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[Xen-devel] [PATCH 1/5] x86: allow specifying the NUMA nodes Dom0 should run on



... by introducing a "dom0_nodes" option augmenting the "dom0_mem" and
"dom0_max_vcpus" ones.

Note that this gives meaning to MEMF_exact_node specified alone (i.e.
implicitly combined with NUMA_NO_NODE): In such a case any node inside
the domain's node mask is acceptable, but no other node. This changed
behavior is (implicitly) being exposed through the memop hypercalls.

Note further that this change doesn't take care of moving the initrd
image into memory matching Dom0's affinity when the initrd doesn't get
copied (because of being part of the initial mapping) anyway.

Signed-off-by: Jan Beulich <jbeulich@xxxxxxxx>
---
I'm uncertain whether range restricting the PXMs permitted for Dom0 is
the right approach (matching what other NUMA code did until recently),
or whether we would instead want to simply limit the number of PXMs we
can handler there (i.e. using a static array instead of a static
bitmap).

--- a/docs/misc/xen-command-line.markdown
+++ b/docs/misc/xen-command-line.markdown
@@ -540,6 +540,15 @@ any dom0 autoballooning feature present 
 _xl.conf(5)_ man page or [Xen Best
 
Practices](http://wiki.xen.org/wiki/Xen_Best_Practices#Xen_dom0_dedicated_memory_and_preventing_dom0_memory_ballooning).
 
+### dom0\_nodes
+
+> `= <integer>[,...]`
+
+Specify the NUMA nodes to place Dom0 on. Defaults for vCPU-s created
+and memory assigned to Dom0 will be adjusted to match the node
+restrictions set up here. Note that the values to be specified here are
+ACPI PXM ones, not Xen internal node numbers.
+
 ### dom0\_shadow
 > `= <boolean>`
 
--- a/xen/arch/x86/domain_build.c
+++ b/xen/arch/x86/domain_build.c
@@ -100,11 +100,58 @@ static void __init parse_dom0_max_vcpus(
 }
 custom_param("dom0_max_vcpus", parse_dom0_max_vcpus);
 
+#define MAX_DOM0_PXM 255
+static __initdata DECLARE_BITMAP(dom0_pxms, MAX_DOM0_PXM + 1);
+
+static void __init parse_dom0_nodes(const char *s)
+{
+    do {
+        unsigned int pxm = simple_strtoul(s, &s, 0);
+
+        if ( pxm <= MAX_DOM0_PXM )
+            __set_bit(pxm, dom0_pxms);
+    } while ( *s++ == ',' );
+}
+custom_param("dom0_nodes", parse_dom0_nodes);
+
+static cpumask_t __initdata dom0_cpus;
+
+static struct vcpu *__init setup_vcpu(struct domain *d, unsigned int vcpu_id,
+                                      unsigned int cpu)
+{
+    struct vcpu *v = alloc_vcpu(d, vcpu_id, cpu);
+
+    if ( v )
+    {
+        if ( !d->is_pinned )
+            cpumask_copy(v->cpu_hard_affinity, &dom0_cpus);
+        cpumask_copy(v->cpu_soft_affinity, &dom0_cpus);
+    }
+
+    return v;
+}
+
+static nodemask_t __initdata dom0_nodes;
+
 unsigned int __init dom0_max_vcpus(void)
 {
-    unsigned max_vcpus;
+    unsigned int pxm, max_vcpus;
+    nodeid_t node;
+
+    for ( pxm = 0; pxm <= MAX_DOM0_PXM; ++pxm )
+        if ( test_bit(pxm, dom0_pxms) &&
+             (node = pxm_to_node(pxm)) != NUMA_NO_NODE )
+            node_set(node, dom0_nodes);
+    nodes_and(dom0_nodes, dom0_nodes, node_online_map);
+    if ( nodes_empty(dom0_nodes) )
+        dom0_nodes = node_online_map;
+    for_each_node_mask ( node, dom0_nodes )
+        cpumask_or(&dom0_cpus, &dom0_cpus, &node_to_cpumask(node));
+    cpumask_and(&dom0_cpus, &dom0_cpus, cpupool0->cpu_valid);
+    if ( cpumask_empty(&dom0_cpus) )
+        cpumask_copy(&dom0_cpus, cpupool0->cpu_valid);
 
-    max_vcpus = num_cpupool_cpus(cpupool0);
+    max_vcpus = cpumask_weight(&dom0_cpus);
     if ( opt_dom0_max_vcpus_min > max_vcpus )
         max_vcpus = opt_dom0_max_vcpus_min;
     if ( opt_dom0_max_vcpus_max < max_vcpus )
@@ -119,12 +166,15 @@ struct vcpu *__init alloc_dom0_vcpu0(str
 {
     unsigned int max_vcpus = dom0_max_vcpus();
 
+    dom0->node_affinity = dom0_nodes;
+    dom0->auto_node_affinity = !!bitmap_empty(dom0_pxms, MAX_DOM0_PXM + 1);
+
     dom0->vcpu = xzalloc_array(struct vcpu *, max_vcpus);
     if ( !dom0->vcpu )
         return NULL;
     dom0->max_vcpus = max_vcpus;
 
-    return alloc_vcpu(dom0, 0, 0);
+    return setup_vcpu(dom0, 0, cpumask_first(&dom0_cpus));
 }
 
