Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753660AbXLIK3w (ORCPT ); Sun, 9 Dec 2007 05:29:52 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1752079AbXLIK3o (ORCPT ); Sun, 9 Dec 2007 05:29:44 -0500 Received: from ebiederm.dsl.xmission.com ([166.70.28.69]:46117 "EHLO ebiederm.dsl.xmission.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751990AbXLIK3n (ORCPT ); Sun, 9 Dec 2007 05:29:43 -0500 From: ebiederm@xmission.com (Eric W. Biederman) To: Oleg Nesterov Cc: Andrew Morton , Davide Libenzi , Pavel Emelyanov , Roland McGrath , Thomas Gleixner , linux-kernel@vger.kernel.org Subject: Re: [PATCH] ITIMER_REAL: convert to use struct pid References: <20071207170336.GA13835@tv-sign.ru> Date: Sun, 09 Dec 2007 03:27:36 -0700 In-Reply-To: <20071207170336.GA13835@tv-sign.ru> (Oleg Nesterov's message of "Fri, 7 Dec 2007 20:03:36 +0300") Message-ID: User-Agent: Gnus/5.110006 (No Gnus v0.6) Emacs/21.4 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 4979 Lines: 130 Oleg Nesterov writes: > signal_struct->tsk points to the ->group_leader and thus we have the nasty code > in de_thread() which has to change it and restart ->real_timer if the leader is > changed. > > Use "struct pid *leader_pid" instead. This also allows us to kill now unneeded > send_group_sig_info(). Acked-by: "Eric W. Biederman" Looks sane to me. > Signed-off-by: Oleg Nesterov > > include/linux/sched.h | 3 +-- > kernel/fork.c | 2 +- > kernel/itimer.c | 2 +- > fs/exec.c | 22 ++-------------------- > kernel/signal.c | 14 -------------- > 5 files changed, 5 insertions(+), 38 deletions(-) > > --- PT/include/linux/sched.h~3_itimer_tsk_pid 2007-12-02 14:53:29.000000000 > +0300 > +++ PT/include/linux/sched.h 2007-12-07 19:24:44.000000000 +0300 > @@ -444,7 +444,7 @@ struct signal_struct { > > /* ITIMER_REAL timer for the process */ > struct hrtimer real_timer; > - struct task_struct *tsk; > + struct pid *leader_pid; > ktime_t it_real_incr; > > /* ITIMER_PROF and ITIMER_VIRTUAL timers for the process */ > @@ -1630,7 +1630,6 @@ extern void block_all_signals(int (*noti > extern void unblock_all_signals(void); > extern void release_task(struct task_struct * p); > extern int send_sig_info(int, struct siginfo *, struct task_struct *); > -extern int send_group_sig_info(int, struct siginfo *, struct task_struct *); > extern int force_sigsegv(int, struct task_struct *); > extern int force_sig_info(int, struct siginfo *, struct task_struct *); > extern int __kill_pgrp_info(int sig, struct siginfo *info, struct pid *pgrp); > --- PT/kernel/fork.c~3_itimer_tsk_pid 2007-12-07 19:03:34.000000000 +0300 > +++ PT/kernel/fork.c 2007-12-07 19:08:57.000000000 +0300 > @@ -882,7 +882,6 @@ static int copy_signal(unsigned long clo > hrtimer_init(&sig->real_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); > sig->it_real_incr.tv64 = 0; > sig->real_timer.function = it_real_fn; > - sig->tsk = tsk; > > sig->it_virt_expires = cputime_zero; > sig->it_virt_incr = cputime_zero; > @@ -1300,6 +1299,7 @@ static struct task_struct *copy_process( > if (clone_flags & CLONE_NEWPID) > p->nsproxy->pid_ns->child_reaper = p; > > + p->signal->leader_pid = pid; > p->signal->tty = current->signal->tty; > set_task_pgrp(p, task_pgrp_nr(current)); > set_task_session(p, task_session_nr(current)); > --- PT/kernel/itimer.c~3_itimer_tsk_pid 2007-10-25 16:22:12.000000000 +0400 > +++ PT/kernel/itimer.c 2007-12-07 19:15:27.000000000 +0300 > @@ -132,7 +132,7 @@ enum hrtimer_restart it_real_fn(struct h > struct signal_struct *sig = > container_of(timer, struct signal_struct, real_timer); > > - send_group_sig_info(SIGALRM, SEND_SIG_PRIV, sig->tsk); > + kill_pid_info(SIGALRM, SEND_SIG_PRIV, sig->leader_pid); > > return HRTIMER_NORESTART; > } > --- PT/fs/exec.c~3_itimer_tsk_pid 2007-12-02 16:07:22.000000000 +0300 > +++ PT/fs/exec.c 2007-12-07 19:18:48.000000000 +0300 > @@ -781,26 +781,8 @@ static int de_thread(struct task_struct > zap_other_threads(tsk); > read_unlock(&tasklist_lock); > > - /* > - * Account for the thread group leader hanging around: > - */ > - count = 1; > - if (!thread_group_leader(tsk)) { > - count = 2; > - /* > - * The SIGALRM timer survives the exec, but needs to point > - * at us as the new group leader now. We have a race with > - * a timer firing now getting the old leader, so we need to > - * synchronize with any firing (by calling del_timer_sync) > - * before we can safely let the old group leader die. > - */ > - sig->tsk = tsk; > - spin_unlock_irq(lock); > - if (hrtimer_cancel(&sig->real_timer)) > - hrtimer_restart(&sig->real_timer); > - spin_lock_irq(lock); > - } > - > + /* Account for the thread group leader hanging around: */ > + count = thread_group_leader(tsk) ? 1 : 2; > sig->notify_count = count; > while (atomic_read(&sig->count) > count) { > __set_current_state(TASK_UNINTERRUPTIBLE); > --- PT/kernel/signal.c~3_itimer_tsk_pid 2007-12-07 17:20:27.000000000 +0300 > +++ PT/kernel/signal.c 2007-12-07 19:23:40.000000000 +0300 > @@ -1204,20 +1204,6 @@ send_sig(int sig, struct task_struct *p, > return send_sig_info(sig, __si_special(priv), p); > } > > -/* > - * This is the entry point for "process-wide" signals. > - * They will go to an appropriate thread in the thread group. > - */ > -int > -send_group_sig_info(int sig, struct siginfo *info, struct task_struct *p) > -{ > - int ret; > - read_lock(&tasklist_lock); > - ret = group_send_sig_info(sig, info, p); > - read_unlock(&tasklist_lock); > - return ret; > -} > - > void > force_sig(int sig, struct task_struct *p) > { -- 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/