[PATCH 0/3] ipc: Further updates to sysv/mqueue limits

[PATCH 0/3] ipc: Further updates to sysv/mqueue limits

[Manfred Spraul]

Hi all,

a) If we increase SHMMAX/SHMALL, then it makes sense to
   increase MSGMNI, too.
   And: This allows to remove the automatic scaling (~300 lines)

b) We can also increase SEMMSL, SEMMNI and SEMOPM

c) I think it would make more sense if a namespace starts with the
   limits from it's parent:
   If an admin set the limits, then he probably wants that these limits also
   apply for a new child namespace.

All patches are RFC - they compile, but that's it.

TODO:
- check if the sysv sem limits are sane.
  Especially the SEMOPM - if real users exist that pass > 1k ops, then
  switch from kmalloc to vmalloc.

  @the Redhat developers: Do you have any idea where this "often
  recommended" comes from?
  https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Tuning_and_Optimizing_Red_Hat_Enterprise_Linux_for_Oracle_9i_and_10g_Databases/sect-Oracle_9i_and_10g_Tuning_Guide-Setting_Semaphores-The_SEMOPM_Parameter.html

- copy Davidlohrs explanation for the sysv shm limits to sysv msg and
  sysv sem.

- check if we should also increase the limits for posix mqueue

- decide if it would make sense to increase IPCMNI:

  Right now, it is 32768. This means that after 65536 pairs of
  semget()/semctl(IPC_RMID), semget() will return the same identifier
  again - and a semop(old_id) won't return -EINVAL, instead it will
  access the "new" array, which is probably now what the caller
  intended to do.

  The split is arbitrary - we could also split it 1048576/2048 or any
  other split we want.

- test everything.

--
	Manfred

[PATCH 1/3] ipc/msg: increase MSGMNI, remove scaling

[Manfred Spraul]

SysV can be abused to allocated locked kernel memory.
For most systems, a small limit doesn't make sense,
see the discussion with regards to SHMMAX.

Therefore: increase MSGMNI to the maximum supported.

And: if we ignore the risk of locking too much memory, then
an automatic scaling of MSGMNI doesn't make sense.

Therefore: remove the whole logic.

Note:
If an administrator must limit the memory allocations, then
he can set MSGMNI as necessary.

Or he can disable sysv entirely (as e.g. done with Android).
---
 include/linux/ipc_namespace.h | 20 ----------
 include/uapi/linux/msg.h      | 12 +-----
 ipc/Makefile                  |  2 +-
 ipc/ipc_sysctl.c              | 87 +---------------------------------------
 ipc/ipcns_notifier.c          | 92 -------------------------------------------
 ipc/msg.c                     | 36 +----------------
 ipc/namespace.c               | 22 -----------
 ipc/util.c                    | 40 -------------------
 8 files changed, 4 insertions(+), 307 deletions(-)
 delete mode 100644 ipc/ipcns_notifier.c

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index 35e7eca..e365d5e 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -7,15 +7,6 @@
 #include <linux/notifier.h>
 #include <linux/nsproxy.h>
 
-/*
- * ipc namespace events
- */
-#define IPCNS_MEMCHANGED   0x00000001   /* Notify lowmem size changed */
-#define IPCNS_CREATED  0x00000002   /* Notify new ipc namespace created */
-#define IPCNS_REMOVED  0x00000003   /* Notify ipc namespace removed */
-
-#define IPCNS_CALLBACK_PRI 0
-
 struct user_namespace;
 
 struct ipc_ids {
@@ -38,7 +29,6 @@ struct ipc_namespace {
 	unsigned int	msg_ctlmni;
 	atomic_t	msg_bytes;
 	atomic_t	msg_hdrs;
-	int		auto_msgmni;
 
 	size_t		shm_ctlmax;
 	size_t		shm_ctlall;
@@ -77,18 +67,8 @@ extern atomic_t nr_ipc_ns;
 extern spinlock_t mq_lock;
 
 #ifdef CONFIG_SYSVIPC
-extern int register_ipcns_notifier(struct ipc_namespace *);
-extern int cond_register_ipcns_notifier(struct ipc_namespace *);
-extern void unregister_ipcns_notifier(struct ipc_namespace *);
-extern int ipcns_notify(unsigned long);
 extern void shm_destroy_orphaned(struct ipc_namespace *ns);
 #else /* CONFIG_SYSVIPC */
-static inline int register_ipcns_notifier(struct ipc_namespace *ns)
-{ return 0; }
-static inline int cond_register_ipcns_notifier(struct ipc_namespace *ns)
-{ return 0; }
-static inline void unregister_ipcns_notifier(struct ipc_namespace *ns) { }
-static inline int ipcns_notify(unsigned long l) { return 0; }
 static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
 #endif /* CONFIG_SYSVIPC */
 
diff --git a/include/uapi/linux/msg.h b/include/uapi/linux/msg.h
index a703755..ae9ddd2 100644
--- a/include/uapi/linux/msg.h
+++ b/include/uapi/linux/msg.h
@@ -50,17 +50,7 @@ struct msginfo {
 	unsigned short  msgseg; 
 };
 
-/*
- * Scaling factor to compute msgmni:
- * the memory dedicated to msg queues (msgmni * msgmnb) should occupy
- * at most 1/MSG_MEM_SCALE of the lowmem (see the formula in ipc/msg.c):
- * up to 8MB       : msgmni = 16 (MSGMNI)
- * 4 GB            : msgmni = 8K
- * more than 16 GB : msgmni = 32K (IPCMNI)
- */
-#define MSG_MEM_SCALE 32
-
-#define MSGMNI    16   /* <= IPCMNI */     /* max # of msg queue identifiers */
+#define MSGMNI 32000   /* <= IPCMNI */     /* max # of msg queue identifiers */
 #define MSGMAX  8192   /* <= INT_MAX */   /* max size of message (bytes) */
 #define MSGMNB 16384   /* <= INT_MAX */   /* default max size of a message queue */
 
diff --git a/ipc/Makefile b/ipc/Makefile
index 9075e17..86c7300 100644
--- a/ipc/Makefile
+++ b/ipc/Makefile
@@ -3,7 +3,7 @@
 #
 
 obj-$(CONFIG_SYSVIPC_COMPAT) += compat.o
-obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o ipcns_notifier.o syscall.o
+obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o syscall.o
 obj-$(CONFIG_SYSVIPC_SYSCTL) += ipc_sysctl.o
 obj_mq-$(CONFIG_COMPAT) += compat_mq.o
 obj-$(CONFIG_POSIX_MQUEUE) += mqueue.o msgutil.o $(obj_mq-y)
diff --git a/ipc/ipc_sysctl.c b/ipc/ipc_sysctl.c
index 998d31b..cc34646 100644
--- a/ipc/ipc_sysctl.c
+++ b/ipc/ipc_sysctl.c
@@ -62,29 +62,6 @@ static int proc_ipc_dointvec_minmax_orphans(ctl_table *table, int write,
 	return err;
 }
 
