[Xen-devel] [PATCH 1/2] x86: replace nr_irqs sized per-domain arrays with radix trees

["Jan Beulich" <JBeulich@xxxxxxxxxx>]

It would seem possible to fold the two trees into one (making e.g. the
emuirq bits stored in the upper half of the pointer), but I'm not
certain that's worth it as it would make deletion of entries more
cumbersome. Unless pirq-s and emuirq-s were mutually exclusive...

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

--- 2011-04-29.orig/xen/arch/x86/domain.c
+++ 2011-04-29/xen/arch/x86/domain.c
@@ -614,26 +614,16 @@ int arch_domain_create(struct domain *d,
         memset(d->arch.pirq_irq, 0,
                d->nr_pirqs * sizeof(*d->arch.pirq_irq));
 
-        d->arch.irq_pirq = xmalloc_array(int, nr_irqs);
-        if ( !d->arch.irq_pirq )
+        if ( (rc = init_domain_irq_mapping(d)) != 0 )
             goto fail;
-        memset(d->arch.irq_pirq, 0,
-               nr_irqs * sizeof(*d->arch.irq_pirq));
-
-        for ( i = 1; platform_legacy_irq(i); ++i )
-            if ( !IO_APIC_IRQ(i) )
-                d->arch.irq_pirq[i] = d->arch.pirq_irq[i] = i;
 
         if ( is_hvm_domain(d) )
         {
             d->arch.pirq_emuirq = xmalloc_array(int, d->nr_pirqs);
-            d->arch.emuirq_pirq = xmalloc_array(int, nr_irqs);
-            if ( !d->arch.pirq_emuirq || !d->arch.emuirq_pirq )
+            if ( !d->arch.pirq_emuirq )
                 goto fail;
             for (i = 0; i < d->nr_pirqs; i++)
                 d->arch.pirq_emuirq[i] = IRQ_UNBOUND;
-            for (i = 0; i < nr_irqs; i++)
-                d->arch.emuirq_pirq[i] = IRQ_UNBOUND;
         }
 
 
@@ -671,9 +661,8 @@ int arch_domain_create(struct domain *d,
     d->is_dying = DOMDYING_dead;
     vmce_destroy_msr(d);
     xfree(d->arch.pirq_irq);
-    xfree(d->arch.irq_pirq);
     xfree(d->arch.pirq_emuirq);
-    xfree(d->arch.emuirq_pirq);
+    cleanup_domain_irq_mapping(d);
     free_xenheap_page(d->shared_info);
     if ( paging_initialised )
         paging_final_teardown(d);
@@ -726,9 +715,8 @@ void arch_domain_destroy(struct domain *
 
     free_xenheap_page(d->shared_info);
     xfree(d->arch.pirq_irq);
-    xfree(d->arch.irq_pirq);
     xfree(d->arch.pirq_emuirq);
-    xfree(d->arch.emuirq_pirq);
+    cleanup_domain_irq_mapping(d);
 }
 
 unsigned long pv_guest_cr4_fixup(const struct vcpu *v, unsigned long guest_cr4)
--- 2011-04-29.orig/xen/arch/x86/irq.c
+++ 2011-04-29/xen/arch/x86/irq.c
@@ -950,6 +950,58 @@ struct irq_desc *domain_spin_lock_irq_de
     return desc;
 }
 
