[Xen-changelog] [xen-unstable] x86: adjust available memory calculation for Dom0 construction

[Xen patchbot-unstable <patchbot-unstable@xxxxxxxxxxxxxxxxxxx>]

# HG changeset patch
# User Keir Fraser <keir.fraser@xxxxxxxxxx>
# Date 1268329235 0
# Node ID 4152a3ce90a76c96b6c7540271595793ba510df2
# Parent  c9f795ff78b1740d69f2dd392d7886a3e00ba951
x86: adjust available memory calculation for Dom0 construction

With a large number of CPUs, the amount of memory needed to construct
the vCPU structures for Dom0 becomes significant and hence should be
accounted for when calculating the amount of memory to pass to Dom0.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxxxx>

Add code comments and clean up compute_dom0_nr_pages() invocation.

Signed-off-by: Keir Fraser <keir.fraser@xxxxxxxxxx>
---
 xen/arch/x86/domain_build.c |   42 ++++++++++++++++++++----------------------
 1 files changed, 20 insertions(+), 22 deletions(-)

diff -r c9f795ff78b1 -r 4152a3ce90a7 xen/arch/x86/domain_build.c
--- a/xen/arch/x86/domain_build.c       Thu Mar 11 17:15:54 2010 +0000
+++ b/xen/arch/x86/domain_build.c       Thu Mar 11 17:40:35 2010 +0000
@@ -143,16 +143,19 @@ static struct page_info * __init alloc_c
 }
 
 static unsigned long __init compute_dom0_nr_pages(
-#ifdef __x86_64__
-    unsigned long vstart, unsigned long vend, size_t sizeof_long)
-#else
-    void)
-#endif
+    struct domain *d, struct elf_dom_parms *parms, unsigned long initrd_len)
 {
     unsigned long avail = avail_domheap_pages() + initial_images_nrpages();
     unsigned long nr_pages = dom0_nrpages;
     unsigned long min_pages = dom0_min_nrpages;
     unsigned long max_pages = dom0_max_nrpages;
+
+    /* Reserve memory for further dom0 vcpu-struct allocations... */
+    avail -= (opt_dom0_max_vcpus - 1UL)
+             << get_order_from_bytes(sizeof(struct vcpu));
+    /* ...and compat_l4's, if needed. */
+    if ( is_pv_32on64_domain(d) )
+        avail -= opt_dom0_max_vcpus - 1;
 
     /*
      * If domain 0 allocation isn't specified, reserve 1/16th of available
@@ -173,8 +176,8 @@ static unsigned long __init compute_dom0
     nr_pages = min(nr_pages, avail);
 
 #ifdef __x86_64__
-    if ( vstart && dom0_nrpages <= 0 &&
-         (dom0_min_nrpages <= 0 || nr_pages > min_pages) )
+    if ( (parms->p2m_base == UNSET_ADDR) && (dom0_nrpages <= 0) &&
+         ((dom0_min_nrpages <= 0) || (nr_pages > min_pages)) )
     {
         /*
          * Legacy Linux kernels (i.e. such without a XEN_ELFNOTE_INIT_P2M
@@ -184,7 +187,12 @@ static unsigned long __init compute_dom0
          * allocation doesn't consume more than about half the space that's
          * available between params.virt_base and the address space end.
          */
-        unsigned long end = vend + nr_pages * sizeof_long;
+        unsigned long vstart, vend, end;
+        size_t sizeof_long = is_pv_32bit_domain(d) ? sizeof(int) : 
sizeof(long);
+
+        vstart = parms->virt_base;
+        vend = round_pgup(parms->virt_kend) + round_pgup(initrd_len);
+        end = vend + nr_pages * sizeof_long;
 
         if ( end > vstart )
             end += end - vstart;
@@ -367,20 +375,10 @@ int __init construct_dom0(
     {
         d->arch.is_32bit_pv = d->arch.has_32bit_shinfo = 1;
         v->vcpu_info = (void *)&d->shared_info->compat.vcpu_info[0];
-
-        nr_pages = compute_dom0_nr_pages(parms.virt_base,
-            round_pgup(parms.virt_kend) + round_pgup(initrd_len),
-            sizeof(unsigned int));
-    }
-    else if (parms.p2m_base != UNSET_ADDR)
-        nr_pages = compute_dom0_nr_pages(0, 0, 0);
-    else
-        nr_pages = compute_dom0_nr_pages(parms.virt_base,
-            round_pgup(parms.virt_kend) + round_pgup(initrd_len),
-            sizeof(unsigned long));
-#else
-    nr_pages = compute_dom0_nr_pages();
-#endif
+    }
+#endif
+
+    nr_pages = compute_dom0_nr_pages(d, &parms, initrd_len);
 
     if ( parms.pae == PAEKERN_extended_cr3 )
             set_bit(VMASST_TYPE_pae_extended_cr3, &d->vm_assist);

_______________________________________________
Xen-changelog mailing list
Xen-changelog@xxxxxxxxxxxxxxxxxxx
http://lists.xensource.com/xen-changelog