-static int proc_ipc_callback_dointvec_minmax(ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	struct ctl_table ipc_table;
-	size_t lenp_bef = *lenp;
-	int rc;
-
-	memcpy(&ipc_table, table, sizeof(ipc_table));
-	ipc_table.data = get_ipc(table);
-
-	rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
-
-	if (write && !rc && lenp_bef == *lenp)
-		/*
-		 * Tunable has successfully been changed by hand. Disable its
-		 * automatic adjustment. This simply requires unregistering
-		 * the notifiers that trigger recalculation.
-		 */
-		unregister_ipcns_notifier(current->nsproxy->ipc_ns);
-
-	return rc;
-}
-
 static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
 	void __user *buffer, size_t *lenp, loff_t *ppos)
 {
@@ -96,64 +73,11 @@ static int proc_ipc_doulongvec_minmax(ctl_table *table, int write,
 					lenp, ppos);
 }
 
-/*
- * Routine that is called when the file "auto_msgmni" has successfully been
- * written.
- * Two values are allowed:
- * 0: unregister msgmni's callback routine from the ipc namespace notifier
- *    chain. This means that msgmni won't be recomputed anymore upon memory
- *    add/remove or ipc namespace creation/removal.
- * 1: register back the callback routine.
- */
-static void ipc_auto_callback(int val)
-{
-	if (!val)
-		unregister_ipcns_notifier(current->nsproxy->ipc_ns);
-	else {
-		/*
-		 * Re-enable automatic recomputing only if not already
-		 * enabled.
-		 */
-		recompute_msgmni(current->nsproxy->ipc_ns);
-		cond_register_ipcns_notifier(current->nsproxy->ipc_ns);
-	}
-}
-
-static int proc_ipcauto_dointvec_minmax(ctl_table *table, int write,
-	void __user *buffer, size_t *lenp, loff_t *ppos)
-{
-	struct ctl_table ipc_table;
-	size_t lenp_bef = *lenp;
-	int oldval;
-	int rc;
-
-	memcpy(&ipc_table, table, sizeof(ipc_table));
-	ipc_table.data = get_ipc(table);
-	oldval = *((int *)(ipc_table.data));
-
-	rc = proc_dointvec_minmax(&ipc_table, write, buffer, lenp, ppos);
-
-	if (write && !rc && lenp_bef == *lenp) {
-		int newval = *((int *)(ipc_table.data));
-		/*
-		 * The file "auto_msgmni" has correctly been set.
-		 * React by (un)registering the corresponding tunable, if the
-		 * value has changed.
-		 */
-		if (newval != oldval)
-			ipc_auto_callback(newval);
-	}
-
-	return rc;
-}
-
 #else
 #define proc_ipc_doulongvec_minmax NULL
 #define proc_ipc_dointvec	   NULL
 #define proc_ipc_dointvec_minmax   NULL
 #define proc_ipc_dointvec_minmax_orphans   NULL
-#define proc_ipc_callback_dointvec_minmax  NULL
-#define proc_ipcauto_dointvec_minmax NULL
 #endif
 
 static int zero;
@@ -205,7 +129,7 @@ static struct ctl_table ipc_kern_table[] = {
 		.data		= &init_ipc_ns.msg_ctlmni,
 		.maxlen		= sizeof(init_ipc_ns.msg_ctlmni),
 		.mode		= 0644,
-		.proc_handler	= proc_ipc_callback_dointvec_minmax,
+		.proc_handler	= proc_ipc_dointvec_minmax,
 		.extra1		= &zero,
 		.extra2		= &int_max,
 	},
@@ -225,15 +149,6 @@ static struct ctl_table ipc_kern_table[] = {
 		.mode		= 0644,
 		.proc_handler	= proc_ipc_dointvec,
 	},
-	{
-		.procname	= "auto_msgmni",
-		.data		= &init_ipc_ns.auto_msgmni,
-		.maxlen		= sizeof(int),
-		.mode		= 0644,
-		.proc_handler	= proc_ipcauto_dointvec_minmax,
-		.extra1		= &zero,
-		.extra2		= &one,
-	},
 #ifdef CONFIG_CHECKPOINT_RESTORE
 	{
 		.procname	= "sem_next_id",
diff --git a/ipc/ipcns_notifier.c b/ipc/ipcns_notifier.c
deleted file mode 100644
index b9b31a4..0000000
--- a/ipc/ipcns_notifier.c
+++ /dev/null
@@ -1,92 +0,0 @@
-/*
- * linux/ipc/ipcns_notifier.c
- * Copyright (C) 2007 BULL SA. Nadia Derbey
- *
- * Notification mechanism for ipc namespaces:
- * The callback routine registered in the memory chain invokes the ipcns
- * notifier chain with the IPCNS_MEMCHANGED event.
- * Each callback routine registered in the ipcns namespace recomputes msgmni
- * for the owning namespace.
- */
-
-#include <linux/msg.h>
-#include <linux/rcupdate.h>
-#include <linux/notifier.h>
-#include <linux/nsproxy.h>
-#include <linux/ipc_namespace.h>
-
-#include "util.h"
-
-
-
-static BLOCKING_NOTIFIER_HEAD(ipcns_chain);
-
-
-static int ipcns_callback(struct notifier_block *self,
-				unsigned long action, void *arg)
-{
-	struct ipc_namespace *ns;
-
-	switch (action) {
-	case IPCNS_MEMCHANGED:   /* amount of lowmem has changed */
-	case IPCNS_CREATED:
-	case IPCNS_REMOVED:
-		/*
-		 * It's time to recompute msgmni
-		 */
-		ns = container_of(self, struct ipc_namespace, ipcns_nb);
-		/*
-		 * No need to get a reference on the ns: the 1st job of
-		 * free_ipc_ns() is to unregister the callback routine.
-		 * blocking_notifier_chain_unregister takes the wr lock to do
-		 * it.
-		 * When this callback routine is called the rd lock is held by
-		 * blocking_notifier_call_chain.
-		 * So the ipc ns cannot be freed while we are here.
-		 */
-		recompute_msgmni(ns);
-		break;
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-int register_ipcns_notifier(struct ipc_namespace *ns)
-{
-	int rc;
-
-	memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb));
-	ns->ipcns_nb.notifier_call = ipcns_callback;
-	ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI;
-	rc = blocking_notifier_chain_register(&ipcns_chain, &ns->ipcns_nb);
-	if (!rc)
-		ns->auto_msgmni = 1;
-	return rc;
-}
-
-int cond_register_ipcns_notifier(struct ipc_namespace *ns)
-{
-	int rc;
-
-	memset(&ns->ipcns_nb, 0, sizeof(ns->ipcns_nb));
-	ns->ipcns_nb.notifier_call = ipcns_callback;
-	ns->ipcns_nb.priority = IPCNS_CALLBACK_PRI;
-	rc = blocking_notifier_chain_cond_register(&ipcns_chain,
-							&ns->ipcns_nb);
-	if (!rc)
-		ns->auto_msgmni = 1;
-	return rc;
-}
-
-void unregister_ipcns_notifier(struct ipc_namespace *ns)
-{
-	blocking_notifier_chain_unregister(&ipcns_chain, &ns->ipcns_nb);
-	ns->auto_msgmni = 0;
-}
-
-int ipcns_notify(unsigned long val)
-{
-	return blocking_notifier_call_chain(&ipcns_chain, val, NULL);
-}
diff --git a/ipc/msg.c b/ipc/msg.c
index 6498531..ea7e0d1 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -76,43 +76,12 @@ static int newque(struct ipc_namespace *, struct ipc_params *);
 static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif
 