+static int set_domain_irq_pirq(struct domain *d, int irq, int pirq)
+{
+    int err = radix_tree_insert(&d->arch.irq_pirq, irq, (void *)(long)pirq,
+                                NULL, NULL);
+
+    switch ( err )
+    {
+    case -EEXIST:
+        *radix_tree_lookup_slot(&d->arch.irq_pirq, irq) = (void *)(long)pirq;
+        /* fall through */
+    case 0:
+        d->arch.pirq_irq[pirq] = irq;
+        return 0;
+    }
+
+    return err;
+}
+
+static void clear_domain_irq_pirq(struct domain *d, int irq, int pirq)
+{
+    d->arch.pirq_irq[pirq] = 0;
+    radix_tree_delete(&d->arch.irq_pirq, irq, NULL);
+}
+
+int init_domain_irq_mapping(struct domain *d)
+{
+    unsigned int i;
+    int err;
+
+    INIT_RADIX_TREE(&d->arch.irq_pirq, 0);
+    if ( is_hvm_domain(d) )
+        INIT_RADIX_TREE(&d->arch.hvm_domain.emuirq_pirq, 0);
+
+    for ( i = 1, err = 0; !err && platform_legacy_irq(i); ++i )
+        if ( !IO_APIC_IRQ(i) )
+            err = set_domain_irq_pirq(d, i, i);
+
+    return err;
+}
+
+static void irq_slot_free(void *unused)
+{
+}
+
+void cleanup_domain_irq_mapping(struct domain *d)
+{
+    radix_tree_destroy(&d->arch.irq_pirq, irq_slot_free, NULL);
+    if ( is_hvm_domain(d) )
+        radix_tree_destroy(&d->arch.hvm_domain.emuirq_pirq,
+                           irq_slot_free, NULL);
+}
+
 /* Flush all ready EOIs from the top of this CPU's pending-EOI stack. */
 static void flush_ready_eoi(void)
 {
@@ -1386,7 +1438,7 @@ void pirq_guest_unbind(struct domain *d,
         BUG_ON(irq <= 0);
         desc = irq_to_desc(irq);
         spin_lock_irq(&desc->lock);
-        d->arch.pirq_irq[pirq] = d->arch.irq_pirq[irq] = 0;
+        clear_domain_irq_pirq(d, irq, pirq);
     }
     else
     {
@@ -1544,15 +1596,23 @@ int map_domain_pirq(
             dprintk(XENLOG_G_ERR, "dom%d: irq %d in use\n",
               d->domain_id, irq);
         desc->handler = &pci_msi_type;
-        d->arch.pirq_irq[pirq] = irq;
-        d->arch.irq_pirq[irq] = pirq;
-        setup_msi_irq(pdev, msi_desc, irq);
-        spin_unlock_irqrestore(&desc->lock, flags);
-    } else
+        ret = set_domain_irq_pirq(d, irq, pirq);
+        if ( !ret )
+        {
+            setup_msi_irq(pdev, msi_desc, irq);
+            spin_unlock_irqrestore(&desc->lock, flags);
+        }
+        else
+        {
+            desc->handler = &no_irq_type;
+            spin_unlock_irqrestore(&desc->lock, flags);
+            pci_disable_msi(msi_desc);
+        }
+    }
+    else
     {
         spin_lock_irqsave(&desc->lock, flags);
-        d->arch.pirq_irq[pirq] = irq;
-        d->arch.irq_pirq[irq] = pirq;
+        ret = set_domain_irq_pirq(d, irq, pirq);
         spin_unlock_irqrestore(&desc->lock, flags);
     }
 
@@ -1599,14 +1659,11 @@ int unmap_domain_pirq(struct domain *d, 
     BUG_ON(irq != domain_pirq_to_irq(d, pirq));
 
     if ( !forced_unbind )
-    {
-        d->arch.pirq_irq[pirq] = 0;
-        d->arch.irq_pirq[irq] = 0;
-    }
+        clear_domain_irq_pirq(d, irq, pirq);
     else
     {
         d->arch.pirq_irq[pirq] = -irq;
-        d->arch.irq_pirq[irq] = -pirq;
+        *radix_tree_lookup_slot(&d->arch.irq_pirq, irq) = (void *)(long)-pirq;
     }
 
     spin_unlock_irqrestore(&desc->lock, flags);
@@ -1829,10 +1886,25 @@ int map_domain_emuirq_pirq(struct domain
         return 0;
     }
 
