kernel-ark/ipc/mq_sysctl.c
Davidlohr Bueso f3713fd9cf ipc,mqueue: remove limits for the amount of system-wide queues
Commit 93e6f119c0 ("ipc/mqueue: cleanup definition names and
locations") added global hardcoded limits to the amount of message
queues that can be created.  While these limits are per-namespace,
reality is that it ends up breaking userspace applications.
Historically users have, at least in theory, been able to create up to
INT_MAX queues, and limiting it to just 1024 is way too low and dramatic
for some workloads and use cases.  For instance, Madars reports:

 "This update imposes bad limits on our multi-process application.  As
  our app uses approaches that each process opens its own set of queues
  (usually something about 3-5 queues per process).  In some scenarios
  we might run up to 3000 processes or more (which of-course for linux
  is not a problem).  Thus we might need up to 9000 queues or more.  All
  processes run under one user."

Other affected users can be found in launchpad bug #1155695:
  https://bugs.launchpad.net/ubuntu/+source/manpages/+bug/1155695

Instead of increasing this limit, revert it entirely and fallback to the
original way of dealing queue limits -- where once a user's resource
limit is reached, and all memory is used, new queues cannot be created.

Signed-off-by: Davidlohr Bueso <davidlohr@hp.com>
Reported-by: Madars Vitolins <m@silodev.com>
Acked-by: Doug Ledford <dledford@redhat.com>
Cc: Manfred Spraul <manfred@colorfullife.com>
Cc: <stable@vger.kernel.org>	[3.5+]
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2014-02-25 15:25:45 -08:00

125 lines
2.9 KiB
C

/*
* Copyright (C) 2007 IBM Corporation
*
* Author: Cedric Le Goater <clg@fr.ibm.com>
*
* This program is free software; you can redistribute it and/or
* modify it under the terms of the GNU General Public License as
* published by the Free Software Foundation, version 2 of the
* License.
*/
#include <linux/nsproxy.h>
#include <linux/ipc_namespace.h>
#include <linux/sysctl.h>
#ifdef CONFIG_PROC_SYSCTL
static void *get_mq(ctl_table *table)
{
char *which = table->data;
struct ipc_namespace *ipc_ns = current->nsproxy->ipc_ns;
which = (which - (char *)&init_ipc_ns) + (char *)ipc_ns;
return which;
}
static int proc_mq_dointvec(ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table mq_table;
memcpy(&mq_table, table, sizeof(mq_table));
mq_table.data = get_mq(table);
return proc_dointvec(&mq_table, write, buffer, lenp, ppos);
}
static int proc_mq_dointvec_minmax(ctl_table *table, int write,
void __user *buffer, size_t *lenp, loff_t *ppos)
{
struct ctl_table mq_table;
memcpy(&mq_table, table, sizeof(mq_table));
mq_table.data = get_mq(table);
return proc_dointvec_minmax(&mq_table, write, buffer,
lenp, ppos);
}
#else
#define proc_mq_dointvec NULL
#define proc_mq_dointvec_minmax NULL
#endif
static int msg_max_limit_min = MIN_MSGMAX;
static int msg_max_limit_max = HARD_MSGMAX;
static int msg_maxsize_limit_min = MIN_MSGSIZEMAX;
static int msg_maxsize_limit_max = HARD_MSGSIZEMAX;
static ctl_table mq_sysctls[] = {
{
.procname = "queues_max",
.data = &init_ipc_ns.mq_queues_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_mq_dointvec,
},
{
.procname = "msg_max",
.data = &init_ipc_ns.mq_msg_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_mq_dointvec_minmax,
.extra1 = &msg_max_limit_min,
.extra2 = &msg_max_limit_max,
},
{
.procname = "msgsize_max",
.data = &init_ipc_ns.mq_msgsize_max,
.maxlen = sizeof(int),
.mode = 0644,
.proc_handler = proc_mq_dointvec_minmax,
.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,
},
{}
};
static ctl_table mq_sysctl_dir[] = {
{
.procname = "mqueue",
.mode = 0555,
.child = mq_sysctls,
},
{}
};
static ctl_table mq_sysctl_root[] = {
{
.procname = "fs",
.mode = 0555,
.child = mq_sysctl_dir,
},
{}
};
struct ctl_table_header *mq_register_sysctl_table(void)
{
return register_sysctl_table(mq_sysctl_root);
}