From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48524) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1duxCs-00056z-AN for qemu-devel@nongnu.org; Thu, 21 Sep 2017 04:51:39 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1duxCp-0001Jd-Tc for qemu-devel@nongnu.org; Thu, 21 Sep 2017 04:51:37 -0400 Received: from ozlabs.ru ([107.173.13.209]:54112) by eggs.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1duxCp-0001CA-NQ for qemu-devel@nongnu.org; Thu, 21 Sep 2017 04:51:35 -0400 From: Alexey Kardashevskiy Date: Thu, 21 Sep 2017 18:51:05 +1000 Message-Id: <20170921085110.25598-14-aik@ozlabs.ru> In-Reply-To: <20170921085110.25598-1-aik@ozlabs.ru> References: <20170921085110.25598-1-aik@ozlabs.ru> Subject: [Qemu-devel] [PATCH qemu v5 13/18] memory: Do not allocate FlatView in address_space_init List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , To: qemu-devel@nongnu.org Cc: Alexey Kardashevskiy , Paolo Bonzini 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 --- 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