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authorOleg Nesterov <oleg@tv-sign.ru>2006-03-29 04:11:12 +0400
committerLinus Torvalds <torvalds@g5.osdl.org>2006-03-29 06:36:42 +0400
commitaa1757f90bea3f598b6e5d04d922a6a60200f1da (patch)
tree4f8f3804b2595031d0b84de7086dc28375290f0d /fs/exec.c
parent1f09f9749cdde4e69f95d62d96d2e03f50b3353c (diff)
downloadlinux-aa1757f90bea3f598b6e5d04d922a6a60200f1da.tar.xz
[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 <oleg@tv-sign.ru> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
Diffstat (limited to 'fs/exec.c')
-rw-r--r--fs/exec.c3
1 files changed, 1 insertions, 2 deletions
diff --git a/fs/exec.c b/fs/exec.c
index 9046ad2b0614..950ebd43cdc3 100644
--- a/fs/exec.c
+++ b/fs/exec.c
@@ -768,7 +768,6 @@ no_thread_group:
/*
* Move our state over to newsighand and switch it in.
*/
- spin_lock_init(&newsighand->siglock);
atomic_set(&newsighand->count, 1);
memcpy(newsighand->action, oldsighand->action,
sizeof(newsighand->action));
@@ -785,7 +784,7 @@ no_thread_group:
write_unlock_irq(&tasklist_lock);
if (atomic_dec_and_test(&oldsighand->count))
- sighand_free(oldsighand);
+ kmem_cache_free(sighand_cachep, oldsighand);
}
BUG_ON(!thread_group_leader(current));