will be used.\n", MAXMEM>>20); if (max_pfn > MAX_NONPAE_PFN) - printk(KERN_WARNING "Use a PAE enabled kernel.\n"); + printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); else printk(KERN_WARNING "Use a HIGHMEM enabled kernel.\n"); max_pfn = MAXMEM_PFN; #else /* !CONFIG_HIGHMEM */ -#ifndef CONFIG_X86_PAE +#ifndef CONFIG_HIGHMEM64G if (max_pfn > MAX_NONPAE_PFN) { max_pfn = MAX_NONPAE_PFN; printk(KERN_WARNING "Warning only 4GB will be used.\n"); - printk(KERN_WARNING "Use a PAE enabled kernel.\n"); + printk(KERN_WARNING "Use a HIGHMEM64G enabled kernel.\n"); } -#endif /* !CONFIG_X86_PAE */ +#endif /* !CONFIG_HIGHMEM64G */ #endif /* !CONFIG_HIGHMEM */ } else { if (highmem_pages == -1) -- 2.20.1