[Date Prev][Date Next][Thread Prev][Thread Next][Date Index][Thread Index]
[Qemu-devel] [PATCH qemu v4 13/18] memory: Do not allocate FlatView in a
From: |
Alexey Kardashevskiy |
Subject: |
[Qemu-devel] [PATCH qemu v4 13/18] memory: Do not allocate FlatView in address_space_init |
Date: |
Wed, 20 Sep 2017 21:46:32 +1000 |
This creates a new AS object without any FlatView as
memory_region_transaction_commit() may want to reuse the empty FV.
Signed-off-by: Alexey Kardashevskiy <address@hidden>
---
I do not really want to add view!=NULL into
flatview_ref()/flatview_unref() as this is quite special case when
view==NULL.
---
memory.c | 29 +++++++++++++++++++++++------
1 file changed, 23 insertions(+), 6 deletions(-)
diff --git a/memory.c b/memory.c
index 1083fe9130..aa8a49539d 100644
--- a/memory.c
+++ b/memory.c
@@ -963,22 +963,37 @@ static void flatviews_reset(void)
static void flatview_set_to_address_space(AddressSpace *as)
{
- FlatView *old_view = address_space_get_flatview(as);
+ FlatView *old_view = address_space_to_flatview(as);
MemoryRegion *physmr = memory_region_get_flatview_root(as->root);
FlatView *new_view = g_hash_table_lookup(flat_views, physmr);
assert(new_view);
+ if (old_view == new_view) {
+ return;
+ }
+
+ if (old_view) {
+ flatview_ref(old_view);
+ }
+
flatview_ref(new_view);
if (!QTAILQ_EMPTY(&as->listeners)) {
- address_space_update_topology_pass(as, old_view, new_view, false);
- address_space_update_topology_pass(as, old_view, new_view, true);
+ FlatView tmpview = { 0 }, *old_view2 = old_view;
+
+ if (!old_view2) {
+ old_view2 = &tmpview;
+ }
+ address_space_update_topology_pass(as, old_view2, new_view, false);
+ address_space_update_topology_pass(as, old_view2, new_view, true);
}
/* Writes are protected by the BQL. */
atomic_rcu_set(&as->current_map, new_view);
- flatview_unref(old_view);
+ if (old_view) {
+ flatview_unref(old_view);
+ }
/* Note that all the old MemoryRegions are still alive up to this
* point. This relieves most MemoryListeners from the need to
@@ -986,7 +1001,9 @@ static void flatview_set_to_address_space(AddressSpace *as)
* outside the iothread mutex, in which case precise reference
* counting is necessary.
*/
- flatview_unref(old_view);
+ if (old_view) {
+ flatview_unref(old_view);
+ }
}
void memory_region_transaction_begin(void)
@@ -2704,7 +2721,7 @@ void address_space_init(AddressSpace *as, MemoryRegion
*root, const char *name)
as->ref_count = 1;
as->root = root;
as->malloced = false;
- as->current_map = flatview_new(root);
+ as->current_map = NULL;
as->ioeventfd_nb = 0;
as->ioeventfds = NULL;
QTAILQ_INIT(&as->listeners);
--
2.11.0
- [Qemu-devel] [PATCH qemu v4 00/18] memory: Reduce memory use, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 01/18] exec: Explicitly export target AS from address_space_translate_internal, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 17/18] memory: Create FlatView directly, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 12/18] memory: Share FlatView's and dispatch trees between address spaces, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 13/18] memory: Do not allocate FlatView in address_space_init,
Alexey Kardashevskiy <=
- [Qemu-devel] [PATCH qemu v4 06/18] memory: Switch memory from using AddressSpace to FlatView, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 15/18] memory: Share special empty FlatView, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 02/18] memory: Open code FlatView rendering, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 10/18] memory: Alloc dispatch tree where topology is generared, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 08/18] memory: Rename mem_begin/mem_commit/mem_add helpers, Alexey Kardashevskiy, 2017/09/20
- [Qemu-devel] [PATCH qemu v4 09/18] memory: Store physical root MR in FlatView, Alexey Kardashevskiy, 2017/09/20