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[Qemu-devel] [PATCH qemu v5 13/18] memory: Do not allocate FlatView in a
From: |
Alexey Kardashevskiy |
Subject: |
[Qemu-devel] [PATCH qemu v5 13/18] memory: Do not allocate FlatView in address_space_init |
Date: |
Thu, 21 Sep 2017 18:51:05 +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 56b3dd47ab..c623575dac 100644
--- a/memory.c
+++ b/memory.c
@@ -962,22 +962,37 @@ static void flatviews_reset(void)
static void address_space_set_flatview(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
@@ -985,7 +1000,9 @@ static void address_space_set_flatview(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)
@@ -2703,7 +2720,7 @@ 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 v5 04/18] memory: Move AddressSpaceDispatch from AddressSpace to FlatView, (continued)
- [Qemu-devel] [PATCH qemu v5 07/18] memory: Cleanup after switching to FlatView, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 09/18] memory: Store physical root MR in FlatView, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 06/18] memory: Switch memory from using AddressSpace to FlatView, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 12/18] memory: Share FlatView's and dispatch trees between address spaces, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 08/18] memory: Rename mem_begin/mem_commit/mem_add helpers, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 11/18] memory: Move address_space_update_ioeventfds, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 13/18] memory: Do not allocate FlatView in address_space_init,
Alexey Kardashevskiy <=
- [Qemu-devel] [PATCH qemu v5 10/18] memory: Alloc dispatch tree where topology is generared, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 18/18] memory: Avoid temporary FlatView allocation in a single child case, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 14/18] memory: Rework "info mtree" to print flat views and dispatch trees, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 15/18] memory: Share special empty FlatView, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 16/18] memory: Get rid of address_space_init_shareable, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 17/18] memory: Create FlatView directly, Alexey Kardashevskiy, 2017/09/21
- [Qemu-devel] [PATCH qemu v5 01/18] exec: Explicitly export target AS from address_space_translate_internal, Alexey Kardashevskiy, 2017/09/21
- Re: [Qemu-devel] [PATCH qemu v5 00/18] memory: Store physical root MR in FlatView, Paolo Bonzini, 2017/09/21