From 5bfc2be91ba382cf0c0353794ff9289cb9b064de Mon Sep 17 00:00:00 2001 From: David Gibson Date: Thu, 16 Nov 2017 03:07:26 +0100 Subject: [PATCH 22/30] memory: Do not allocate FlatView in address_space_init RH-Author: David Gibson Message-id: <20171116030732.8560-17-dgibson@redhat.com> Patchwork-id: 77705 O-Subject: [PATCH 16/22] memory: Do not allocate FlatView in address_space_init Bugzilla: 1481593 RH-Acked-by: Thomas Huth RH-Acked-by: Paolo Bonzini RH-Acked-by: Eduardo Habkost RH-Acked-by: Laurent Vivier From: Alexey Kardashevskiy 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 Message-Id: <20170921085110.25598-14-aik@ozlabs.ru> Signed-off-by: Paolo Bonzini (cherry picked from commit 67ace39b253ed5ae465275bc870f7e495547658b) Signed-off-by: David Gibson Signed-off-by: Miroslav Rezanina --- memory.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) diff --git a/memory.c b/memory.c index f0c8642..6914d87 100644 --- a/memory.c +++ b/memory.c @@ -966,22 +966,37 @@ 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 = { .nr = 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 @@ -989,7 +1004,9 @@ 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) @@ -2707,7 +2724,7 @@ 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); -- 1.8.3.1