From 4d89dc6ab2711258bfd12c72d753f3ad56b244e2 Mon Sep 17 00:00:00 2001 From: Nadia Derbey Date: Tue, 29 Apr 2008 01:00:40 -0700 Subject: ipc: scale msgmni to the number of ipc namespaces Since all the namespaces see the same amount of memory (the total one) this patch introduces a new variable that counts the ipc namespaces and divides msg_ctlmni by this counter. 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 --- ipc/namespace.c | 3 +++ 1 file changed, 3 insertions(+) (limited to 'ipc/namespace.c') diff --git a/ipc/namespace.c b/ipc/namespace.c index 1b967655eb3..fe3c97aa99d 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -20,6 +20,8 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) if (ns == NULL) return ERR_PTR(-ENOMEM); + atomic_inc(&nr_ipc_ns); + sem_init_ns(ns); msg_init_ns(ns); shm_init_ns(ns); @@ -83,4 +85,5 @@ void free_ipc_ns(struct kref *kref) msg_exit_ns(ns); shm_exit_ns(ns); kfree(ns); + atomic_dec(&nr_ipc_ns); } -- cgit v1.2.3 From b6b337ad1c1d6fe11b09b35d75464b84b3e11f07 Mon Sep 17 00:00:00 2001 From: Nadia Derbey Date: Tue, 29 Apr 2008 01:00:42 -0700 Subject: ipc: recompute msgmni on memory add / remove Introduce the registration of a callback routine that recomputes msg_ctlmni upon memory add / remove. A single notifier block is registered in the hotplug memory chain for all the ipc namespaces. Since the ipc namespaces are not linked together, they have their own notification chain: one notifier_block is defined per ipc namespace. Each time an ipc namespace is created (removed) it registers (unregisters) its notifier block in (from) the ipcns chain. The callback routine registered in the memory chain invokes the ipcns notifier chain with the IPCNS_LOWMEM event. Each callback routine registered in the ipcns namespace, in turn, recomputes msgmni for the owning 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 --- ipc/namespace.c | 11 +++++++++++ 1 file changed, 11 insertions(+) (limited to 'ipc/namespace.c') diff --git a/ipc/namespace.c b/ipc/namespace.c index fe3c97aa99d..f7a35be2e77 100644 --- a/ipc/namespace.c +++ b/ipc/namespace.c @@ -26,6 +26,8 @@ static struct ipc_namespace *clone_ipc_ns(struct ipc_namespace *old_ns) msg_init_ns(ns); shm_init_ns(ns); + register_ipcns_notifier(ns); + kref_init(&ns->kref); return ns; } @@ -81,6 +83,15 @@ void free_ipc_ns(struct kref *kref) struct ipc_namespace *ns; ns = container_of(kref, struct ipc_namespace, kref); + /* + * 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); -- cgit v1.2.3 From e2c284d8a87f95df9b47c6a13168a844ca7c03e9 Mon Sep 17 00:00:00 2001 From: Nadia Derbey Date: Tue, 29 Apr 2008 01:00:44 -0700 Subject: 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 --- ipc/namespace.c | 12 ++++++++++++ 1 file changed, 12 insertions(+) (limited to 'ipc/namespace.c') diff --git a/ipc/namespace.c b/ipc/namespace.c index f7a35be2e77..9171d948751 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); } -- cgit v1.2.3