From e2c284d8a87f95df9b47c6a13168a844ca7c03e9 Mon Sep 17 00:00:00 2001 From: Nadia Derbey Date: Tue, 29 Apr 2008 01:00:44 -0700 Subject: [PATCH] ipc: recompute msgmni on ipc namespace creation/removal Introduce a notification mechanism that aims at recomputing msgmni each time an ipc namespace is created or removed. The ipc namespace notifier chain already defined for memory hotplug management is used for that purpose too. Each time a new ipc namespace is allocated or an existing ipc namespace is removed, the ipcns notifier chain is notified. The callback routine for each registered ipc namespace is then activated in order to recompute msgmni for that namespace. Signed-off-by: Nadia Derbey Cc: Yasunori Goto Cc: Matt Helsley Cc: Mingming Cao Cc: Pierre Peiffer Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/ipc_namespace.h | 25 ++----------------------- ipc/Makefile | 3 +-- ipc/ipcns_notifier.c | 2 ++ ipc/namespace.c | 12 ++++++++++++ 4 files changed, 17 insertions(+), 25 deletions(-) diff --git a/include/linux/ipc_namespace.h b/include/linux/ipc_namespace.h index cfb2a08..c3b1da9 100644 --- a/include/linux/ipc_namespace.h +++ b/include/linux/ipc_namespace.h @@ -4,14 +4,14 @@ #include #include #include -#ifdef CONFIG_MEMORY_HOTPLUG #include -#endif /* CONFIG_MEMORY_HOTPLUG */ /* * 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 @@ -42,9 +42,7 @@ struct ipc_namespace { int shm_ctlmni; int shm_tot; -#ifdef CONFIG_MEMORY_HOTPLUG struct notifier_block ipcns_nb; -#endif }; extern struct ipc_namespace init_ipc_ns; @@ -53,29 +51,10 @@ extern atomic_t nr_ipc_ns; #ifdef CONFIG_SYSVIPC #define INIT_IPC_NS(ns) .ns = &init_ipc_ns, -#ifdef CONFIG_MEMORY_HOTPLUG - extern int register_ipcns_notifier(struct ipc_namespace *); extern int unregister_ipcns_notifier(struct ipc_namespace *); extern int ipcns_notify(unsigned long); -#else /* CONFIG_MEMORY_HOTPLUG */ - -static inline int register_ipcns_notifier(struct ipc_namespace *ipcns) -{ - return 0; -} -static inline int unregister_ipcns_notifier(struct ipc_namespace *ipcns) -{ - return 0; -} -static inline int ipcns_notify(unsigned long ev) -{ - return 0; -} - -#endif /* CONFIG_MEMORY_HOTPLUG */ - #else /* CONFIG_SYSVIPC */ #define INIT_IPC_NS(ns) #endif /* CONFIG_SYSVIPC */ diff --git a/ipc/Makefile b/ipc/Makefile index 388e4d2..65c3843 100644 --- a/ipc/Makefile +++ b/ipc/Makefile @@ -3,8 +3,7 @@ # obj-$(CONFIG_SYSVIPC_COMPAT) += compat.o -obj_mem-$(CONFIG_MEMORY_HOTPLUG) += ipcns_notifier.o -obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o $(obj_mem-y) +obj-$(CONFIG_SYSVIPC) += util.o msgutil.o msg.o sem.o shm.o ipcns_notifier.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/ipcns_notifier.c b/ipc/ipcns_notifier.c index 0786af6..c797460 100644 --- a/ipc/ipcns_notifier.c +++ b/ipc/ipcns_notifier.c @@ -29,6 +29,8 @@ static int ipcns_callback(struct notifier_block *self, switch (action) { case IPCNS_MEMCHANGED: /* amount of lowmem has changed */ + case IPCNS_CREATED: + case IPCNS_REMOVED: /* * It's time to recompute msgmni */ diff --git a/ipc/namespace.c b/ipc/namespace.c index f7a35be..9171d94 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -26,6 +26,12 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_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); kref_init(&ns->kref); @@ -97,4 +103,10 @@ void free_ipc_ns(struct kref *kref) shm_exit_ns(ns); kfree(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); } -- 1.8.2.3