From aa1757f90bea3f598b6e5d04d922a6a60200f1da Mon Sep 17 00:00:00 2001 From: Oleg Nesterov Date: Tue, 28 Mar 2006 16:11:12 -0800 Subject: [PATCH] convert sighand_cache to use SLAB_DESTROY_BY_RCU This patch borrows a clever Hugh's 'struct anon_vma' trick. Without tasklist_lock held we can't trust task->sighand until we locked it and re-checked that it is still the same. But this means we don't need to defer 'kmem_cache_free(sighand)'. We can return the memory to slab immediately, all we need is to be sure that sighand->siglock can't dissapear inside rcu protected section. To do so we need to initialize ->siglock inside ctor function, SLAB_DESTROY_BY_RCU does the rest. Signed-off-by: Oleg Nesterov Signed-off-by: Andrew Morton Signed-off-by: Linus Torvalds --- include/linux/sched.h | 8 -------- 1 file changed, 8 deletions(-) (limited to 'include/linux') diff --git a/include/linux/sched.h b/include/linux/sched.h index ddc0df7f8bf..bbcfc873bd9 100644 --- a/include/linux/sched.h +++ b/include/linux/sched.h @@ -355,16 +355,8 @@ struct sighand_struct { atomic_t count; struct k_sigaction action[_NSIG]; spinlock_t siglock; - struct rcu_head rcu; }; -extern void sighand_free_cb(struct rcu_head *rhp); - -static inline void sighand_free(struct sighand_struct *sp) -{ - call_rcu(&sp->rcu, sighand_free_cb); -} - /* * NOTE! "signal_struct" does not have it's own * locking, because a shared signal_struct always -- cgit v1.2.3