-    d->arch.pirq_emuirq[pirq] = emuirq;
     /* do not store emuirq mappings for pt devices */
     if ( emuirq != IRQ_PT )
-        d->arch.emuirq_pirq[emuirq] = pirq;
+    {
+        int err = radix_tree_insert(&d->arch.hvm_domain.emuirq_pirq, emuirq,
+                                    (void *)((long)pirq + 1), NULL, NULL);
+
+        switch ( err )
+        {
+        case 0:
+            break;
+        case -EEXIST:
+            *radix_tree_lookup_slot(&d->arch.hvm_domain.emuirq_pirq, emuirq) =
+                (void *)((long)pirq + 1);
+            break;
+        default:
+            return err;
+        }
+    }
+    d->arch.pirq_emuirq[pirq] = emuirq;
 
     return 0;
 }
@@ -1860,7 +1932,7 @@ int unmap_domain_pirq_emuirq(struct doma
 
     d->arch.pirq_emuirq[pirq] = IRQ_UNBOUND;
     if ( emuirq != IRQ_PT )
-        d->arch.emuirq_pirq[emuirq] = IRQ_UNBOUND;
+        radix_tree_delete(&d->arch.hvm_domain.emuirq_pirq, emuirq, NULL);
 
  done:
     return ret;
--- 2011-04-29.orig/xen/common/radix-tree.c
+++ 2011-04-29/xen/common/radix-tree.c
@@ -26,7 +26,6 @@
  * o tagging code removed
  * o radix_tree_insert has func parameter for dynamic data struct allocation
  * o radix_tree_destroy added (including recursive helper function)
- * o __init functions must be called explicitly
  * o other include files adapted to Xen
  */
 
@@ -35,6 +34,7 @@
 #include <xen/lib.h>
 #include <xen/types.h>
 #include <xen/errno.h>
+#include <xen/xmalloc.h>
 #include <xen/radix-tree.h>
 #include <asm/cache.h>
 
@@ -49,6 +49,18 @@ static inline unsigned long radix_tree_m
     return height_to_maxindex[height];
 }
 
+static struct radix_tree_node *_node_alloc(void *unused)
+{
+    struct radix_tree_node *node = xmalloc(struct radix_tree_node);
+
+    return node ? memset(node, 0, sizeof(*node)) : node;
+}
+
+static void _node_free(struct radix_tree_node *node)
+{
+    xfree(node);
+}
+
 /*
  * Extend a radix tree so it can store key @index.
  */
@@ -100,6 +112,9 @@ int radix_tree_insert(struct radix_tree_
     int offset;
     int error;
 
+    if (!node_alloc)
+        node_alloc = _node_alloc;
+
     /* Make sure the tree is high enough.  */
     if (index > radix_tree_maxindex(root->height)) {
         error = radix_tree_extend(root, index, node_alloc, arg);
@@ -336,6 +351,9 @@ void *radix_tree_delete(struct radix_tre
     unsigned int height, shift;
     int offset;
 
+    if (!node_free)
+        node_free = _node_free;
+
     height = root->height;
     if (index > radix_tree_maxindex(height))
         goto out;
@@ -420,6 +438,8 @@ void radix_tree_destroy(struct radix_tre
     if (root->height == 0)
         slot_free(root->rnode);
     else {
+        if (!node_free)
+            node_free = _node_free;
         radix_tree_node_destroy(root->rnode, root->height,
                                 slot_free, node_free);
         node_free(root->rnode);
@@ -440,10 +460,14 @@ static unsigned long __init __maxindex(u
     return index;
 }
 