 #ifdef CONFIG_SHADOW_PAGING
@@ -156,7 +206,7 @@ static struct page_info * __init alloc_c
     struct domain *d, unsigned long max_pages)
 {
     static unsigned int __initdata last_order = MAX_ORDER;
-    static unsigned int __initdata memflags = MEMF_no_dma;
+    static unsigned int __initdata memflags = MEMF_no_dma|MEMF_exact_node;
     struct page_info *page;
     unsigned int order = get_order_from_pages(max_pages), free_order;
 
@@ -190,7 +240,7 @@ static struct page_info * __init alloc_c
 
         if ( d->tot_pages + (1 << order) > d->max_pages )
             continue;
-        pg2 = alloc_domheap_pages(d, order, 0);
+        pg2 = alloc_domheap_pages(d, order, MEMF_exact_node);
         if ( pg2 > page )
         {
             free_domheap_pages(page, free_order);
@@ -217,10 +267,14 @@ static unsigned long __init dom0_paging_
 static unsigned long __init compute_dom0_nr_pages(
     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, min_pages, max_pages;
+    nodeid_t node;
+    unsigned long avail = 0, nr_pages, min_pages, max_pages;
     bool_t need_paging;
 
+    for_each_node_mask ( node, dom0_nodes )
+        avail += avail_domheap_pages_region(node, 0, 0) +
+                 initial_images_nrpages(node);
+
     /* Reserve memory for further dom0 vcpu-struct allocations... */
     avail -= (d->max_vcpus - 1UL)
              << get_order_from_bytes(sizeof(struct vcpu));
@@ -1230,11 +1284,11 @@ int __init construct_dom0(
 
     printk("Dom0 has maximum %u VCPUs\n", d->max_vcpus);
 
-    cpu = cpumask_first(cpupool0->cpu_valid);
+    cpu = v->processor;
     for ( i = 1; i < d->max_vcpus; i++ )
     {
-        cpu = cpumask_cycle(cpu, cpupool0->cpu_valid);
-        (void)alloc_vcpu(d, i, cpu);
+        cpu = cpumask_cycle(cpu, &dom0_cpus);
+        setup_vcpu(d, i, cpu);
     }
 
     /*
--- a/xen/arch/x86/setup.c
+++ b/xen/arch/x86/setup.c
@@ -140,13 +140,21 @@ static void __init parse_acpi_param(char
 static const module_t *__initdata initial_images;
 static unsigned int __initdata nr_initial_images;
 
-unsigned long __init initial_images_nrpages(void)
+unsigned long __init initial_images_nrpages(nodeid_t node)
 {
+    unsigned long node_start = node_start_pfn(node);
+    unsigned long node_end = node_end_pfn(node);
     unsigned long nr;
     unsigned int i;
 
     for ( nr = i = 0; i < nr_initial_images; ++i )
-        nr += PFN_UP(initial_images[i].mod_end);
+    {
+        unsigned long start = initial_images[i].mod_start;
+        unsigned long end = start + PFN_UP(initial_images[i].mod_end);
+
+        if ( end > node_start && node_end > start )
+            nr += min(node_end, end) - max(node_start, start);
+    }
 
     return nr;
 }
--- a/xen/common/page_alloc.c
+++ b/xen/common/page_alloc.c
@@ -581,7 +581,7 @@ static struct page_info *alloc_heap_page
     struct domain *d)
 {
     unsigned int i, j, zone = 0, nodemask_retry = 0;
-    nodeid_t first_node, node = MEMF_get_node(memflags);
+    nodeid_t first_node, node = MEMF_get_node(memflags), req_node = node;
     unsigned long request = 1UL << order;
     struct page_info *pg;
     nodemask_t nodemask = (d != NULL ) ? d->node_affinity : node_online_map;
@@ -593,7 +593,6 @@ static struct page_info *alloc_heap_page
 
     if ( node == NUMA_NO_NODE )
     {
-        memflags &= ~MEMF_exact_node;
         if ( d != NULL )
         {
             node = next_node(d->last_alloc_node, nodemask);
@@ -654,7 +653,7 @@ static struct page_info *alloc_heap_page
                     goto found;
         } while ( zone-- > zone_lo ); /* careful: unsigned zone may wrap */
 
-        if ( memflags & MEMF_exact_node )
+        if ( (memflags & MEMF_exact_node) && req_node != NUMA_NO_NODE )
             goto not_found;
 
         /* Pick next node. */
@@ -671,7 +670,7 @@ static struct page_info *alloc_heap_page
         if ( node == first_node )
         {
             /* When we have tried all in nodemask, we fall back to others. */
-            if ( nodemask_retry++ )
+            if ( (memflags & MEMF_exact_node) || nodemask_retry++ )
                 goto not_found;
             nodes_andnot(nodemask, node_online_map, nodemask);
             first_node = node = first_node(nodemask);
--- a/xen/include/asm-x86/setup.h
+++ b/xen/include/asm-x86/setup.h
@@ -2,6 +2,7 @@
 #define __X86_SETUP_H_
 
 #include <xen/multiboot.h>
+#include <asm/numa.h>
 
 extern unsigned long xenheap_initial_phys_start;
 
@@ -32,7 +33,7 @@ int construct_dom0(
     void *(*bootstrap_map)(const module_t *),
     char *cmdline);
 
-unsigned long initial_images_nrpages(void);
+unsigned long initial_images_nrpages(nodeid_t node);
 void discard_initial_images(void);
 
 unsigned int dom0_max_vcpus(void);


Attachment: x86-Dom0-nodes.patch
Description: Text document

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