[Xen-devel] [RFC PATCH V2 04/14] Dynamically allocate d->evtchn

[Wei Liu <wei.liu2@xxxxxxxxxx>]

As we move to N level evtchn we need bigger d->evtchn, as a result
this will bloat struct domain. So move this array out of struct domain
and allocate a dedicated page for it.

Signed-off-by: Wei Liu <wei.liu2@xxxxxxxxxx>
---
 xen/common/event_channel.c |   17 +++++++++++++++--
 xen/include/xen/sched.h    |    2 +-
 2 files changed, 16 insertions(+), 3 deletions(-)

diff --git a/xen/common/event_channel.c b/xen/common/event_channel.c
index bc5db10..a5d96ab 100644
--- a/xen/common/event_channel.c
+++ b/xen/common/event_channel.c
@@ -1172,16 +1172,27 @@ void notify_via_xen_event_channel(struct domain *ld, 
int lport)
 
 int evtchn_init(struct domain *d)
 {
+    BUILD_BUG_ON(sizeof(struct evtchn *) * NR_EVTCHN_BUCKETS > PAGE_SIZE);
+    d->evtchn = alloc_xenheap_page();
+
+    if ( d->evtchn == NULL )
+        return -ENOMEM;
+    clear_page(d->evtchn);
+
     spin_lock_init(&d->event_lock);
     d->evtchn_level = EVTCHN_DEFAULT_LEVEL; /* = 2 */
-    if ( get_free_port(d) != 0 )
+    if ( get_free_port(d) != 0 ) {
+        free_xenheap_page(d->evtchn);
         return -EINVAL;
+    }
     evtchn_from_port(d, 0)->state = ECS_RESERVED;
 
 #if MAX_VIRT_CPUS > BITS_PER_LONG
     d->poll_mask = xmalloc_array(unsigned long, BITS_TO_LONGS(MAX_VIRT_CPUS));
-    if ( !d->poll_mask )
+    if ( !d->poll_mask ) {
+        free_xenheap_page(d->evtchn);
         return -ENOMEM;
+    }
     bitmap_zero(d->poll_mask, MAX_VIRT_CPUS);
 #endif
 
@@ -1215,6 +1226,8 @@ void evtchn_destroy(struct domain *d)
     spin_unlock(&d->event_lock);
 
     clear_global_virq_handlers(d);
+
+    free_xenheap_page(d->evtchn);
 }
 
 
diff --git a/xen/include/xen/sched.h b/xen/include/xen/sched.h
index aa97407..c876892 100644
--- a/xen/include/xen/sched.h
+++ b/xen/include/xen/sched.h
@@ -276,7 +276,7 @@ struct domain
     spinlock_t       rangesets_lock;
 
     /* Event channel information. */
-    struct evtchn   *evtchn[NR_EVTCHN_BUCKETS];
+    struct evtchn  **evtchn;
     spinlock_t       event_lock;
     unsigned int     evtchn_level;
 
-- 
1.7.10.4


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