This avoids usual memory_region_transaction_commit() which rebuilds all FVs.
On POWER8 with 255 CPUs, 255 virtio-net, 40 PCI bridges guest this brings down the boot time from 25s to 20s and reduces the amount of temporary FVs allocated during machine constructon (~800000 -> ~640000) and amount of temporary dispatch trees (~370000 -> ~300000), the total memory footprint goes down (18G -> 17G). Signed-off-by: Alexey Kardashevskiy <a...@ozlabs.ru> --- Changes: v5: * %s/flatview_update_topology_single/address_space_update_topology/g * fixup after moving g_hash_table_replace() to generate_memory_topology() --- memory.c | 15 ++++++++++++--- 1 file changed, 12 insertions(+), 3 deletions(-) diff --git a/memory.c b/memory.c index 57e47e990f..5c21563745 100644 --- a/memory.c +++ b/memory.c @@ -1027,6 +1027,17 @@ static void address_space_set_flatview(AddressSpace *as) } } +static void address_space_update_topology(AddressSpace *as) +{ + MemoryRegion *physmr = memory_region_get_flatview_root(as->root); + + flatviews_init(); + if (!g_hash_table_lookup(flat_views, physmr)) { + generate_memory_topology(physmr); + } + address_space_set_flatview(as); +} + void memory_region_transaction_begin(void) { qemu_flush_coalesced_mmio_buffer(); @@ -2738,7 +2749,6 @@ void memory_region_invalidate_mmio_ptr(MemoryRegion *mr, hwaddr offset, void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name) { memory_region_ref(root); - memory_region_transaction_begin(); as->root = root; as->current_map = NULL; as->ioeventfd_nb = 0; @@ -2746,8 +2756,7 @@ void address_space_init(AddressSpace *as, MemoryRegion *root, const char *name) QTAILQ_INIT(&as->listeners); QTAILQ_INSERT_TAIL(&address_spaces, as, address_spaces_link); as->name = g_strdup(name ? name : "anonymous"); - memory_region_update_pending |= root->enabled; - memory_region_transaction_commit(); + address_space_update_topology(as); } static void do_address_space_destroy(AddressSpace *as) -- 2.11.0