This allows sharing flat views between address spaces (AS) when
the same root memory region is used when creating a new address space.
This is done by walking through all ASes and caching one FlatView per
a physical root MR (i.e. not aliased).
This removes search for duplicates from address_space_init_shareable() as
FlatViews are shared elsewhere and keeping as::ref_count correct seems
an unnecessary and useless complication.
This should cause no change and memory use or boot time yet.
Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru>
---
Changes:
v4:
* used g_hash_table_new_full() instead of g_hash_table_new() +
g_hash_table_foreach_remove()
* cached last hash table of FV globally
v3:
* got rid of global and per-AS lists of FlatView objects
---
memory.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++-----------
1 file changed, 46 insertions(+), 11 deletions(-)
diff --git a/memory.c b/memory.c
index 9868d0f57c..1083fe9130 100644
--- a/memory.c
+++ b/memory.c
@@ -47,6 +47,8 @@ static QTAILQ_HEAD(memory_listeners, MemoryListener)
memory_listeners
static QTAILQ_HEAD(, AddressSpace) address_spaces
= QTAILQ_HEAD_INITIALIZER(address_spaces);
+static GHashTable *flat_views;
+
typedef struct AddrRange AddrRange;
/*
@@ -925,11 +927,49 @@ static void
address_space_update_topology_pass(AddressSpace *as,
}
}
-static void address_space_update_topology(AddressSpace *as)
+static void flatviews_init(void)
+{
+ if (flat_views) {
+ return;
+ }
+
+ flat_views = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,
+ (GDestroyNotify) flatview_unref);
+}
+
+static void flatviews_reset(void)
+{
+ AddressSpace *as;
+
+ if (flat_views) {
+ g_hash_table_unref(flat_views);
+ flat_views = NULL;
+ }
+ flatviews_init();
+
+ /* Render unique FVs */
+ QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
+ MemoryRegion *physmr = memory_region_get_flatview_root(as->root);
+ FlatView *new_view = g_hash_table_lookup(flat_views, physmr);
+
+ if (new_view) {
+ continue;
+ }
+
+ new_view = generate_memory_topology(physmr);
+ g_hash_table_insert(flat_views, physmr, new_view);
+ }
+}
+
+static void flatview_set_to_address_space(AddressSpace *as)
{
FlatView *old_view = address_space_get_flatview(as);
- MemoryRegion *physmr = memory_region_get_flatview_root(old_view->root);
- FlatView *new_view = generate_memory_topology(physmr);
+ MemoryRegion *physmr = memory_region_get_flatview_root(as->root);
+ FlatView *new_view = g_hash_table_lookup(flat_views, physmr);
+
+ assert(new_view);
+
+ flatview_ref(new_view);
if (!QTAILQ_EMPTY(&as->listeners)) {
address_space_update_topology_pass(as, old_view, new_view, false);
@@ -965,10 +1005,12 @@ void memory_region_transaction_commit(void)
--memory_region_transaction_depth;
if (!memory_region_transaction_depth) {
if (memory_region_update_pending) {
+ flatviews_reset();
+
MEMORY_LISTENER_CALL_GLOBAL(begin, Forward);
QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
- address_space_update_topology(as);
+ flatview_set_to_address_space(as);
address_space_update_ioeventfds(as);
}
memory_region_update_pending = false;
@@ -2691,13 +2733,6 @@ AddressSpace *address_space_init_shareable(MemoryRegion
*root, const char *name)
{
AddressSpace *as;
- QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {
- if (root == as->root && as->malloced) {
- as->ref_count++;
- return as;
- }
- }
-
as = g_malloc0(sizeof *as);
address_space_init(as, root, name);
as->malloced = true;
--
2.11.0
