{"id":816312,"url":"http://patchwork.ozlabs.org/api/patches/816312/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170920114637.42004-13-aik@ozlabs.ru/","project":{"id":14,"url":"http://patchwork.ozlabs.org/api/projects/14/?format=json","name":"QEMU Development","link_name":"qemu-devel","list_id":"qemu-devel.nongnu.org","list_email":"qemu-devel@nongnu.org","web_url":"","scm_url":"","webscm_url":"","list_archive_url":"","list_archive_url_format":"","commit_url_format":""},"msgid":"<20170920114637.42004-13-aik@ozlabs.ru>","list_archive_url":null,"date":"2017-09-20T11:46:31","name":"[qemu,v4,12/18] memory: Share FlatView's and dispatch trees between address spaces","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"72c6ef5011fa86ece5d400b83e057080e4dfe098","submitter":{"id":7621,"url":"http://patchwork.ozlabs.org/api/people/7621/?format=json","name":"Alexey Kardashevskiy","email":"aik@ozlabs.ru"},"delegate":null,"mbox":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170920114637.42004-13-aik@ozlabs.ru/mbox/","series":[{"id":4138,"url":"http://patchwork.ozlabs.org/api/series/4138/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=4138","date":"2017-09-20T11:46:20","name":"memory: Reduce memory use","version":4,"mbox":"http://patchwork.ozlabs.org/series/4138/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/816312/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/816312/checks/","tags":{},"related":[],"headers":{"Return-Path":"","X-Original-To":"incoming@patchwork.ozlabs.org","Delivered-To":"patchwork-incoming@bilbo.ozlabs.org","Authentication-Results":"ozlabs.org;\n\tspf=pass (mailfrom) smtp.mailfrom=nongnu.org\n\t(client-ip=2001:4830:134:3::11; helo=lists.gnu.org;\n\tenvelope-from=qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org;\n\treceiver=)","Received":["from lists.gnu.org (lists.gnu.org [IPv6:2001:4830:134:3::11])\n\t(using TLSv1 with cipher AES256-SHA (256/256 bits))\n\t(No client certificate requested)\n\tby ozlabs.org (Postfix) with ESMTPS id 3xy3f14T1jz9sPt\n\tfor ;\n\tThu, 21 Sep 2017 01:32:40 +1000 (AEST)","from localhost ([::1]:48895 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dugzO-000117-6L\n\tfor incoming@patchwork.ozlabs.org; Wed, 20 Sep 2017 11:32:38 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:56356)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dufmG-0003O4-Mb\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:15:02 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dufmD-00057G-6X\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:15:00 -0400","from ozlabs.ru ([107.173.13.209]:59738)\n\tby eggs.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dufmC-00056v-Ue\n\tfor qemu-devel@nongnu.org; Wed, 20 Sep 2017 10:14:57 -0400","from vpl1.ozlabs.ibm.com (localhost [IPv6:::1])\n\tby ozlabs.ru (Postfix) with ESMTP id 35BB03A6005B;\n\tWed, 20 Sep 2017 07:48:11 -0400 (EDT)"],"From":"Alexey Kardashevskiy ","To":"qemu-devel@nongnu.org","Date":"Wed, 20 Sep 2017 21:46:31 +1000","Message-Id":"<20170920114637.42004-13-aik@ozlabs.ru>","X-Mailer":"git-send-email 2.11.0","In-Reply-To":"<20170920114637.42004-1-aik@ozlabs.ru>","References":"<20170920114637.42004-1-aik@ozlabs.ru>","X-detected-operating-system":"by eggs.gnu.org: GNU/Linux 3.x [fuzzy]","X-Received-From":"107.173.13.209","Subject":"[Qemu-devel] [PATCH qemu v4 12/18] memory: Share FlatView's and\n\tdispatch trees between address spaces","X-BeenThere":"qemu-devel@nongnu.org","X-Mailman-Version":"2.1.21","Precedence":"list","List-Id":"","List-Unsubscribe":",\n\t","List-Archive":"","List-Post":"","List-Help":"","List-Subscribe":",\n\t","Cc":"Alexey Kardashevskiy , Paolo Bonzini ","Errors-To":"qemu-devel-bounces+incoming=patchwork.ozlabs.org@nongnu.org","Sender":"\"Qemu-devel\"\n\t"},"content":"This allows sharing flat views between address spaces (AS) when\nthe same root memory region is used when creating a new address space.