Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S932244AbWCXSfc (ORCPT ); Fri, 24 Mar 2006 13:35:32 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1751357AbWCXSfb (ORCPT ); Fri, 24 Mar 2006 13:35:31 -0500 Received: from iron.cat.pdx.edu ([131.252.208.92]:52188 "EHLO iron.cat.pdx.edu") by vger.kernel.org with ESMTP id S1751144AbWCXSfb (ORCPT ); Fri, 24 Mar 2006 13:35:31 -0500 Date: Fri, 24 Mar 2006 10:34:53 -0800 (PST) From: Suzanne Wood Message-Id: <200603241834.k2OIYrB3006877@baham.cs.pdx.edu> To: akpm@osdl.org, oleg@tv-sign.ru Cc: kiran@scalex86.org, linux-kernel@vger.kernel.org, paulmck@us.ibm.com, suzannew@cs.pdx.edu Subject: Re: [PATCH 2.6.16-mm1] cleanup __exit_signal->cleanup_sighand path Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 3090 Lines: 80 Thank you. This looks good. It clarifies the setting of tsk->sighand to NULL before releasing siglock as you suggested earlier on LKML. And it addresses all the occurrences in the mm-kernel of cleanup_sighand() to become __cleanup_sighand() with the different argument -- paralleling the __cleanup_signal(). The patch draws attention to __exit_signal() of fork.c and when the decremented sig->count doesn't go to zero, the 'else' branch of the conditional, after incrementing several counter fields of sig, sets sig to NULL to morph it into a flag -- interesting. Thanks. Suzanne > From Oleg Nesterov Thu Mar 23 10:59:36 2006 > This patch moves 'tsk->sighand = NULL' from cleanup_sighand() to > __exit_signal(). This makes the exit path more understandable and > allows us to do cleanup_sighand() outside of ->siglock protected > section. > Signed-off-by: Oleg Nesterov > --- MM/include/linux/sched.h~1_ESCS 2006-03-23 22:48:10.000000000 +0300 > +++ MM/include/linux/sched.h 2006-03-23 23:00:02.000000000 +0300 > @@ -1184,7 +1184,7 @@ extern void exit_thread(void); > > extern void exit_files(struct task_struct *); > extern void __cleanup_signal(struct signal_struct *); > -extern void cleanup_sighand(struct task_struct *); > +extern void __cleanup_sighand(struct sighand_struct *); > extern void exit_itimers(struct signal_struct *); > > extern NORET_TYPE void do_group_exit(int); > --- MM/kernel/fork.c~1_ESCS 2006-03-23 22:48:10.000000000 +0300 > +++ MM/kernel/fork.c 2006-03-23 22:59:33.000000000 +0300 > @@ -808,12 +808,8 @@ static inline int copy_sighand(unsigned > return 0; > } > > -void cleanup_sighand(struct task_struct *tsk) > +void __cleanup_sighand(struct sighand_struct *sighand) > { > - struct sighand_struct * sighand = tsk->sighand; > - > - /* Ok, we're done with the signal handlers */ > - tsk->sighand = NULL; > if (atomic_dec_and_test(&sighand->count)) > kmem_cache_free(sighand_cachep, sighand); > } > @@ -1232,7 +1228,7 @@ bad_fork_cleanup_mm: > bad_fork_cleanup_signal: > cleanup_signal(p); > bad_fork_cleanup_sighand: > - cleanup_sighand(p); > + __cleanup_sighand(p->sighand); > bad_fork_cleanup_fs: > exit_fs(p); /* blocking */ > bad_fork_cleanup_files: > --- MM/kernel/exit.c~1_ESCS 2006-03-23 22:48:10.000000000 +0300 > +++ MM/kernel/exit.c 2006-03-23 23:02:53.000000000 +0300 > @@ -114,10 +114,11 @@ static void __exit_signal(struct task_st > __unhash_process(tsk); > > tsk->signal = NULL; > - cleanup_sighand(tsk); > + tsk->sighand = NULL; > spin_unlock(&sighand->siglock); > rcu_read_unlock(); > > + __cleanup_sighand(sighand); > clear_tsk_thread_flag(tsk,TIF_SIGPENDING); > flush_sigqueue(&tsk->pending); > if (sig) { - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/