memory: Create FlatView directly

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 <aik@ozlabs.ru>
Message-Id: <20170921085110.25598-18-aik@ozlabs.ru>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
This commit is contained in:
Alexey Kardashevskiy 2017-09-21 18:51:09 +10:00 committed by Paolo Bonzini
parent b516572f31
commit 202fc01b05

View File

@ -1010,6 +1010,17 @@ 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();
@ -2721,7 +2732,6 @@ 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;
@ -2729,8 +2739,8 @@ 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);
address_space_update_ioeventfds(as);
}
static void do_address_space_destroy(AddressSpace *as)