Messages in this thread Patch in this message | | | Date | Thu, 12 Mar 2009 10:45:08 +0000 | From | "Jan Beulich" <> | Subject | [PATCH] x86-64: improve e820_search_gap() |
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Blindly putting the gap close after max_pfn might be fine for native (though even there I'm uncertain regarding memory hotplug), but will certainly present a problem on Xen. And properly searching for a gap above 4Gb shouldn't hurt native.
Also, make the function static to ensure there are no other users that could depend on the previous behavior regarding the way start_addr gets specified.
Signed-off-by: Jan Beulich <jbeulich@novell.com> Cc: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
--- arch/x86/include/asm/e820.h | 2 -- arch/x86/kernel/e820.c | 11 +++++++++-- 2 files changed, 9 insertions(+), 4 deletions(-)
--- linux-2.6.29-rc7/arch/x86/include/asm/e820.h 2009-03-11 17:52:10.000000000 +0100 +++ 2.6.29-rc7-x86_64-e820-setup-gap-64bit/arch/x86/include/asm/e820.h 2009-03-06 11:25:35.000000000 +0100 @@ -79,8 +79,6 @@ extern u64 e820_remove_range(u64 start, int checktype); extern void update_e820(void); extern void e820_setup_gap(void); -extern int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, - unsigned long start_addr, unsigned long long end_addr); struct setup_data; extern void parse_e820_ext(struct setup_data *data, unsigned long pa_data); --- linux-2.6.29-rc7/arch/x86/kernel/e820.c 2009-03-11 17:52:10.000000000 +0100 +++ 2.6.29-rc7-x86_64-e820-setup-gap-64bit/arch/x86/kernel/e820.c 2009-03-06 11:24:34.000000000 +0100 @@ -533,13 +533,19 @@ static void __init update_e820_saved(voi /* * Search for a gap in the e820 memory space from start_addr to end_addr. */ -__init int e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, +static int __init +e820_search_gap(unsigned long *gapstart, unsigned long *gapsize, unsigned long start_addr, unsigned long long end_addr) { unsigned long long last; int i = e820.nr_map; int found = 0; +#ifdef CONFIG_X86_64 + if (start_addr >= MAX_GAP_END) + last = end_addr ?: (1UL << boot_cpu_data.x86_phys_bits); + else +#endif last = (end_addr && end_addr < MAX_GAP_END) ? end_addr : MAX_GAP_END; while (--i >= 0) { @@ -585,11 +591,12 @@ __init void e820_setup_gap(void) #ifdef CONFIG_X86_64 if (!found) { - gapstart = (max_pfn << PAGE_SHIFT) + 1024*1024; printk(KERN_ERR "PCI: Warning: Cannot find a gap in the 32bit " "address range\n" KERN_ERR "PCI: Unassigned devices with 32bit resource " "registers may break!\n"); + found = e820_search_gap(&gapstart, &gapsize, MAX_GAP_END, 0); + BUG_ON(!found); } #endif
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