From 12dd04d2eb930c5dc519f096b1501cd0346491e3 Mon Sep 17 00:00:00 2001 From: San Mehat Date: Thu, 6 May 2010 15:37:55 -0700 Subject: sched: Add a generic notifier when a task struct is about to be freed This patch adds a notifier which can be used by subsystems that may be interested in when a task has completely died and is about to have it's last resource freed. The Android lowmemory killer uses this to determine when a task it has killed has finally given up its goods. Signed-off-by: San Mehat --- kernel/fork.c | 16 ++++++++++++++++ 1 file changed, 16 insertions(+) (limited to 'kernel/fork.c') diff --git a/kernel/fork.c b/kernel/fork.c index e7548dee636b..cc7891831b14 100644 --- a/kernel/fork.c +++ b/kernel/fork.c @@ -155,6 +155,9 @@ struct kmem_cache *vm_area_cachep; /* SLAB cache for mm_struct structures (tsk->mm) */ static struct kmem_cache *mm_cachep; +/* Notifier list called when a task struct is freed */ +static ATOMIC_NOTIFIER_HEAD(task_free_notifier); + static void account_kernel_stack(struct thread_info *ti, int account) { struct zone *zone = page_zone(virt_to_page(ti)); @@ -186,6 +189,18 @@ static inline void put_signal_struct(struct signal_struct *sig) free_signal_struct(sig); } +int task_free_register(struct notifier_block *n) +{ + return atomic_notifier_chain_register(&task_free_notifier, n); +} +EXPORT_SYMBOL(task_free_register); + +int task_free_unregister(struct notifier_block *n) +{ + return atomic_notifier_chain_unregister(&task_free_notifier, n); +} +EXPORT_SYMBOL(task_free_unregister); + void __put_task_struct(struct task_struct *tsk) { WARN_ON(!tsk->exit_state); @@ -196,6 +211,7 @@ void __put_task_struct(struct task_struct *tsk) delayacct_tsk_free(tsk); put_signal_struct(tsk->signal); + atomic_notifier_call_chain(&task_free_notifier, 0, tsk); if (!profile_handoff_task(tsk)) free_task(tsk); } -- cgit v1.2.3