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xen: allow balloon driver to use more than one memory region

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Allow the xen balloon driver to populate its list of extra pages from
more than one region of memory.  This will allow platforms to provide
(for example) a region of low memory and a region of high memory.

The maximum possible number of extra regions is 128 (== E820MAX) which
is quite large so xen_extra_mem is placed in __initdata.  This is safe
as both xen_memory_setup() and balloon_init() are in __init.

The balloon regions themselves are not altered (i.e., there is still
only the one region).

Signed-off-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
This commit is contained in:
David Vrabel 2011-09-28 17:46:34 +01:00 committed by Konrad Rzeszutek Wilk
parent b1cbf9b1d6
commit 8b5d44a5ac
3 changed files with 46 additions and 28 deletions
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20
arch/x86/xen/setup.c
View File

@ -37,7 +37,7 @@ extern void xen_syscall_target(void);
extern void xen_syscall32_target(void);
/* Amount of extra memory space we add to the e820 ranges */
phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS] __initdata;
/* Number of pages released from the initial allocation. */
unsigned long xen_released_pages;
@ -59,7 +59,7 @@ static void __init xen_add_extra_mem(unsigned long pages)
unsigned long pfn;
u64 size = (u64)pages * PAGE_SIZE;
u64 extra_start = xen_extra_mem_start + xen_extra_mem_size;
u64 extra_start = xen_extra_mem[0].start + xen_extra_mem[0].size;
if (!pages)
return;
@ -69,7 +69,7 @@ static void __init xen_add_extra_mem(unsigned long pages)
memblock_x86_reserve_range(extra_start, extra_start + size, "XEN EXTRA");
xen_extra_mem_size += size;
xen_extra_mem[0].size += size;
xen_max_p2m_pfn = PFN_DOWN(extra_start + size);
@ -242,7 +242,7 @@ char * __init xen_memory_setup(void)
memcpy(map_raw, map, sizeof(map));
e820.nr_map = 0;
xen_extra_mem_start = mem_end;
xen_extra_mem[0].start = mem_end;
for (i = 0; i < memmap.nr_entries; i++) {
unsigned long long end;
@ -270,8 +270,8 @@ char * __init xen_memory_setup(void)
e820_add_region(end, delta, E820_UNUSABLE);
}
if (map[i].size > 0 && end > xen_extra_mem_start)
xen_extra_mem_start = end;
if (map[i].size > 0 && end > xen_extra_mem[0].start)
xen_extra_mem[0].start = end;
/* Add region if any remains */
if (map[i].size > 0)
@ -279,10 +279,10 @@ char * __init xen_memory_setup(void)
}
/* Align the balloon area so that max_low_pfn does not get set
* to be at the _end_ of the PCI gap at the far end (fee01000).
* Note that xen_extra_mem_start gets set in the loop above to be
* past the last E820 region. */
if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32)))
xen_extra_mem_start = (1ULL<<32);
* Note that the start of balloon area gets set in the loop above
* to be past the last E820 region. */
if (xen_initial_domain() && (xen_extra_mem[0].start < (1ULL<<32)))
xen_extra_mem[0].start = (1ULL<<32);
/*
* In domU, the ISA region is normal, usable memory, but we

44
drivers/xen/balloon.c
View File

@ -555,11 +555,32 @@ void free_xenballooned_pages(int nr_pages, struct page** pages)
}
EXPORT_SYMBOL(free_xenballooned_pages);
static int __init balloon_init(void)
static void __init balloon_add_region(unsigned long start_pfn,
unsigned long pages)
{
unsigned long pfn, extra_pfn_end;
struct page *page;
/*
* If the amount of usable memory has been limited (e.g., with
* the 'mem' command line parameter), don't add pages beyond
* this limit.
*/
extra_pfn_end = min(max_pfn, start_pfn + pages);
for (pfn = start_pfn; pfn < extra_pfn_end; pfn++) {
page = pfn_to_page(pfn);
/* totalram_pages and totalhigh_pages do not
include the boot-time balloon extension, so
don't subtract from it. */
__balloon_append(page);
}
}
static int __init balloon_init(void)
{
int i;
if (!xen_domain())
return -ENODEV;
@ -587,23 +608,12 @@ static int __init balloon_init(void)
/*
* Initialize the balloon with pages from the extra memory
* region (see arch/x86/xen/setup.c).
*
* If the amount of usable memory has been limited (e.g., with
* the 'mem' command line parameter), don't add pages beyond
* this limit.
* regions (see arch/x86/xen/setup.c).
*/
extra_pfn_end = min(max_pfn,
(unsigned long)PFN_DOWN(xen_extra_mem_start
+ xen_extra_mem_size));
for (pfn = PFN_UP(xen_extra_mem_start);
pfn < extra_pfn_end;
pfn++) {
page = pfn_to_page(pfn);
/* totalram_pages and totalhigh_pages do not include the boot-time
balloon extension, so don't subtract from it. */
__balloon_append(page);
}
for (i = 0; i < XEN_EXTRA_MEM_MAX_REGIONS; i++)
if (xen_extra_mem[i].size)
balloon_add_region(PFN_UP(xen_extra_mem[i].start),
PFN_DOWN(xen_extra_mem[i].size));
return 0;
}

10
include/xen/page.h
View File

@ -3,7 +3,15 @@
#include <asm/xen/page.h>
extern phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
struct xen_memory_region {
phys_addr_t start;
phys_addr_t size;
};
#define XEN_EXTRA_MEM_MAX_REGIONS 128 /* == E820MAX */
extern __initdata
struct xen_memory_region xen_extra_mem[XEN_EXTRA_MEM_MAX_REGIONS];
extern unsigned long xen_released_pages;