diff options
| author | San Mehat <san@google.com> | 2010-05-06 15:37:55 -0700 |
|---|---|---|
| committer | Iliyan Malchev <malchev@google.com> | 2011-05-23 15:43:38 -0700 |
| commit | 12dd04d2eb930c5dc519f096b1501cd0346491e3 (patch) | |
| tree | 571a88b1ea3604baaaf1905352ad20eb95d38db0 | |
| parent | 96bc9717a70da31dba573aa89cf16624eefeb880 (diff) | |
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 <san@google.com>
| -rw-r--r-- | include/linux/sched.h | 3 | ||||
| -rw-r--r-- | kernel/fork.c | 16 |
2 files changed, 19 insertions, 0 deletions
diff --git a/include/linux/sched.h b/include/linux/sched.h index 781abd137673..a7dc4032c3b1 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -1724,6 +1724,9 @@ static inline void put_task_struct(struct task_struct *t) extern void task_times(struct task_struct *p, cputime_t *ut, cputime_t *st); extern void thread_group_times(struct task_struct *p, cputime_t *ut, cputime_t *st); +extern int task_free_register(struct notifier_block *n); +extern int task_free_unregister(struct notifier_block *n); + /* * Per process flags */ 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); } |