-/*
- * Scale msgmni with the available lowmem size: the memory dedicated to msg
- * queues should occupy at most 1/MSG_MEM_SCALE of lowmem.
- * Also take into account the number of nsproxies created so far.
- * This should be done staying within the (MSGMNI , IPCMNI/nr_ipc_ns) range.
- */
-void recompute_msgmni(struct ipc_namespace *ns)
-{
-	struct sysinfo i;
-	unsigned long allowed;
-	int nb_ns;
-
-	si_meminfo(&i);
-	allowed = (((i.totalram - i.totalhigh) / MSG_MEM_SCALE) * i.mem_unit)
-		/ MSGMNB;
-	nb_ns = atomic_read(&nr_ipc_ns);
-	allowed /= nb_ns;
-
-	if (allowed < MSGMNI) {
-		ns->msg_ctlmni = MSGMNI;
-		return;
-	}
-
-	if (allowed > IPCMNI / nb_ns) {
-		ns->msg_ctlmni = IPCMNI / nb_ns;
-		return;
-	}
-
-	ns->msg_ctlmni = allowed;
-}
 
 void msg_init_ns(struct ipc_namespace *ns)
 {
 	ns->msg_ctlmax = MSGMAX;
 	ns->msg_ctlmnb = MSGMNB;
-
-	recompute_msgmni(ns);
+	ns->msg_ctlmni = MSGMNI;
 
 	atomic_set(&ns->msg_bytes, 0);
 	atomic_set(&ns->msg_hdrs, 0);
@@ -131,9 +100,6 @@ void __init msg_init(void)
 {
 	msg_init_ns(&init_ipc_ns);
 
-	printk(KERN_INFO "msgmni has been set to %d\n",
-		init_ipc_ns.msg_ctlmni);
-
 	ipc_init_proc_interface("sysvipc/msg",
 				"       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
 				IPC_MSG_IDS, sysvipc_msg_proc_show);
diff --git a/ipc/namespace.c b/ipc/namespace.c
index 59451c1..6c01c2a 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -45,14 +45,6 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
 	msg_init_ns(ns);
 	shm_init_ns(ns);
 
-	/*
-	 * msgmni has already been computed for the new ipc ns.
-	 * Thus, do the ipcns creation notification before registering that
-	 * new ipcns in the chain.
-	 */
-	ipcns_notify(IPCNS_CREATED);
-	register_ipcns_notifier(ns);
-
 	ns->user_ns = get_user_ns(user_ns);
 
 	return ns;
@@ -99,25 +91,11 @@ void free_ipcs(struct ipc_namespace *ns, struct ipc_ids *ids,
 
 static void free_ipc_ns(struct ipc_namespace *ns)
 {
-	/*
-	 * Unregistering the hotplug notifier at the beginning guarantees
-	 * that the ipc namespace won't be freed while we are inside the
-	 * callback routine. Since the blocking_notifier_chain_XXX routines
-	 * hold a rw lock on the notifier list, unregister_ipcns_notifier()
-	 * won't take the rw lock before blocking_notifier_call_chain() has
-	 * released the rd lock.
-	 */
-	unregister_ipcns_notifier(ns);
 	sem_exit_ns(ns);
 	msg_exit_ns(ns);
 	shm_exit_ns(ns);
 	atomic_dec(&nr_ipc_ns);
 
-	/*
-	 * Do the ipcns removal notification after decrementing nr_ipc_ns in
-	 * order to have a correct value when recomputing msgmni.
-	 */
-	ipcns_notify(IPCNS_REMOVED);
 	put_user_ns(ns->user_ns);
 	proc_free_inum(ns->proc_inum);
 	kfree(ns);
diff --git a/ipc/util.c b/ipc/util.c
index 2eb0d1e..768e1fc75 100644
--- a/ipc/util.c
+++ b/ipc/util.c
@@ -71,44 +71,6 @@ struct ipc_proc_iface {
 	int (*show)(struct seq_file *, void *);
 };
 
-static void ipc_memory_notifier(struct work_struct *work)
-{
-	ipcns_notify(IPCNS_MEMCHANGED);
-}
-
-static int ipc_memory_callback(struct notifier_block *self,
-				unsigned long action, void *arg)
-{
-	static DECLARE_WORK(ipc_memory_wq, ipc_memory_notifier);
-
-	switch (action) {
-	case MEM_ONLINE:    /* memory successfully brought online */
-	case MEM_OFFLINE:   /* or offline: it's time to recompute msgmni */
-		/*
-		 * This is done by invoking the ipcns notifier chain with the
-		 * IPC_MEMCHANGED event.
-		 * In order not to keep the lock on the hotplug memory chain
-		 * for too long, queue a work item that will, when waken up,
-		 * activate the ipcns notification chain.
-		 */
-		schedule_work(&ipc_memory_wq);
-		break;
-	case MEM_GOING_ONLINE:
-	case MEM_GOING_OFFLINE:
-	case MEM_CANCEL_ONLINE:
-	case MEM_CANCEL_OFFLINE:
-	default:
-		break;
-	}
-
-	return NOTIFY_OK;
-}
-
-static struct notifier_block ipc_memory_nb = {
-	.notifier_call = ipc_memory_callback,
-	.priority = IPC_CALLBACK_PRI,
-};
-
 /**
  * ipc_init - initialise ipc subsystem
  *
@@ -124,8 +86,6 @@ static int __init ipc_init(void)
 	sem_init();
 	msg_init();
 	shm_init();
-	register_hotmemory_notifier(&ipc_memory_nb);
-	register_ipcns_notifier(&init_ipc_ns);
 	return 0;
 }
 device_initcall(ipc_init);
-- 
1.9.3

[PATCH 2/3] ipc/sem.c: increase SEMMSL, SEMMNI, SEMOPM

[Manfred Spraul]

SysV can be abused to allocated locked kernel memory.
For most systems, a small limit doesn't make sense,
see the discussion with regards to SHMMAX.

Therefore: Increase the sysv sem limits to the maximum supported.

With regards to the maximum supported:
Some of the specified hard limits are not correct anymore.

Therefore here is an updated list:

- SEMMNI must stay below IPCMNI, which is 32768.
  As for SHMMAX: Stay a bit below this limit.

- SEMMSL was limited to 8k, to ensure that the kmalloc for the
  kernel array was limited to 16 kB (order=2)

  This doesn't apply anymore:
   - the allocation size isn't sizeof(short)*nsems anymore.
   - ipc_alloc falls back to vmalloc

- SEMOPM should stay below 1000, to limit the kmalloc in
  semtimedop() to an order=1 allocation.

  This might be a real issue: The Redhat documentation
  shows an example with SEMOPM=5010:

https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Tuning_and_Optimizing_Red_Hat_Enterprise_Linux_for_Oracle_9i_and_10g_Databases/sect-Oracle_9i_and_10g_Tuning_Guide-Setting_Semaphores-An_Example_of_Semaphore_Settings.html

  If Oracle really uses operations with SEMOPM 5000 and larger, then
  semtimedop() should be converted from kmalloc to ipc_alloc.

Note:
If an administrator must limit the memory allocations, then
he can set MSGMNI as necessary.

