From mboxrd@z Thu Jan 1 00:00:00 1970 Received: from eggs.gnu.org ([2001:4830:134:3::10]:48922) by lists.gnu.org with esmtp (Exim 4.71) (envelope-from ) id 1eMfCB-0000Hl-1b for qemu-devel@nongnu.org; Wed, 06 Dec 2017 14:17:28 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1eMfC8-0000Ju-Qx for qemu-devel@nongnu.org; Wed, 06 Dec 2017 14:17:27 -0500 Received: from mx0a-001b2d01.pphosted.com ([148.163.156.1]:40968) by eggs.gnu.org with esmtps (TLS1.0:RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1eMfC8-0000IG-Jh for qemu-devel@nongnu.org; Wed, 06 Dec 2017 14:17:24 -0500 Received: from pps.filterd (m0098404.ppops.net [127.0.0.1]) by mx0a-001b2d01.pphosted.com (8.16.0.21/8.16.0.21) with SMTP id vB6JEvHh076143 for ; Wed, 6 Dec 2017 14:17:22 -0500 Received: from e37.co.us.ibm.com (e37.co.us.ibm.com [32.97.110.158]) by mx0a-001b2d01.pphosted.com with ESMTP id 2epmmmnn67-1 (version=TLSv1.2 cipher=AES256-SHA bits=256 verify=NOT) for ; Wed, 06 Dec 2017 14:17:22 -0500 Received: from localhost by e37.co.us.ibm.com with IBM ESMTP SMTP Gateway: Authorized Use Only! Violators will be prosecuted for from ; Wed, 6 Dec 2017 12:17:21 -0700 From: Michael Roth Date: Wed, 6 Dec 2017 13:16:12 -0600 In-Reply-To: <20171206191648.18208-1-mdroth@linux.vnet.ibm.com> References: <20171206191648.18208-1-mdroth@linux.vnet.ibm.com> Message-Id: <20171206191648.18208-20-mdroth@linux.vnet.ibm.com> Subject: [Qemu-devel] [PATCH 19/55] 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: qemu-stable@nongnu.org, Alexey Kardashevskiy , Paolo Bonzini 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: Michael Roth --- memory.c | 29 +++++++++++++++++++++++------ 1 file changed, 23 insertions(+), 6 deletions(-) diff --git a/memory.c b/memory.c index f0c864206a..6914d87d0d 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); -- 2.11.0