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authorKOSAKI Motohiro <kosaki.motohiro@jp.fujitsu.com>2012-05-31 16:26:33 -0700
committerLinus Torvalds <torvalds@linux-foundation.org>2012-05-31 17:49:31 -0700
commitcef0184c115e5e4e10498f6548d9526465e72478 (patch)
tree752c4116e0f93328239db9ff2c2ed730fef3ce0e
parentfd1f87d24d492fda464bedf10a5dd5174ff9b065 (diff)
downloadlinux-stericsson-cef0184c115e5e4e10498f6548d9526465e72478.tar.gz
mqueue: separate mqueue default value from maximum value
Commit b231cca4381e ("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> Signed-off-by: Doug Ledford <dledford@redhat.com> Acked-by: Doug Ledford <dledford@redhat.com> Acked-by: Joe Korty <joe.korty@ccur.com> Cc: Amerigo Wang <amwang@redhat.com> Acked-by: Serge E. Hallyn <serue@us.ibm.com> Cc: Jiri Slaby <jslaby@suse.cz> Cc: Manfred Spraul <manfred@colorfullife.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
-rw-r--r--Documentation/sysctl/fs.txt7
-rw-r--r--include/linux/ipc_namespace.h2
-rw-r--r--ipc/mq_sysctl.c18
-rw-r--r--ipc/mqueue.c9
4 files changed, 33 insertions, 3 deletions
diff --git a/Documentation/sysctl/fs.txt b/Documentation/sysctl/fs.txt
index 88fd7f5c8dcd..13d6166d7a27 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 2488535a32a3..5499c92a9153 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;
/* 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 e22336a09b4a..383d638340b8 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 6828e2c93cef..609d53f7a915 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -145,9 +145,10 @@ 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;
@@ -1261,6 +1262,8 @@ 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)) {