Or he can disable sysv entirely (as e.g. done with Android).
---
 include/uapi/linux/sem.h | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/include/uapi/linux/sem.h b/include/uapi/linux/sem.h
index 541fce0..a4f47d9 100644
--- a/include/uapi/linux/sem.h
+++ b/include/uapi/linux/sem.h
@@ -63,10 +63,10 @@ struct  seminfo {
 	int semaem;
 };
 
-#define SEMMNI  128             /* <= IPCMNI  max # of semaphore identifiers */
-#define SEMMSL  250             /* <= 8 000 max num of semaphores per id */
+#define SEMMNI  32000           /* <= IPCMNI  max # of semaphore identifiers */
+#define SEMMSL  32000           /* <= INT_MAX max num of semaphores per id */
 #define SEMMNS  (SEMMNI*SEMMSL) /* <= INT_MAX max # of semaphores in system */
-#define SEMOPM  32	        /* <= 1 000 max num of ops per semop call */
+#define SEMOPM  1000	        /* <= 1 000 max num of ops per semop call */
 #define SEMVMX  32767           /* <= 32767 semaphore maximum value */
 #define SEMAEM  SEMVMX          /* adjust on exit max value */
 
-- 
1.9.3

[PATCH 3/3] ipc namespace: copy settings from parent namespace

[Manfred Spraul]

Right now, each IPC namespace starts with the kernel boot standard
settings.
This patch changes that:
Now each new namespace starts with the settings from the parent
namespace.

The patch updates
- SysV msg
- SysV sem
- SysV shm
- POSIX mqueues

It's just a proposal - only partially tested

--
	Manfred
---
 include/linux/ipc_namespace.h |  6 ++++--
 ipc/mqueue.c                  | 23 ++++++++++++++++-------
 ipc/msg.c                     | 16 +++++++++++-----
 ipc/namespace.c               |  6 +++---
 ipc/sem.c                     | 19 +++++++++++++------
 ipc/shm.c                     | 19 +++++++++++++------
 ipc/util.h                    | 20 ++++++++++++++------
 7 files changed, 74 insertions(+), 35 deletions(-)

diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
index e365d5e..1cc36a0 100644
--- a/include/linux/ipc_namespace.h
+++ b/include/linux/ipc_namespace.h
@@ -73,7 +73,7 @@ static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
 #endif /* CONFIG_SYSVIPC */
 
 #ifdef CONFIG_POSIX_MQUEUE
-extern int mq_init_ns(struct ipc_namespace *ns);
+extern int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
 /*
  * POSIX Message Queue default values:
  *
@@ -108,7 +108,9 @@ extern int mq_init_ns(struct ipc_namespace *ns);
 #define DFLT_MSGSIZEMAX		     8192
 #define HARD_MSGSIZEMAX	    (16*1024*1024)
 #else
-static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
+static inline int mq_init_ns(struct ipc_namespace *ns,
+				struct ipc_namespace *old_ns)
+{ return 0; }
 #endif
 
 #if defined(CONFIG_IPC_NS)
diff --git a/ipc/mqueue.c b/ipc/mqueue.c
index 4fcf39a..3473072d 100644
--- a/ipc/mqueue.c
+++ b/ipc/mqueue.c
@@ -1397,14 +1397,23 @@ static struct file_system_type mqueue_fs_type = {
 	.fs_flags = FS_USERNS_MOUNT,
 };
 
-int mq_init_ns(struct ipc_namespace *ns)
+int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
 {
+	if (old_ns != NULL) {
+		ns->mq_queues_max    = old_ns->mq_queues_max;
+		ns->mq_msg_max       = old_ns->mq_msg_max;
+		ns->mq_msgsize_max   = old_ns->mq_msgsize_max;
+		ns->mq_msg_default   = old_ns->mq_msg_default;
+		ns->mq_msgsize_default  = old_ns->mq_msgsize_default;
+	} else {
+		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_queues_count  = 0;
-	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)) {
@@ -1444,7 +1453,7 @@ static int __init init_mqueue_fs(void)
 
 	spin_lock_init(&mq_lock);
 
-	error = mq_init_ns(&init_ipc_ns);
+	error = mq_init_ns(&init_ipc_ns, NULL);
 	if (error)
 		goto out_filesystem;
 
diff --git a/ipc/msg.c b/ipc/msg.c
index ea7e0d1..d457052 100644
--- a/ipc/msg.c
+++ b/ipc/msg.c
@@ -77,11 +77,17 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
 #endif
 
 
-void msg_init_ns(struct ipc_namespace *ns)
+void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
 {
-	ns->msg_ctlmax = MSGMAX;
-	ns->msg_ctlmnb = MSGMNB;
-	ns->msg_ctlmni = MSGMNI;
+	if (old_ns != NULL) {
+		ns->msg_ctlmax = old_ns->msg_ctlmax;
+		ns->msg_ctlmnb = old_ns->msg_ctlmnb;
+		ns->msg_ctlmni = old_ns->msg_ctlmni;
+	} else {
+		ns->msg_ctlmax = MSGMAX;
+		ns->msg_ctlmnb = MSGMNB;
+		ns->msg_ctlmni = MSGMNI;
+	}
 
 	atomic_set(&ns->msg_bytes, 0);
 	atomic_set(&ns->msg_hdrs, 0);
@@ -98,7 +104,7 @@ void msg_exit_ns(struct ipc_namespace *ns)
 
 void __init msg_init(void)
 {
-	msg_init_ns(&init_ipc_ns);
+	msg_init_ns(&init_ipc_ns, NULL);
 
 	ipc_init_proc_interface("sysvipc/msg",
 				"       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
diff --git a/ipc/namespace.c b/ipc/namespace.c
index 6c01c2a..33ee4be 100644
--- a/ipc/namespace.c
+++ b/ipc/namespace.c
@@ -41,9 +41,9 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
 	}
 	atomic_inc(&nr_ipc_ns);
 
-	sem_init_ns(ns);
-	msg_init_ns(ns);
-	shm_init_ns(ns);
+	sem_init_ns(ns, old_ns);
+	msg_init_ns(ns, old_ns);
+	shm_init_ns(ns, old_ns);
 
 	ns->user_ns = get_user_ns(user_ns);
 
diff --git a/ipc/sem.c b/ipc/sem.c
index bee5554..0e232e6 100644
--- a/ipc/sem.c
+++ b/ipc/sem.c
@@ -170,12 +170,19 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
 #define sc_semopm	sem_ctls[2]
 #define sc_semmni	sem_ctls[3]
 
-void sem_init_ns(struct ipc_namespace *ns)
+void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
 {
-	ns->sc_semmsl = SEMMSL;
-	ns->sc_semmns = SEMMNS;
-	ns->sc_semopm = SEMOPM;
-	ns->sc_semmni = SEMMNI;
+	if (old_ns != NULL) {
+		ns->sc_semmsl = old_ns->sc_semmsl;
+		ns->sc_semmns = old_ns->sc_semmns;
+		ns->sc_semopm = old_ns->sc_semopm;
+		ns->sc_semmni = old_ns->sc_semmni;
+	} else {
+		ns->sc_semmsl = SEMMSL;
+		ns->sc_semmns = SEMMNS;
+		ns->sc_semopm = SEMOPM;
+		ns->sc_semmni = SEMMNI;
+	}
 	ns->used_sems = 0;
 	ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
 }
@@ -190,7 +197,7 @@ void sem_exit_ns(struct ipc_namespace *ns)
 
 void __init sem_init(void)
 {
-	sem_init_ns(&init_ipc_ns);
+	sem_init_ns(&init_ipc_ns, NULL);
 	ipc_init_proc_interface("sysvipc/sem",
 				"       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
 				IPC_SEM_IDS, sysvipc_sem_proc_show);
diff --git a/ipc/shm.c b/ipc/shm.c
index 7645961..5c54b25 100644
--- a/ipc/shm.c
+++ b/ipc/shm.c
@@ -72,12 +72,19 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
 static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
 #endif
 
