From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S933559Ab1JZPhm (ORCPT ); Wed, 26 Oct 2011 11:37:42 -0400 Received: from mail-vx0-f174.google.com ([209.85.220.174]:56421 "EHLO mail-vx0-f174.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S933299Ab1JZPhj (ORCPT ); Wed, 26 Oct 2011 11:37:39 -0400 Message-ID: <4EA8297B.6020403@gmail.com> Date: Wed, 26 Oct 2011 11:38:35 -0400 From: KOSAKI Motohiro User-Agent: Mozilla/5.0 (Windows NT 5.1; rv:7.0.1) Gecko/20110929 Thunderbird/7.0.1 MIME-Version: 1.0 To: dledford@redhat.com CC: akpm@linux-foundation.org, torvalds@linux-foundation.org, linux-kernel@vger.kernel.org, joe.korty@ccur.com, amwang@redhat.com Subject: [PATCH 7/4] ipc/mqueue: separate mqueue default value from maximum value References: <1317162613-11060-1-git-send-email-dledford@redhat.com> <1317162613-11060-3-git-send-email-dledford@redhat.com> <4EA828E4.1070409@gmail.com> In-Reply-To: <4EA828E4.1070409@gmail.com> Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org commit b231cca438 (message queues: increase range limits) changed mqueue default value when attr parameter is specified NULL from hard coded value to fs.mqueue.{msg,msgsize}_max sysctl value. This made large side effect. When user need to use two mqueue applications 1) using !NULL attr parameter and it require big message size and 2) using NULL attr parameter and only need small size message, app (1) require to raise fs.mqueue.msgsize_max and app (2) consume large memory size even though it doesn't need. Doug Ledford propsed to switch back it to static hard coded value. However it also has a compatibility problem. Some applications might started depend on the default value is tunable. The solution is to separate default value from maximum value. Signed-off-by: KOSAKI Motohiro Cc: Doug Ledford Cc: Amerigo Wang Cc: Serge E. Hallyn Cc: Jiri Slaby Cc: Joe Korty --- Documentation/sysctl/fs.txt | 7 +++++++ include/linux/ipc_namespace.h | 3 +++ ipc/mq_sysctl.c | 18 ++++++++++++++++++ ipc/mqueue.c | 9 ++++++--- ipc/msgutil.c | 2 ++ 5 files changed, 36 insertions(+), 3 deletions(-) diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt index 88fd7f5..13d6166 100644 --- a/Documentation/sysctl/fs.txt +++ b/Documentation/sysctl/fs.txt @@ -225,6 +225,13 @@ a queue must be less or equal then msg_max. maximum message size value (it is every message queue's attribute set during its creation). +/proc/sys/fs/mqueue/msg_default is a read/write file for setting/getting the +default number of messages in a queue value if attr parameter of mq_open(2) is +NULL. If it exceed msg_max, the default value is initialized msg_max. + +/proc/sys/fs/mqueue/msgsize_default is a read/write file for setting/getting +the default message size value if attr parameter of mq_open(2) is NULL. If it +exceed msgsize_max, the default value is initialized msgsize_max. 4. /proc/sys/fs/epoll - Configuration options for the epoll interface -------------------------------------------------------- diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h index 2d7c5e0..9e25a33 100644 --- a/include/linux/ipc_namespace.h +++ b/include/linux/ipc_namespace.h @@ -63,6 +63,9 @@ struct ipc_namespace { unsigned int mq_msg_max; /* initialized to DFLT_MSGMAX */ unsigned int mq_msgsize_max; /* initialized to DFLT_MSGSIZEMAX */ + unsigned int mq_msg_default; + unsigned int mq_msgsize_default; + /* user_ns which owns the ipc ns */ struct user_namespace *user_ns; }; diff --git a/ipc/mq_sysctl.c b/ipc/mq_sysctl.c index e22336a..383d638 100644 --- a/ipc/mq_sysctl.c +++ b/ipc/mq_sysctl.c @@ -73,6 +73,24 @@ static ctl_table mq_sysctls[] = { .extra1 = &msg_maxsize_limit_min, .extra2 = &msg_maxsize_limit_max, }, + { + .procname = "msg_default", + .data = &init_ipc_ns.mq_msg_default, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec_minmax, + .extra1 = &msg_max_limit_min, + .extra2 = &msg_max_limit_max, + }, + { + .procname = "msgsize_default", + .data = &init_ipc_ns.mq_msgsize_default, + .maxlen = sizeof(int), + .mode = 0644, + .proc_handler = proc_mq_dointvec_minmax, + .extra1 = &msg_maxsize_limit_min, + .extra2 = &msg_maxsize_limit_max, + }, {} }; diff --git a/ipc/mqueue.c b/ipc/mqueue.c index 91ca145..f762fe6 100644 --- a/ipc/mqueue.c +++ b/ipc/mqueue.c @@ -143,9 +143,10 @@ static struct inode *mqueue_get_inode(struct super_block *sb, info->qsize = 0; info->user = NULL; /* set when all is ok */ memset(&info->attr, 0, sizeof(info->attr)); - info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, DFLT_MSG); - info->attr.mq_msgsize = - min(ipc_ns->mq_msgsize_max, DFLT_MSGSIZE); + info->attr.mq_maxmsg = min(ipc_ns->mq_msg_max, + ipc_ns->mq_msg_default); + info->attr.mq_msgsize = min(ipc_ns->mq_msgsize_max, + ipc_ns->mq_msgsize_default); if (attr) { info->attr.mq_maxmsg = attr->mq_maxmsg; info->attr.mq_msgsize = attr->mq_msgsize; @@ -1262,6 +1263,8 @@ int mq_init_ns(struct ipc_namespace *ns) ns->mq_queues_max = DFLT_QUEUESMAX; ns->mq_msg_max = DFLT_MSGMAX; ns->mq_msgsize_max = DFLT_MSGSIZEMAX; + ns->mq_msg_default = DFLT_MSG; + ns->mq_msgsize_default = DFLT_MSGSIZE; ns->mq_mnt = kern_mount_data(&mqueue_fs_type, ns); if (IS_ERR(ns->mq_mnt)) { diff --git a/ipc/msgutil.c b/ipc/msgutil.c index 8b5ce5d3..a344216 100644 --- a/ipc/msgutil.c +++ b/ipc/msgutil.c @@ -31,6 +31,8 @@ struct ipc_namespace init_ipc_ns = { .mq_queues_max = DFLT_QUEUESMAX, .mq_msg_max = DFLT_MSGMAX, .mq_msgsize_max = DFLT_MSGSIZEMAX, + .mq_msg_default = DFLT_MSG, + .mq_msgsize_default = DFLT_MSGSIZE, #endif .user_ns = &init_user_ns, }; -- 1.7.5.2