-void __init radix_tree_init(void)
+static int __init radix_tree_init(void)
 {
     unsigned int i;
 
     for (i = 0; i < ARRAY_SIZE(height_to_maxindex); i++)
         height_to_maxindex[i] = __maxindex(i);
+
+    return 0;
 }
+/* pre-SMP just so it runs before 'normal' initcalls */
+presmp_initcall(radix_tree_init);
--- 2011-04-29.orig/xen/common/tmem.c
+++ 2011-04-29/xen/common/tmem.c
@@ -2925,7 +2925,6 @@ static int __init init_tmem(void)
     if ( !tmh_enabled() )
         return 0;
 
-    radix_tree_init();
     if ( tmh_dedup_enabled() )
         for (i = 0; i < 256; i++ )
         {
--- 2011-04-29.orig/xen/include/asm-x86/domain.h
+++ 2011-04-29/xen/include/asm-x86/domain.h
@@ -3,6 +3,7 @@
 
 #include <xen/config.h>
 #include <xen/mm.h>
+#include <xen/radix-tree.h>
 #include <asm/hvm/vcpu.h>
 #include <asm/hvm/domain.h>
 #include <asm/e820.h>
@@ -284,10 +285,9 @@ struct arch_domain
     const char *nested_p2m_function;
 
     /* NB. protected by d->event_lock and by irq_desc[irq].lock */
-    int *irq_pirq;
+    struct radix_tree_root irq_pirq;
     int *pirq_irq;
-    /* pirq to emulated irq and vice versa */
-    int *emuirq_pirq;
+    /* pirq to emulated irq */
     int *pirq_emuirq;
 
     /* Maximum physical-address bitwidth supported by this guest. */
--- 2011-04-29.orig/xen/include/asm-x86/hvm/domain.h
+++ 2011-04-29/xen/include/asm-x86/hvm/domain.h
@@ -59,6 +59,9 @@ struct hvm_domain {
     /* VCPU which is current target for 8259 interrupts. */
     struct vcpu           *i8259_target;
 
+    /* emulated irq to pirq */
+    struct radix_tree_root emuirq_pirq;
+
     /* hvm_print_line() logging. */
 #define HVM_PBUF_SIZE 80
     char                  *pbuf;
--- 2011-04-29.orig/xen/include/asm-x86/irq.h
+++ 2011-04-29/xen/include/asm-x86/irq.h
@@ -143,11 +143,17 @@ int bind_irq_vector(int irq, int vector,
 
 void irq_set_affinity(struct irq_desc *, const cpumask_t *mask);
 
+int init_domain_irq_mapping(struct domain *);
+void cleanup_domain_irq_mapping(struct domain *);
+
 #define domain_pirq_to_irq(d, pirq) ((d)->arch.pirq_irq[pirq])
-#define domain_irq_to_pirq(d, irq) ((d)->arch.irq_pirq[irq])
+#define domain_irq_to_pirq(d, irq) \
+    ((long)radix_tree_lookup(&(d)->arch.irq_pirq, irq))
 #define PIRQ_ALLOCATED -1
 #define domain_pirq_to_emuirq(d, pirq) ((d)->arch.pirq_emuirq[pirq])
-#define domain_emuirq_to_pirq(d, emuirq) ((d)->arch.emuirq_pirq[emuirq])
+#define domain_emuirq_to_pirq(d, emuirq) \
+    (((long)radix_tree_lookup(&(d)->arch.hvm_domain.emuirq_pirq, emuirq) ?: \
+     IRQ_UNBOUND + 1) - 1)
 #define IRQ_UNBOUND -1
 #define IRQ_PT -2
 
--- 2011-04-29.orig/xen/include/xen/radix-tree.h
+++ 2011-04-29/xen/include/xen/radix-tree.h
@@ -73,6 +73,5 @@ void *radix_tree_delete(struct radix_tre
 unsigned int
 radix_tree_gang_lookup(struct radix_tree_root *root, void **results,
                        unsigned long first_index, unsigned int max_items);
-void radix_tree_init(void);
 
 #endif /* _XEN_RADIX_TREE_H */

Attachment: x86-irq_pirq-radix-tree.patch
Description: Text document

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