-void shm_init_ns(struct ipc_namespace *ns)
+void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
 {
-	ns->shm_ctlmax = SHMMAX;
-	ns->shm_ctlall = SHMALL;
-	ns->shm_ctlmni = SHMMNI;
-	ns->shm_rmid_forced = 0;
+	if (old_ns != NULL) {
+		ns->shm_ctlmax = old_ns->shm_ctlmax;
+		ns->shm_ctlall = old_ns->shm_ctlall;
+		ns->shm_ctlmni = old_ns->shm_ctlmni;
+		ns->shm_rmid_forced = old_ns->shm_rmid_forced;
+	} else {
+		ns->shm_ctlmax = SHMMAX;
+		ns->shm_ctlall = SHMALL;
+		ns->shm_ctlmni = SHMMNI;
+		ns->shm_rmid_forced = 0;
+	}
 	ns->shm_tot = 0;
 	ipc_init_ids(&shm_ids(ns));
 }
@@ -110,7 +117,7 @@ void shm_exit_ns(struct ipc_namespace *ns)
 
 static int __init ipc_ns_init(void)
 {
-	shm_init_ns(&init_ipc_ns);
+	shm_init_ns(&init_ipc_ns, NULL);
 	return 0;
 }
 
diff --git a/ipc/util.h b/ipc/util.h
index 9c47d6f..a66d8f2 100644
--- a/ipc/util.h
+++ b/ipc/util.h
@@ -30,17 +30,25 @@ static inline void mq_put_mnt(struct ipc_namespace *ns) { }
 #endif
 
 #ifdef CONFIG_SYSVIPC
-void sem_init_ns(struct ipc_namespace *ns);
-void msg_init_ns(struct ipc_namespace *ns);
-void shm_init_ns(struct ipc_namespace *ns);
+void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
+void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
+void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
 
 void sem_exit_ns(struct ipc_namespace *ns);
 void msg_exit_ns(struct ipc_namespace *ns);
 void shm_exit_ns(struct ipc_namespace *ns);
 #else
-static inline void sem_init_ns(struct ipc_namespace *ns) { }
-static inline void msg_init_ns(struct ipc_namespace *ns) { }
-static inline void shm_init_ns(struct ipc_namespace *ns) { }
+static inline void sem_init_ns(struct ipc_namespace *ns,
+				struct ipc_namespace *old_ns)
+{ }
+
+static inline void msg_init_ns(struct ipc_namespace *ns,
+				struct ipc_namespace *old_ns)
+{ }
+
+static inline void shm_init_ns(struct ipc_namespace *ns,
+				struct ipc_namespace *old_ns)
+{ }
 
 static inline void sem_exit_ns(struct ipc_namespace *ns) { }
 static inline void msg_exit_ns(struct ipc_namespace *ns) { }
-- 
1.9.3

Re: [PATCH 3/3] ipc namespace: copy settings from parent namespace

[Michael Kerrisk (man-pages)]

[CC += Eric and containers@]

Hi Manfred,

On Thu, May 29, 2014 at 8:46 PM, Manfred Spraul
<manfred@colorfullife.com> wrote:
> Right now, each IPC namespace starts with the kernel boot standard
> settings.
> This patch changes that:
> Now each new namespace starts with the settings from the parent
> namespace.
>
> The patch updates
> - SysV msg
> - SysV sem
> - SysV shm
> - POSIX mqueues
>
> It's just a proposal - only partially tested

This seems like a sane idea, but maybe the containers folk and Eric
have some comments.

