From: Alex Williamson <alex.williamson@hp.com>
Date: Thu, 9 Aug 2007 02:48:11 +0000 (-0600)
Subject: [IA64] Saner dom0 memory and cpu defaults
X-Git-Tag: archive/raspbian/4.8.0-1+rpi1~1^2~15014
X-Git-Url: https://dgit.raspbian.org/%22http:/www.example.com/cgi/%22https:/%22bookmarks:///%22http:/www.example.com/cgi/%22https:/%22bookmarks:/?a=commitdiff_plain;h=5fb08ad077677262b781d51919d04aee7c212e05;p=xen.git

[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>
---

diff --git a/xen/arch/ia64/xen/domain.c b/xen/arch/ia64/xen/domain.c
index 406b434b74..5d5691c95d 100644
--- a/xen/arch/ia64/xen/domain.c
+++ b/xen/arch/ia64/xen/domain.c
@@ -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(struct domain *d, struct elf_binary *elf,
 	}
 }
 
-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"
@@ -1262,6 +1296,8 @@ int __init construct_dom0(struct domain *d,
 
 	printk("*** LOADING DOMAIN 0 ***\n");
 
+	calc_dom0_size();
+
 	max_pages = dom0_size / PAGE_SIZE;
 	d->max_pages = max_pages;
 	d->tot_pages = 0;
diff --git a/xen/arch/ia64/xen/xensetup.c b/xen/arch/ia64/xen/xensetup.c
index bcdb30d3e5..8d2143eb0c 100644
--- a/xen/arch/ia64/xen/xensetup.c
+++ b/xen/arch/ia64/xen/xensetup.c
@@ -46,7 +46,6 @@ int find_max_pfn (unsigned long, unsigned long, void *);
 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,