[PATCH 03/24] xen: dynamically allocate p2m tables

Jeremy Fitzhardinge
2009-03-13T08:13:44Z

From: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>

Saves about 128k static object size.

Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
---
arch/x86/xen/mmu.c | 38 +++++++++++++++++++++++++++++---------
1 files changed, 29 insertions(+), 9 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index d534986..05280b4 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -159,18 +159,14 @@ DEFINE_PER_CPU(unsigned long, xen_current_cr3); /* actual vcpu cr3 */
#define TOP_ENTRIES (MAX_DOMAIN_PAGES / P2M_ENTRIES_PER_PAGE)

/* Placeholder for holes in the address space */
-static unsigned long p2m_missing[P2M_ENTRIES_PER_PAGE] __page_aligned_data =
- { [ 0 ... P2M_ENTRIES_PER_PAGE-1 ] = ~0UL };
+static unsigned long *p2m_missing;

/* Array of pointers to pages containing p2m entries */
-static unsigned long *p2m_top[TOP_ENTRIES] __page_aligned_data =
- { [ 0 ... TOP_ENTRIES - 1] = &p2m_missing[0] };
+static unsigned long **p2m_top;

/* Arrays of p2m arrays expressed in mfns used for save/restore */
-static unsigned long p2m_top_mfn[TOP_ENTRIES] __page_aligned_bss;
-
-static unsigned long p2m_top_mfn_list[TOP_ENTRIES / P2M_ENTRIES_PER_PAGE]
- __page_aligned_bss;
+static unsigned long *p2m_top_mfn;
+static unsigned long *p2m_top_mfn_list;

static inline unsigned p2m_top_index(unsigned long pfn)
{
@@ -183,18 +179,28 @@ static inline unsigned p2m_index(unsigned long pfn)
return pfn % P2M_ENTRIES_PER_PAGE;
}

+#define SIZE_TOP_MFN sizeof(*p2m_top_mfn) * TOP_ENTRIES
+#define SIZE_TOP_MFN_LIST sizeof(*p2m_top_mfn_list) * \
+ (TOP_ENTRIES / P2M_ENTRIES_PER_PAGE)
+
+RESERVE_BRK(xen_top_mfn, SIZE_TOP_MFN);
+RESERVE_BRK(xen_top_mfn_list, SIZE_TOP_MFN_LIST);
+
/* Build the parallel p2m_top_mfn structures */
void xen_setup_mfn_list_list(void)
{
unsigned pfn, idx;

+ p2m_top_mfn = extend_brk(SIZE_TOP_MFN, PAGE_SIZE);
+ p2m_top_mfn_list = extend_brk(SIZE_TOP_MFN_LIST, PAGE_SIZE);
+
for (pfn = 0; pfn < MAX_DOMAIN_PAGES; pfn += P2M_ENTRIES_PER_PAGE) {
unsigned topidx = p2m_top_index(pfn);

p2m_top_mfn[topidx] = virt_to_mfn(p2m_top[topidx]);
}

- for (idx = 0; idx < ARRAY_SIZE(p2m_top_mfn_list); idx++) {
+ for (idx = 0; idx < (TOP_ENTRIES / P2M_ENTRIES_PER_PAGE); idx++) {
unsigned topidx = idx * P2M_ENTRIES_PER_PAGE;
p2m_top_mfn_list[idx] = virt_to_mfn(&p2m_top_mfn[topidx]);
}
@@ -206,12 +212,26 @@ void xen_setup_mfn_list_list(void)
HYPERVISOR_shared_info->arch.max_pfn = xen_start_info->nr_pages;
}

+#define SIZE_P2M_MISSING sizeof(*p2m_missing) * P2M_ENTRIES_PER_PAGE
+#define SIZE_P2M_TOP sizeof(*p2m_top) * TOP_ENTRIES
+RESERVE_BRK(xen_p2m_missing, SIZE_P2M_MISSING);
+RESERVE_BRK(xen_p2m_top, SIZE_P2M_TOP);
+
/* Set up p2m_top to point to the domain-builder provided p2m pages */
void __init xen_build_dynamic_phys_to_machine(void)
{
unsigned long *mfn_list = (unsigned long *)xen_start_info->mfn_list;
unsigned long max_pfn = min(MAX_DOMAIN_PAGES, xen_start_info->nr_pages);
unsigned pfn;
+ unsigned i;
+
+ p2m_missing = extend_brk(SIZE_P2M_MISSING, PAGE_SIZE);
+ for(i = 0; i < P2M_ENTRIES_PER_PAGE; i++)
+ p2m_missing[i] = ~0ul;
+
+ p2m_top = extend_brk(SIZE_P2M_TOP, PAGE_SIZE);
+ for(i = 0; i < TOP_ENTRIES; i++)
+ p2m_top[i] = p2m_missing;

for (pfn = 0; pfn < max_pfn; pfn += P2M_ENTRIES_PER_PAGE) {
unsigned topidx = p2m_top_index(pfn);
--
1.6.0.6