Cheers,

Michael


> --
>         Manfred
> ---
>  include/linux/ipc_namespace.h |  6 ++++--
>  ipc/mqueue.c                  | 23 ++++++++++++++++-------
>  ipc/msg.c                     | 16 +++++++++++-----
>  ipc/namespace.c               |  6 +++---
>  ipc/sem.c                     | 19 +++++++++++++------
>  ipc/shm.c                     | 19 +++++++++++++------
>  ipc/util.h                    | 20 ++++++++++++++------
>  7 files changed, 74 insertions(+), 35 deletions(-)
>
> diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> index e365d5e..1cc36a0 100644
> --- a/include/linux/ipc_namespace.h
> +++ b/include/linux/ipc_namespace.h
> @@ -73,7 +73,7 @@ static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
>  #endif /* CONFIG_SYSVIPC */
>
>  #ifdef CONFIG_POSIX_MQUEUE
> -extern int mq_init_ns(struct ipc_namespace *ns);
> +extern int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
>  /*
>   * POSIX Message Queue default values:
>   *
> @@ -108,7 +108,9 @@ extern int mq_init_ns(struct ipc_namespace *ns);
>  #define DFLT_MSGSIZEMAX                     8192
>  #define HARD_MSGSIZEMAX            (16*1024*1024)
>  #else
> -static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
> +static inline int mq_init_ns(struct ipc_namespace *ns,
> +                               struct ipc_namespace *old_ns)
> +{ return 0; }
>  #endif
>
>  #if defined(CONFIG_IPC_NS)
> diff --git a/ipc/mqueue.c b/ipc/mqueue.c
> index 4fcf39a..3473072d 100644
> --- a/ipc/mqueue.c
> +++ b/ipc/mqueue.c
> @@ -1397,14 +1397,23 @@ static struct file_system_type mqueue_fs_type = {
>         .fs_flags = FS_USERNS_MOUNT,
>  };
>
> -int mq_init_ns(struct ipc_namespace *ns)
> +int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
>  {
> +       if (old_ns != NULL) {
> +               ns->mq_queues_max    = old_ns->mq_queues_max;
> +               ns->mq_msg_max       = old_ns->mq_msg_max;
> +               ns->mq_msgsize_max   = old_ns->mq_msgsize_max;
> +               ns->mq_msg_default   = old_ns->mq_msg_default;
> +               ns->mq_msgsize_default  = old_ns->mq_msgsize_default;
> +       } else {
> +               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_queues_count  = 0;
> -       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)) {
> @@ -1444,7 +1453,7 @@ static int __init init_mqueue_fs(void)
>
>         spin_lock_init(&mq_lock);
>
> -       error = mq_init_ns(&init_ipc_ns);
> +       error = mq_init_ns(&init_ipc_ns, NULL);
>         if (error)
>                 goto out_filesystem;
>
> diff --git a/ipc/msg.c b/ipc/msg.c
> index ea7e0d1..d457052 100644
> --- a/ipc/msg.c
> +++ b/ipc/msg.c
> @@ -77,11 +77,17 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
>  #endif
>
>
> -void msg_init_ns(struct ipc_namespace *ns)
> +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
>  {
> -       ns->msg_ctlmax = MSGMAX;
> -       ns->msg_ctlmnb = MSGMNB;
> -       ns->msg_ctlmni = MSGMNI;
> +       if (old_ns != NULL) {
> +               ns->msg_ctlmax = old_ns->msg_ctlmax;
> +               ns->msg_ctlmnb = old_ns->msg_ctlmnb;
> +               ns->msg_ctlmni = old_ns->msg_ctlmni;
> +       } else {
> +               ns->msg_ctlmax = MSGMAX;
> +               ns->msg_ctlmnb = MSGMNB;
> +               ns->msg_ctlmni = MSGMNI;
> +       }
>
>         atomic_set(&ns->msg_bytes, 0);
>         atomic_set(&ns->msg_hdrs, 0);
> @@ -98,7 +104,7 @@ void msg_exit_ns(struct ipc_namespace *ns)
>
>  void __init msg_init(void)
>  {
> -       msg_init_ns(&init_ipc_ns);
> +       msg_init_ns(&init_ipc_ns, NULL);
>
>         ipc_init_proc_interface("sysvipc/msg",
>                                 "       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
> diff --git a/ipc/namespace.c b/ipc/namespace.c
> index 6c01c2a..33ee4be 100644
> --- a/ipc/namespace.c
> +++ b/ipc/namespace.c
> @@ -41,9 +41,9 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
>         }
>         atomic_inc(&nr_ipc_ns);
>
> -       sem_init_ns(ns);
> -       msg_init_ns(ns);
> -       shm_init_ns(ns);
> +       sem_init_ns(ns, old_ns);
> +       msg_init_ns(ns, old_ns);
> +       shm_init_ns(ns, old_ns);
>
>         ns->user_ns = get_user_ns(user_ns);
>
> diff --git a/ipc/sem.c b/ipc/sem.c
> index bee5554..0e232e6 100644
> --- a/ipc/sem.c
> +++ b/ipc/sem.c
> @@ -170,12 +170,19 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
>  #define sc_semopm      sem_ctls[2]
>  #define sc_semmni      sem_ctls[3]
>
> -void sem_init_ns(struct ipc_namespace *ns)
> +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
>  {
> -       ns->sc_semmsl = SEMMSL;
> -       ns->sc_semmns = SEMMNS;
> -       ns->sc_semopm = SEMOPM;
> -       ns->sc_semmni = SEMMNI;
> +       if (old_ns != NULL) {
> +               ns->sc_semmsl = old_ns->sc_semmsl;
> +               ns->sc_semmns = old_ns->sc_semmns;
> +               ns->sc_semopm = old_ns->sc_semopm;
> +               ns->sc_semmni = old_ns->sc_semmni;
> +       } else {
> +               ns->sc_semmsl = SEMMSL;
> +               ns->sc_semmns = SEMMNS;
> +               ns->sc_semopm = SEMOPM;
> +               ns->sc_semmni = SEMMNI;
> +       }
>         ns->used_sems = 0;
>         ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
>  }
> @@ -190,7 +197,7 @@ void sem_exit_ns(struct ipc_namespace *ns)
>
>  void __init sem_init(void)
>  {
> -       sem_init_ns(&init_ipc_ns);
> +       sem_init_ns(&init_ipc_ns, NULL);
>         ipc_init_proc_interface("sysvipc/sem",
>                                 "       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
>                                 IPC_SEM_IDS, sysvipc_sem_proc_show);
> diff --git a/ipc/shm.c b/ipc/shm.c
> index 7645961..5c54b25 100644
> --- a/ipc/shm.c
> +++ b/ipc/shm.c
> @@ -72,12 +72,19 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
>  static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
>  #endif
>
> -void shm_init_ns(struct ipc_namespace *ns)
> +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
>  {
> -       ns->shm_ctlmax = SHMMAX;
> -       ns->shm_ctlall = SHMALL;
> -       ns->shm_ctlmni = SHMMNI;
> -       ns->shm_rmid_forced = 0;
> +       if (old_ns != NULL) {
> +               ns->shm_ctlmax = old_ns->shm_ctlmax;
> +               ns->shm_ctlall = old_ns->shm_ctlall;
> +               ns->shm_ctlmni = old_ns->shm_ctlmni;
> +               ns->shm_rmid_forced = old_ns->shm_rmid_forced;
> +       } else {
> +               ns->shm_ctlmax = SHMMAX;
> +               ns->shm_ctlall = SHMALL;
> +               ns->shm_ctlmni = SHMMNI;
> +               ns->shm_rmid_forced = 0;
> +       }
>         ns->shm_tot = 0;
>         ipc_init_ids(&shm_ids(ns));
>  }
> @@ -110,7 +117,7 @@ void shm_exit_ns(struct ipc_namespace *ns)
>
>  static int __init ipc_ns_init(void)
>  {
> -       shm_init_ns(&init_ipc_ns);
> +       shm_init_ns(&init_ipc_ns, NULL);
>         return 0;
>  }
>
> diff --git a/ipc/util.h b/ipc/util.h
> index 9c47d6f..a66d8f2 100644
> --- a/ipc/util.h
> +++ b/ipc/util.h
> @@ -30,17 +30,25 @@ static inline void mq_put_mnt(struct ipc_namespace *ns) { }
>  #endif
>
>  #ifdef CONFIG_SYSVIPC
> -void sem_init_ns(struct ipc_namespace *ns);
> -void msg_init_ns(struct ipc_namespace *ns);
> -void shm_init_ns(struct ipc_namespace *ns);
> +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
>
>  void sem_exit_ns(struct ipc_namespace *ns);
>  void msg_exit_ns(struct ipc_namespace *ns);
>  void shm_exit_ns(struct ipc_namespace *ns);
>  #else
> -static inline void sem_init_ns(struct ipc_namespace *ns) { }
> -static inline void msg_init_ns(struct ipc_namespace *ns) { }
> -static inline void shm_init_ns(struct ipc_namespace *ns) { }
> +static inline void sem_init_ns(struct ipc_namespace *ns,
> +                               struct ipc_namespace *old_ns)
> +{ }
> +
> +static inline void msg_init_ns(struct ipc_namespace *ns,
> +                               struct ipc_namespace *old_ns)
> +{ }
> +
> +static inline void shm_init_ns(struct ipc_namespace *ns,
> +                               struct ipc_namespace *old_ns)
> +{ }
>
>  static inline void sem_exit_ns(struct ipc_namespace *ns) { }
>  static inline void msg_exit_ns(struct ipc_namespace *ns) { }
> --
> 1.9.3
>



-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

Re: [PATCH 3/3] ipc namespace: copy settings from parent namespace

[Serge E. Hallyn]

Quoting Michael Kerrisk (man-pages) (mtk.manpages@gmail.com):
> [CC += Eric and containers@]
> 
> Hi Manfred,
> 
> On Thu, May 29, 2014 at 8:46 PM, Manfred Spraul
> <manfred@colorfullife.com> wrote:
> > Right now, each IPC namespace starts with the kernel boot standard
> > settings.
> > This patch changes that:
> > Now each new namespace starts with the settings from the parent
> > namespace.
> >
> > The patch updates
> > - SysV msg
> > - SysV sem
> > - SysV shm
> > - POSIX mqueues
> >
> > It's just a proposal - only partially tested
> 
> This seems like a sane idea, but maybe the containers folk and Eric
> have some comments.

Looks good to me.

