Mailing List Archive

# HG changeset patch
# User Alex Williamson <alex.williamson@hp.com>
# Date 1186627691 21600
# Node ID 87a72ba32301ceb894e065d760953aa98730c0cd
# Parent cc83df4c96d60aad1508975b70b902f7deb9e635
[IA64] Saner dom0 memory and cpu defaults

Some ia64 xen dom0 tweaks:
* Increase default memory allocation from 512M to 4G
* Increase default vcpu allocation from 1 to 4
* Implement rough calculation of what the maximum memory
that can be safely allocated to dom0 is
* If need be, scale down requested memory allocation to fit
available memory, rather than simply panicking
* If dom0_mem=0 is specified, allocate all available mem

Signed-off-by: Jarod Wilson <jwilson@redhat.com>
---
xen/arch/ia64/xen/domain.c | 44 +++++++++++++++++++++++++++++++++++++++----
xen/arch/ia64/xen/xensetup.c | 3 --
2 files changed, 40 insertions(+), 7 deletions(-)

diff -r cc83df4c96d6 -r 87a72ba32301 xen/arch/ia64/xen/domain.c
--- a/xen/arch/ia64/xen/domain.c Mon Aug 06 21:40:47 2007 -0600
+++ b/xen/arch/ia64/xen/domain.c Wed Aug 08 20:48:11 2007 -0600
@@ -52,10 +52,11 @@
#include <asm/perfmon.h>
#include <public/vcpu.h>

-static unsigned long __initdata dom0_size = 512*1024*1024;
+/* dom0_size: default memory allocation for dom0 (~4GB) */
+static unsigned long __initdata dom0_size = 4096UL*1024UL*1024UL;

/* dom0_max_vcpus: maximum number of VCPUs to create for dom0. */
-static unsigned int __initdata dom0_max_vcpus = 1;
+static unsigned int __initdata dom0_max_vcpus = 4;
integer_param("dom0_max_vcpus", dom0_max_vcpus);

extern char dom0_command_line[];
@@ -1195,8 +1196,41 @@ static void __init loaddomainelfimage(st
}
}

-void __init alloc_dom0(void)
-{
+static void __init calc_dom0_size(void)
+{
+ unsigned long domheap_pages;
+ unsigned long p2m_pages;
+ unsigned long spare_hv_pages;
+ unsigned long max_dom0_size;
+
+ /* Estimate maximum memory we can safely allocate for dom0
+ * by subtracting the p2m table allocation and a chunk of memory
+ * for DMA and PCI mapping from the available domheap pages. The
+ * chunk for DMA, PCI, etc., is a guestimate, as xen doesn't seem
+ * to have a good idea of what those requirements might be ahead
+ * of time, calculated at 1MB per 4GB of system memory */
+ domheap_pages = avail_domheap_pages();
+ p2m_pages = domheap_pages / PTRS_PER_PTE;
+ spare_hv_pages = domheap_pages / 4096;
+ max_dom0_size = (domheap_pages - (p2m_pages + spare_hv_pages))
+ * PAGE_SIZE;
+ printk("Maximum permitted dom0 size: %luMB\n",
+ max_dom0_size / (1024*1024));
+
+ /* validate proposed dom0_size, fix up as needed */
+ if (dom0_size > max_dom0_size) {
+ printk("Reducing dom0 memory allocation from %luK to %luK "
+ "to fit available memory\n",
+ dom0_size / 1024, max_dom0_size / 1024);
+ dom0_size = max_dom0_size;
+ }
+
+ /* dom0_mem=0 can be passed in to give all available mem to dom0 */
+ if (dom0_size == 0) {
+ printk("Allocating all available memory to dom0\n");
+ dom0_size = max_dom0_size;
+ }
+
/* Check dom0 size. */
if (dom0_size < 4 * 1024 * 1024) {
panic("dom0_mem is too small, boot aborted"
@@ -1261,6 +1295,8 @@ int __init construct_dom0(struct domain
BUG_ON(v->is_initialised);

printk("*** LOADING DOMAIN 0 ***\n");
+
+ calc_dom0_size();

max_pages = dom0_size / PAGE_SIZE;
d->max_pages = max_pages;
diff -r cc83df4c96d6 -r 87a72ba32301 xen/arch/ia64/xen/xensetup.c
--- a/xen/arch/ia64/xen/xensetup.c Mon Aug 06 21:40:47 2007 -0600
+++ b/xen/arch/ia64/xen/xensetup.c Wed Aug 08 20:48:11 2007 -0600
@@ -46,7 +46,6 @@ extern void early_setup_arch(char **);
extern void early_setup_arch(char **);
extern void late_setup_arch(char **);
extern void hpsim_serial_init(void);
-extern void alloc_dom0(void);
extern void setup_per_cpu_areas(void);
extern void mem_init(void);
extern void init_IRQ(void);
@@ -469,8 +468,6 @@ void __init start_kernel(void)

trap_init();

- alloc_dom0();
-
init_xenheap_pages(__pa(xen_heap_start), xenheap_phys_end);
printk("Xen heap: %luMB (%lukB)\n",
(xenheap_phys_end-__pa(xen_heap_start)) >> 20,

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