[Xen-changelog] If a Linux guest is allocated more memory than it can use (due to

[BitKeeper Bot <riel@xxxxxxxxxxx>]

ChangeSet 1.1792, 2005/03/16 09:46:54+00:00, kaf24@xxxxxxxxxxxxxxxxxxxx

        If a Linux guest is allocated more memory than it can use (due to
        highmem constraints) it will now give that RAM back to Xen.
        Signed-off-by: Keir Fraser <keir@xxxxxxxxxxxxx>



 linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c      |   28 ++++++++++++++-----
 linux-2.6.11-xen-sparse/arch/xen/i386/kernel/setup.c |   25 ++++++++++++----
 2 files changed, 40 insertions(+), 13 deletions(-)


diff -Nru a/linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c 
b/linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c
--- a/linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c   2005-03-16 05:06:30 
-05:00
+++ b/linux-2.4.29-xen-sparse/arch/xen/kernel/setup.c   2005-03-16 05:06:30 
-05:00
@@ -377,15 +377,31 @@
 
     paging_init();
 
-    /* Make sure we have a large enough P->M table. */
-    if ( max_pfn > xen_start_info.nr_pages )
+    /* Make sure we have a correctly sized P->M table. */
+    if ( max_pfn != xen_start_info.nr_pages )
     {
         phys_to_machine_mapping = alloc_bootmem_low_pages(
             max_pfn * sizeof(unsigned long));
-        memset(phys_to_machine_mapping, ~0, max_pfn * sizeof(unsigned long));
-        memcpy(phys_to_machine_mapping,
-               (unsigned long *)xen_start_info.mfn_list,
-               xen_start_info.nr_pages * sizeof(unsigned long));
+        if ( max_pfn > xen_start_info.nr_pages )
+        {
+            memset(phys_to_machine_mapping, ~0,
+                   max_pfn * sizeof(unsigned long));
+            memcpy(phys_to_machine_mapping,
+                   (unsigned long *)xen_start_info.mfn_list,
+                   xen_start_info.nr_pages * sizeof(unsigned long));
+        }
+        else
+        {
+            memcpy(phys_to_machine_mapping,
+                   (unsigned long *)xen_start_info.mfn_list,
+                   max_pfn * sizeof(unsigned long));
+            if (HYPERVISOR_dom_mem_op(
+                MEMOP_decrease_reservation,
+                (unsigned long *)xen_start_info.mfn_list + max_pfn,
+                xen_start_info.nr_pages - max_pfn, 0) !=
+                (xen_start_info.nr_pages - max_pfn))
+                BUG();
+        }
         free_bootmem(__pa(xen_start_info.mfn_list), 
                      PFN_PHYS(PFN_UP(xen_start_info.nr_pages *
                                      sizeof(unsigned long))));
diff -Nru a/linux-2.6.11-xen-sparse/arch/xen/i386/kernel/setup.c 
b/linux-2.6.11-xen-sparse/arch/xen/i386/kernel/setup.c
--- a/linux-2.6.11-xen-sparse/arch/xen/i386/kernel/setup.c      2005-03-16 
05:06:31 -05:00
+++ b/linux-2.6.11-xen-sparse/arch/xen/i386/kernel/setup.c      2005-03-16 
05:06:31 -05:00
@@ -1491,15 +1491,26 @@
 #endif
        paging_init();
 
-       /* Make sure we have a large enough P->M table. */
-       if (max_pfn > xen_start_info.nr_pages) {
+       /* Make sure we have a correctly sized P->M table. */
+       if (max_pfn != xen_start_info.nr_pages) {
                phys_to_machine_mapping = alloc_bootmem_low_pages(
                        max_pfn * sizeof(unsigned long));
-               memset(phys_to_machine_mapping, ~0,
-                       max_pfn * sizeof(unsigned long));
-               memcpy(phys_to_machine_mapping,
-                       (unsigned long *)xen_start_info.mfn_list,
-                       xen_start_info.nr_pages * sizeof(unsigned long));
+               if (max_pfn > xen_start_info.nr_pages) {
+                       memset(phys_to_machine_mapping, ~0,
+                               max_pfn * sizeof(unsigned long));
+                       memcpy(phys_to_machine_mapping,
+                               (unsigned long *)xen_start_info.mfn_list,
+                               xen_start_info.nr_pages * sizeof(unsigned 
long));
+               } else {
+                       memcpy(phys_to_machine_mapping,
+                               (unsigned long *)xen_start_info.mfn_list,
+                               max_pfn * sizeof(unsigned long));
+                       if (HYPERVISOR_dom_mem_op(
+                               MEMOP_decrease_reservation,
+                               (unsigned long *)xen_start_info.mfn_list + 
max_pfn,
+                               xen_start_info.nr_pages - max_pfn, 0) !=
+                           (xen_start_info.nr_pages - max_pfn)) BUG();
+               }
                free_bootmem(
                        __pa(xen_start_info.mfn_list), 
                        PFN_PHYS(PFN_UP(xen_start_info.nr_pages *


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