> Cheers,
> 
> Michael
> 
> 
> > --
> >         Manfred
> > ---
> >  include/linux/ipc_namespace.h |  6 ++++--
> >  ipc/mqueue.c                  | 23 ++++++++++++++++-------
> >  ipc/msg.c                     | 16 +++++++++++-----
> >  ipc/namespace.c               |  6 +++---
> >  ipc/sem.c                     | 19 +++++++++++++------
> >  ipc/shm.c                     | 19 +++++++++++++------
> >  ipc/util.h                    | 20 ++++++++++++++------
> >  7 files changed, 74 insertions(+), 35 deletions(-)
> >
> > diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h
> > index e365d5e..1cc36a0 100644
> > --- a/include/linux/ipc_namespace.h
> > +++ b/include/linux/ipc_namespace.h
> > @@ -73,7 +73,7 @@ static inline void shm_destroy_orphaned(struct ipc_namespace *ns) {}
> >  #endif /* CONFIG_SYSVIPC */
> >
> >  #ifdef CONFIG_POSIX_MQUEUE
> > -extern int mq_init_ns(struct ipc_namespace *ns);
> > +extern int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> >  /*
> >   * POSIX Message Queue default values:
> >   *
> > @@ -108,7 +108,9 @@ extern int mq_init_ns(struct ipc_namespace *ns);
> >  #define DFLT_MSGSIZEMAX                     8192
> >  #define HARD_MSGSIZEMAX            (16*1024*1024)
> >  #else
> > -static inline int mq_init_ns(struct ipc_namespace *ns) { return 0; }
> > +static inline int mq_init_ns(struct ipc_namespace *ns,
> > +                               struct ipc_namespace *old_ns)
> > +{ return 0; }
> >  #endif
> >
> >  #if defined(CONFIG_IPC_NS)
> > diff --git a/ipc/mqueue.c b/ipc/mqueue.c
> > index 4fcf39a..3473072d 100644
> > --- a/ipc/mqueue.c
> > +++ b/ipc/mqueue.c
> > @@ -1397,14 +1397,23 @@ static struct file_system_type mqueue_fs_type = {
> >         .fs_flags = FS_USERNS_MOUNT,
> >  };
> >
> > -int mq_init_ns(struct ipc_namespace *ns)
> > +int mq_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> >  {
> > +       if (old_ns != NULL) {
> > +               ns->mq_queues_max    = old_ns->mq_queues_max;
> > +               ns->mq_msg_max       = old_ns->mq_msg_max;
> > +               ns->mq_msgsize_max   = old_ns->mq_msgsize_max;
> > +               ns->mq_msg_default   = old_ns->mq_msg_default;
> > +               ns->mq_msgsize_default  = old_ns->mq_msgsize_default;
> > +       } else {
> > +               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_queues_count  = 0;
> > -       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)) {
> > @@ -1444,7 +1453,7 @@ static int __init init_mqueue_fs(void)
> >
> >         spin_lock_init(&mq_lock);
> >
> > -       error = mq_init_ns(&init_ipc_ns);
> > +       error = mq_init_ns(&init_ipc_ns, NULL);
> >         if (error)
> >                 goto out_filesystem;
> >
> > diff --git a/ipc/msg.c b/ipc/msg.c
> > index ea7e0d1..d457052 100644
> > --- a/ipc/msg.c
> > +++ b/ipc/msg.c
> > @@ -77,11 +77,17 @@ static int sysvipc_msg_proc_show(struct seq_file *s, void *it);
> >  #endif
> >
> >
> > -void msg_init_ns(struct ipc_namespace *ns)
> > +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> >  {
> > -       ns->msg_ctlmax = MSGMAX;
> > -       ns->msg_ctlmnb = MSGMNB;
> > -       ns->msg_ctlmni = MSGMNI;
> > +       if (old_ns != NULL) {
> > +               ns->msg_ctlmax = old_ns->msg_ctlmax;
> > +               ns->msg_ctlmnb = old_ns->msg_ctlmnb;
> > +               ns->msg_ctlmni = old_ns->msg_ctlmni;
> > +       } else {
> > +               ns->msg_ctlmax = MSGMAX;
> > +               ns->msg_ctlmnb = MSGMNB;
> > +               ns->msg_ctlmni = MSGMNI;
> > +       }
> >
> >         atomic_set(&ns->msg_bytes, 0);
> >         atomic_set(&ns->msg_hdrs, 0);
> > @@ -98,7 +104,7 @@ void msg_exit_ns(struct ipc_namespace *ns)
> >
> >  void __init msg_init(void)
> >  {
> > -       msg_init_ns(&init_ipc_ns);
> > +       msg_init_ns(&init_ipc_ns, NULL);
> >
> >         ipc_init_proc_interface("sysvipc/msg",
> >                                 "       key      msqid perms      cbytes       qnum lspid lrpid   uid   gid  cuid  cgid      stime      rtime      ctime\n",
> > diff --git a/ipc/namespace.c b/ipc/namespace.c
> > index 6c01c2a..33ee4be 100644
> > --- a/ipc/namespace.c
> > +++ b/ipc/namespace.c
> > @@ -41,9 +41,9 @@ static struct ipc_namespace *create_ipc_ns(struct user_namespace *user_ns,
> >         }
> >         atomic_inc(&nr_ipc_ns);
> >
> > -       sem_init_ns(ns);
> > -       msg_init_ns(ns);
> > -       shm_init_ns(ns);
> > +       sem_init_ns(ns, old_ns);
> > +       msg_init_ns(ns, old_ns);
> > +       shm_init_ns(ns, old_ns);
> >
> >         ns->user_ns = get_user_ns(user_ns);
> >
> > diff --git a/ipc/sem.c b/ipc/sem.c
> > index bee5554..0e232e6 100644
> > --- a/ipc/sem.c
> > +++ b/ipc/sem.c
> > @@ -170,12 +170,19 @@ static int sysvipc_sem_proc_show(struct seq_file *s, void *it);
> >  #define sc_semopm      sem_ctls[2]
> >  #define sc_semmni      sem_ctls[3]
> >
> > -void sem_init_ns(struct ipc_namespace *ns)
> > +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> >  {
> > -       ns->sc_semmsl = SEMMSL;
> > -       ns->sc_semmns = SEMMNS;
> > -       ns->sc_semopm = SEMOPM;
> > -       ns->sc_semmni = SEMMNI;
> > +       if (old_ns != NULL) {
> > +               ns->sc_semmsl = old_ns->sc_semmsl;
> > +               ns->sc_semmns = old_ns->sc_semmns;
> > +               ns->sc_semopm = old_ns->sc_semopm;
> > +               ns->sc_semmni = old_ns->sc_semmni;
> > +       } else {
> > +               ns->sc_semmsl = SEMMSL;
> > +               ns->sc_semmns = SEMMNS;
> > +               ns->sc_semopm = SEMOPM;
> > +               ns->sc_semmni = SEMMNI;
> > +       }
> >         ns->used_sems = 0;
> >         ipc_init_ids(&ns->ids[IPC_SEM_IDS]);
> >  }
> > @@ -190,7 +197,7 @@ void sem_exit_ns(struct ipc_namespace *ns)
> >
> >  void __init sem_init(void)
> >  {
> > -       sem_init_ns(&init_ipc_ns);
> > +       sem_init_ns(&init_ipc_ns, NULL);
> >         ipc_init_proc_interface("sysvipc/sem",
> >                                 "       key      semid perms      nsems   uid   gid  cuid  cgid      otime      ctime\n",
> >                                 IPC_SEM_IDS, sysvipc_sem_proc_show);
> > diff --git a/ipc/shm.c b/ipc/shm.c
> > index 7645961..5c54b25 100644
> > --- a/ipc/shm.c
> > +++ b/ipc/shm.c
> > @@ -72,12 +72,19 @@ static void shm_destroy(struct ipc_namespace *ns, struct shmid_kernel *shp);
> >  static int sysvipc_shm_proc_show(struct seq_file *s, void *it);
> >  #endif
> >
> > -void shm_init_ns(struct ipc_namespace *ns)
> > +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns)
> >  {
> > -       ns->shm_ctlmax = SHMMAX;
> > -       ns->shm_ctlall = SHMALL;
> > -       ns->shm_ctlmni = SHMMNI;
> > -       ns->shm_rmid_forced = 0;
> > +       if (old_ns != NULL) {
> > +               ns->shm_ctlmax = old_ns->shm_ctlmax;
> > +               ns->shm_ctlall = old_ns->shm_ctlall;
> > +               ns->shm_ctlmni = old_ns->shm_ctlmni;
> > +               ns->shm_rmid_forced = old_ns->shm_rmid_forced;
> > +       } else {
> > +               ns->shm_ctlmax = SHMMAX;
> > +               ns->shm_ctlall = SHMALL;
> > +               ns->shm_ctlmni = SHMMNI;
> > +               ns->shm_rmid_forced = 0;
> > +       }
> >         ns->shm_tot = 0;
> >         ipc_init_ids(&shm_ids(ns));
> >  }
> > @@ -110,7 +117,7 @@ void shm_exit_ns(struct ipc_namespace *ns)
> >
> >  static int __init ipc_ns_init(void)
> >  {
> > -       shm_init_ns(&init_ipc_ns);
> > +       shm_init_ns(&init_ipc_ns, NULL);
> >         return 0;
> >  }
> >
> > diff --git a/ipc/util.h b/ipc/util.h
> > index 9c47d6f..a66d8f2 100644
> > --- a/ipc/util.h
> > +++ b/ipc/util.h
> > @@ -30,17 +30,25 @@ static inline void mq_put_mnt(struct ipc_namespace *ns) { }
> >  #endif
> >
> >  #ifdef CONFIG_SYSVIPC
> > -void sem_init_ns(struct ipc_namespace *ns);
> > -void msg_init_ns(struct ipc_namespace *ns);
> > -void shm_init_ns(struct ipc_namespace *ns);
> > +void sem_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> > +void msg_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> > +void shm_init_ns(struct ipc_namespace *ns, struct ipc_namespace *old_ns);
> >
> >  void sem_exit_ns(struct ipc_namespace *ns);
> >  void msg_exit_ns(struct ipc_namespace *ns);
> >  void shm_exit_ns(struct ipc_namespace *ns);
> >  #else
> > -static inline void sem_init_ns(struct ipc_namespace *ns) { }
> > -static inline void msg_init_ns(struct ipc_namespace *ns) { }
> > -static inline void shm_init_ns(struct ipc_namespace *ns) { }
> > +static inline void sem_init_ns(struct ipc_namespace *ns,
> > +                               struct ipc_namespace *old_ns)
> > +{ }
> > +
> > +static inline void msg_init_ns(struct ipc_namespace *ns,
> > +                               struct ipc_namespace *old_ns)
> > +{ }
> > +
> > +static inline void shm_init_ns(struct ipc_namespace *ns,
> > +                               struct ipc_namespace *old_ns)
> > +{ }
> >
> >  static inline void sem_exit_ns(struct ipc_namespace *ns) { }
> >  static inline void msg_exit_ns(struct ipc_namespace *ns) { }
> > --
> > 1.9.3
> >
> 
> 
> 
> -- 
> Michael Kerrisk
> Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
> Linux/UNIX System Programming Training: http://man7.org/training/
> _______________________________________________
> Containers mailing list
> Containers@lists.linux-foundation.org
> https://lists.linuxfoundation.org/mailman/listinfo/containers