\nThis is done by walking through all ASes and caching one FlatView per\na physical root MR (i.e. not aliased).\n\nThis removes search for duplicates from address_space_init_shareable() as\nFlatViews are shared elsewhere and keeping as::ref_count correct seems\nan unnecessary and useless complication.\n\nThis should cause no change and memory use or boot time yet.\n\nSigned-off-by: Alexey Kardashevskiy \n---\nChanges:\nv4:\n* used g_hash_table_new_full() instead of g_hash_table_new() +\ng_hash_table_foreach_remove()\n* cached last hash table of FV globally\n\nv3:\n* got rid of global and per-AS lists of FlatView objects\n---\n memory.c | 57 ++++++++++++++++++++++++++++++++++++++++++++++-----------\n 1 file changed, 46 insertions(+), 11 deletions(-)","diff":"diff --git a/memory.c b/memory.c\nindex 9868d0f57c..1083fe9130 100644\n--- a/memory.c\n+++ b/memory.c\n@@ -47,6 +47,8 @@ static QTAILQ_HEAD(memory_listeners, MemoryListener) memory_listeners\n static QTAILQ_HEAD(, AddressSpace) address_spaces\n = QTAILQ_HEAD_INITIALIZER(address_spaces);\n \n+static GHashTable *flat_views;\n+\n typedef struct AddrRange AddrRange;\n \n /*\n@@ -925,11 +927,49 @@ static void address_space_update_topology_pass(AddressSpace *as,\n }\n }\n \n-static void address_space_update_topology(AddressSpace *as)\n+static void flatviews_init(void)\n+{\n+ if (flat_views) {\n+ return;\n+ }\n+\n+ flat_views = g_hash_table_new_full(g_direct_hash, g_direct_equal, NULL,\n+ (GDestroyNotify) flatview_unref);\n+}\n+\n+static void flatviews_reset(void)\n+{\n+ AddressSpace *as;\n+\n+ if (flat_views) {\n+ g_hash_table_unref(flat_views);\n+ flat_views = NULL;\n+ }\n+ flatviews_init();\n+\n+ /* Render unique FVs */\n+ QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {\n+ MemoryRegion *physmr = memory_region_get_flatview_root(as->root);\n+ FlatView *new_view = g_hash_table_lookup(flat_views, physmr);\n+\n+ if (new_view) {\n+ continue;\n+ }\n+\n+ new_view = generate_memory_topology(physmr);\n+ g_hash_table_insert(flat_views, physmr, new_view);\n+ }\n+}\n+\n+static void flatview_set_to_address_space(AddressSpace *as)\n {\n FlatView *old_view = address_space_get_flatview(as);\n- MemoryRegion *physmr = memory_region_get_flatview_root(old_view->root);\n- FlatView *new_view = generate_memory_topology(physmr);\n+ MemoryRegion *physmr = memory_region_get_flatview_root(as->root);\n+ FlatView *new_view = g_hash_table_lookup(flat_views, physmr);\n+\n+ assert(new_view);\n+\n+ flatview_ref(new_view);\n \n if (!QTAILQ_EMPTY(&as->listeners)) {\n address_space_update_topology_pass(as, old_view, new_view, false);\n@@ -965,10 +1005,12 @@ void memory_region_transaction_commit(void)\n --memory_region_transaction_depth;\n if (!memory_region_transaction_depth) {\n if (memory_region_update_pending) {\n+ flatviews_reset();\n+\n MEMORY_LISTENER_CALL_GLOBAL(begin, Forward);\n \n QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {\n- address_space_update_topology(as);\n+ flatview_set_to_address_space(as);\n address_space_update_ioeventfds(as);\n }\n memory_region_update_pending = false;\n@@ -2691,13 +2733,6 @@ AddressSpace *address_space_init_shareable(MemoryRegion *root, const char *name)\n {\n AddressSpace *as;\n \n- QTAILQ_FOREACH(as, &address_spaces, address_spaces_link) {\n- if (root == as->root && as->malloced) {\n- as->ref_count++;\n- return as;\n- }\n- }\n-\n as = g_malloc0(sizeof *as);\n address_space_init(as, root, name);\n as->malloced = true;\n","prefixes":["qemu","v4","12/18"]}