qemu-devel
[Top][All Lists]
Advanced

[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]

[Qemu-devel] [PATCH 25/40] memory: add ref/unref


From: Paolo Bonzini
Subject: [Qemu-devel] [PATCH 25/40] memory: add ref/unref
Date: Tue, 7 May 2013 16:17:03 +0200

Signed-off-by: Paolo Bonzini <address@hidden>
---
 include/exec/memory.h |   34 ++++++++++++++++++++++++++++++++++
 memory.c              |   14 ++++++++++++++
 2 files changed, 48 insertions(+), 0 deletions(-)

diff --git a/include/exec/memory.h b/include/exec/memory.h
index 5c20bac..ebac085 100644
--- a/include/exec/memory.h
+++ b/include/exec/memory.h
@@ -253,6 +253,40 @@ struct MemoryListener {
 void memory_region_init(MemoryRegion *mr,
                         const char *name,
                         uint64_t size);
+
+/**
+ * memory_region_ref: Add 1 to a memory region's reference count
+ *
+ * Whenever memory regions are accessed outside the BQL, they need to be
+ * preserved against hot-unplug.  MemoryRegions actually do not have their
+ * own reference count; they piggyback on a QOM object, their "owner".
+ * This function adds a reference to the owner.
+ *
+ * All MemoryRegions must have an owner if they can disappear, even if the
+ * device they belong to operates exclusively under the BQL.  This is because
+ * the region could be returned at any time by memory_region_find, and this
+ * is usually under guest control.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region; any subregions beyond this size will be clipped
+ */
+void memory_region_ref(MemoryRegion *mr);
+
+/**
+ * memory_region_ref: Remove 1 to a memory region's reference count
+ *
+ * Whenever memory regions are accessed outside the BQL, they need to be
+ * preserved against hot-unplug.  MemoryRegions actually do not have their
+ * own reference count; they piggyback on a QOM object, their "owner".
+ * This function removes a reference to the owner and possibly destroys it.
+ *
+ * @mr: the #MemoryRegion to be initialized
+ * @name: used for debugging; not visible to the user or ABI
+ * @size: size of the region; any subregions beyond this size will be clipped
+ */
+void memory_region_unref(MemoryRegion *mr);
+
 /**
  * memory_region_init_io: Initialize an I/O memory region.
  *
diff --git a/memory.c b/memory.c
index f7fddb1..c7ab19c 100644
--- a/memory.c
+++ b/memory.c
@@ -1061,6 +1061,20 @@ void memory_region_set_owner(MemoryRegion *mr,
     }
 }
 
+void memory_region_ref(MemoryRegion *mr)
+{
+    if (mr && mr->owner) {
+        object_ref(mr->owner);
+    }
+}
+
+void memory_region_unref(MemoryRegion *mr)
+{
+    if (mr && mr->owner) {
+        object_unref(mr->owner);
+    }
+}
+
 uint64_t memory_region_size(MemoryRegion *mr)
 {
     if (int128_eq(mr->size, int128_2_64())) {
-- 
1.7.1





reply via email to

[Prev in Thread] Current Thread [Next in Thread]