{"id":814862,"url":"http://patchwork.ozlabs.org/api/patches/814862/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/patch/20170918101709.30421-2-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":"<20170918101709.30421-2-aik@ozlabs.ru>","list_archive_url":null,"date":"2017-09-18T10:16:57","name":"[qemu,v3,01/13] memory: Postpone flatview and dispatch tree building till all devices are added","commit_ref":null,"pull_url":null,"state":"new","archived":false,"hash":"cbc3563d22f7e89916801b0a42820db08d4d5091","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/20170918101709.30421-2-aik@ozlabs.ru/mbox/","series":[{"id":3617,"url":"http://patchwork.ozlabs.org/api/series/3617/?format=json","web_url":"http://patchwork.ozlabs.org/project/qemu-devel/list/?series=3617","date":"2017-09-18T10:16:57","name":"memory: Reduce memory use","version":3,"mbox":"http://patchwork.ozlabs.org/series/3617/mbox/"}],"comments":"http://patchwork.ozlabs.org/api/patches/814862/comments/","check":"pending","checks":"http://patchwork.ozlabs.org/api/patches/814862/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 3xwhmC389wz9s78\n\tfor ;\n\tMon, 18 Sep 2017 20:18:19 +1000 (AEST)","from localhost ([::1]:35586 helo=lists.gnu.org)\n\tby lists.gnu.org with esmtp (Exim 4.71) (envelope-from\n\t)\n\tid 1dtt85-0005lb-Bc\n\tfor incoming@patchwork.ozlabs.org; Mon, 18 Sep 2017 06:18:17 -0400","from eggs.gnu.org ([2001:4830:134:3::10]:41941)\n\tby lists.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dtt7E-0005i5-TM\n\tfor qemu-devel@nongnu.org; Mon, 18 Sep 2017 06:17:29 -0400","from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71)\n\t(envelope-from ) id 1dtt7A-0004DP-IP\n\tfor qemu-devel@nongnu.org; Mon, 18 Sep 2017 06:17:24 -0400","from ozlabs.ru ([107.173.13.209]:35230)\n\tby eggs.gnu.org with esmtp (Exim 4.71)\n\t(envelope-from ) id 1dtt7A-0004Bn-CE\n\tfor qemu-devel@nongnu.org; Mon, 18 Sep 2017 06:17:20 -0400","from vpl1.ozlabs.ibm.com (localhost [IPv6:::1])\n\tby ozlabs.ru (Postfix) with ESMTP id 3DB083A6002B;\n\tMon, 18 Sep 2017 06:18:33 -0400 (EDT)"],"From":"Alexey Kardashevskiy ","To":"qemu-devel@nongnu.org","Date":"Mon, 18 Sep 2017 20:16:57 +1000","Message-Id":"<20170918101709.30421-2-aik@ozlabs.ru>","X-Mailer":"git-send-email 2.11.0","In-Reply-To":"<20170918101709.30421-1-aik@ozlabs.ru>","References":"<20170918101709.30421-1-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 v3 01/13] memory: Postpone flatview and\n\tdispatch tree building till all devices are added","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":"Most devices use at least one address space and every time a new address\nspace is added, flat views and dispatch trees are rebuild for all address\nspaces. This is not a problem for a relatively small amount of devices but\neven 50 virtio-pci devices use more than 8GB of RAM.\n\nWhat happens that on every flatview/dispatch rebuild, new arrays are\nallocated and old ones release but the release is done via RCU so until\nan entire machine is build, they are not released.\n\nThis wraps devices creation into memory_region_transaction_begin/commit\nto massively reduce amount of flat view/dispatch tree (re)allocations.\n\nSigned-off-by: Alexey Kardashevskiy \n---\nChanges:\nv2:\n* wrapped qemu_run_machine_init_done_notifiers() as well\n---\n vl.c | 9 +++++++++\n 1 file changed, 9 insertions(+)","diff":"diff --git a/vl.c b/vl.c\nindex 9e62e92aea..e4f2ece590 100644\n--- a/vl.c\n+++ b/vl.c\n@@ -4741,12 +4741,16 @@ int main(int argc, char **argv, char **envp)\n igd_gfx_passthru();\n \n /* init generic devices */\n+ memory_region_transaction_begin();\n+\n rom_set_order_override(FW_CFG_ORDER_OVERRIDE_DEVICE);\n if (qemu_opts_foreach(qemu_find_opts(\"device\"),\n device_init_func, NULL, NULL)) {\n exit(1);\n }\n \n+ memory_region_transaction_commit();\n+\n cpu_synchronize_all_post_init();\n \n rom_reset_order_override();\n@@ -4829,8 +4833,13 @@ int main(int argc, char **argv, char **envp)\n /* TODO: once all bus devices are qdevified, this should be done\n * when bus is created by qdev.c */\n qemu_register_reset(qbus_reset_all_fn, sysbus_get_default());\n+\n+ memory_region_transaction_begin();\n+\n qemu_run_machine_init_done_notifiers();\n \n+ memory_region_transaction_commit();\n+\n if (rom_check_and_register_reset() != 0) {\n error_report(\"rom check and register reset failed\");\n exit(1);\n","prefixes":["qemu","v3","01/13"]}