Mailing List Archive

From: David Vrabel <david.vrabel@citrix.com>

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>
---
arch/x86/xen/setup.c | 20 ++++++++++----------
drivers/xen/balloon.c | 44 +++++++++++++++++++++++++++-----------------
include/xen/page.h | 10 +++++++++-
3 files changed, 46 insertions(+), 28 deletions(-)

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index c983717..0c8e974 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -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
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 9efb993..fc43b53 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -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;
}
diff --git a/include/xen/page.h b/include/xen/page.h
index 92b61f8..12765b6 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -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;

--
1.7.2.5


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