Messages in this thread Patch in this message | | | Date | Thu, 7 Jun 2007 19:35:51 -0700 | From | William Lee Irwin III <> | Subject | divorce CONFIG_X86_PAE from CONFIG_HIGHMEM64G |
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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.
vs. 2.6.22-rc4-mm2
Cc: Mark Lord <lkml@rtr.ca> Cc: Andi Kleen <ak@suse.de> Cc: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: William Irwin <wli@holomorphy.com>
Index: mm-2.6.22-rc4-2/arch/i386/Kconfig =================================================================== --- mm-2.6.22-rc4-2.orig/arch/i386/Kconfig 2007-06-07 00:05:53.609599701 -0700 +++ mm-2.6.22-rc4-2/arch/i386/Kconfig 2007-06-07 17:02:24.333262965 -0700 @@ -544,6 +544,7 @@ config HIGHMEM64G bool "64GB" depends on X86_CMPXCHG64 + select X86_PAE help Select this if you have a 32-bit processor and more than 4 gigabytes of physical RAM. @@ -573,12 +574,12 @@ 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" @@ -598,10 +599,15 @@ 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 Index: mm-2.6.22-rc4-2/arch/i386/kernel/setup.c =================================================================== --- mm-2.6.22-rc4-2.orig/arch/i386/kernel/setup.c 2007-06-06 23:52:18.839168580 -0700 +++ mm-2.6.22-rc4-2/arch/i386/kernel/setup.c 2007-06-07 17:02:24.349263876 -0700 @@ -273,18 +273,18 @@ 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) - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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