Re: [PATCH 0/3] ipc: Further updates to sysv/mqueue limits

[Michael Kerrisk (man-pages)]

On 05/29/2014 08:46 PM, Manfred Spraul wrote:
> Hi all,
> 
> a) If we increase SHMMAX/SHMALL, then it makes sense to
>    increase MSGMNI, too.
>    And: This allows to remove the automatic scaling (~300 lines)
> 
> b) We can also increase SEMMSL, SEMMNI and SEMOPM
> 
> c) I think it would make more sense if a namespace starts with the
>    limits from it's parent:
>    If an admin set the limits, then he probably wants that these limits also
>    apply for a new child namespace.

Hi Manfred,

This these patches change the API/ABI, could you CC linux-api [1] for future
iterations.

Cheers,

Michael

[1] https://www.kernel.org/doc/man-pages/linux-api-ml.html


> All patches are RFC - they compile, but that's it.
> 
> TODO:
> - check if the sysv sem limits are sane.
>   Especially the SEMOPM - if real users exist that pass > 1k ops, then
>   switch from kmalloc to vmalloc.
> 
>   @the Redhat developers: Do you have any idea where this "often
>   recommended" comes from?
>   https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Tuning_and_Optimizing_Red_Hat_Enterprise_Linux_for_Oracle_9i_and_10g_Databases/sect-Oracle_9i_and_10g_Tuning_Guide-Setting_Semaphores-The_SEMOPM_Parameter.html
> 
> - copy Davidlohrs explanation for the sysv shm limits to sysv msg and
>   sysv sem.
> 
> - check if we should also increase the limits for posix mqueue
> 
> - decide if it would make sense to increase IPCMNI:
> 
>   Right now, it is 32768. This means that after 65536 pairs of
>   semget()/semctl(IPC_RMID), semget() will return the same identifier
>   again - and a semop(old_id) won't return -EINVAL, instead it will
>   access the "new" array, which is probably now what the caller
>   intended to do.
> 
>   The split is arbitrary - we could also split it 1048576/2048 or any
>   other split we want.
> 
> - test everything.
> 
> --
> 	Manfred
> 


-- 
Michael Kerrisk
Linux man-pages maintainer; http://www.kernel.org/doc/man-pages/
Linux/UNIX System Programming Training: http://man7.org/training/

[PATCH 0/3] ipc: Further updates to sysv/mqueue limits

[Manfred Spraul]

Hi Andrew,

I got some positive and no negative feedback on my patches, thus:
Could you add the patches to -mm and push them towards Linus?

0001-ipc-msg-increase-MSGMNI-remove-scaling.patch
	- increase MSGMNI to 32000
	- as a bonus, this removes around 300 lines

0002-ipc-sem.c-increase-SEMMSL-SEMMNI-SEMOPM.patch
	- increase all limits
	- update the documentation, it was stale

   Note: Redhat/Oracle recommend values that exceed what I would recommend
   as safe upper limits.
 
https://access.redhat.com/site/documentation/en-US/Red_Hat_Enterprise_Linux/5/html/Tuning_and_Optimizing_Red_Hat_Enterprise_Linux_for_Oracle_9i_and_10g_Databases/sect-Oracle_9i_and_10g_Tuning_Guide-Setting_Semaphores-An_Example_of_Semaphore_Settings.html 

   Unfortunately I didn't get any replies, thus I don't know how to proceed.

   One option would be to switch from kmalloc to ipc_alloc, then the risk of
   failing due to memory fragmentation would be resolved.

0003-ipc-namespace-copy-settings-from-parent-namespace.patch
	Change the namespace code so that a new namespace inherits the values
	from it's parent instead of the boot time defaults.

	Serge Hallyn and Michael Kerrisk also consider the new approach as better.
	One thing that is a bit surprising is that clone(CLONE_NEWIPC)k

I've tested the changes both with unshare -i and with my own test apps.
Unfortunately I didn't manage to get lxc to run on my busybox test setup :-(

--
	Manfred