Messages in this thread | | | Date | Wed, 18 Apr 2012 03:30:31 +0000 | From | "Serge E. Hallyn" <> | Subject | Re: [Patch 7/8] mqueue: separate mqueue default value from maximum value v2 |
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Quoting Doug Ledford (dledford@redhat.com): > From: KOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com> > > 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 <kosaki.motohiro@jp.fujitsu.com> > Acked-by: Doug Ledford <dledford@redhat.com> > Acked-by: Joe Korty <joe.korty@ccur.com> > Cc: Amerigo Wang <amwang@redhat.com> > Cc: Serge E. Hallyn <serue@us.ibm.com>
Seems reasonable. Thanks.
Acked-by: Serge E. Hallyn <serge.hallyn@canonical.com>
> Cc: Jiri Slaby <jslaby@suse.cz> > > v1->v2: Slightly modified because msgutil.c no longer needs mq > namespace initialization > > Signed-off-by (v2): Doug Ledford <dledford@redhat.com> > --- > Documentation/sysctl/fs.txt | 7 +++++++ > include/linux/ipc_namespace.h | 2 ++ > ipc/mq_sysctl.c | 18 ++++++++++++++++++ > ipc/mqueue.c | 9 ++++++--- > 4 files changed, 33 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 2488535..5499c92 100644 > --- a/include/linux/ipc_namespace.h > +++ b/include/linux/ipc_namespace.h > @@ -62,6 +62,8 @@ struct ipc_namespace { > unsigned int mq_queues_max; /* initialized to DFLT_QUEUESMAX */ > 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;
Mention here what they are initialized to, for completeness?
> > /* 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 f9f0782..04cc77e 100644 > --- a/ipc/mqueue.c > +++ b/ipc/mqueue.c > @@ -142,9 +142,10 @@ 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; > @@ -1254,6 +1255,8 @@ 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)) { > -- > 1.7.7.6 > > -- > To unsubscribe from this list: send the line "unsubscribe linux-kernel" in > the body of a message to majordomo@vger.kernel.org > More majordomo info at http://vger.kernel.org/majordomo-info.html > Please read the FAQ at http://www.tux.org/lkml/
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