From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753470AbZLIJnM (ORCPT ); Wed, 9 Dec 2009 04:43:12 -0500 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S1753174AbZLIJnL (ORCPT ); Wed, 9 Dec 2009 04:43:11 -0500 Received: from mx1.redhat.com ([209.132.183.28]:34602 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753434AbZLIJnF (ORCPT ); Wed, 9 Dec 2009 04:43:05 -0500 From: Stanislaw Gruszka To: Thomas Gleixner Cc: Ingo Molnar , Oleg Nesterov , Peter Zijlstra , Hidetoshi Seto , Balbir Singh , linux-kernel@vger.kernel.org, Stanislaw Gruszka Subject: [RFC PATCH 5/6] cpu-timers: change arm_timer() locking Date: Wed, 9 Dec 2009 10:39:57 +0100 Message-Id: <1260351598-4203-6-git-send-email-sgruszka@redhat.com> In-Reply-To: <1260351598-4203-5-git-send-email-sgruszka@redhat.com> References: <1260351598-4203-1-git-send-email-sgruszka@redhat.com> <1260351598-4203-2-git-send-email-sgruszka@redhat.com> <1260351598-4203-3-git-send-email-sgruszka@redhat.com> <1260351598-4203-4-git-send-email-sgruszka@redhat.com> <1260351598-4203-5-git-send-email-sgruszka@redhat.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Spread p->sighand->siglock locking scope to assure signal->cputimer is always running when we are setuping signal->cputime_expires. This further assure we do not iterate over all threads in fastpath_timer_check() when calling thread_group_cputimer(). Signed-off-by: Stanislaw Gruszka --- kernel/posix-cpu-timers.c | 14 +++++++------- 1 files changed, 7 insertions(+), 7 deletions(-) diff --git a/kernel/posix-cpu-timers.c b/kernel/posix-cpu-timers.c index 08506ff..68d4045 100644 --- a/kernel/posix-cpu-timers.c +++ b/kernel/posix-cpu-timers.c @@ -549,7 +549,7 @@ static inline int expires_gt(cputime_t expires, cputime_t new_exp) /* * Insert the timer on the appropriate list before any timers that * expire later. This must be called with the tasklist_lock held - * for reading, and interrupts disabled. + * for reading, interrupts disabled and p->sighand->siglock taken. */ static void arm_timer(struct k_itimer *timer) { @@ -568,9 +568,6 @@ static void arm_timer(struct k_itimer *timer) } head += CPUCLOCK_WHICH(timer->it_clock); - BUG_ON(!irqs_disabled()); - spin_lock(&p->sighand->siglock); - listpos = head; list_for_each_entry(next, head, entry) { if (cpu_time_before(timer->it_clock, nt->expires, next->expires)) @@ -605,8 +602,6 @@ static void arm_timer(struct k_itimer *timer) break; } } - - spin_unlock(&p->sighand->siglock); } /* @@ -719,7 +714,6 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, ret = TIMER_RETRY; } else list_del_init(&timer->it.cpu.entry); - spin_unlock(&p->sighand->siglock); /* * We need to sample the current value to convert the new @@ -773,6 +767,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, * disable this firing since we are already reporting * it as an overrun (thanks to bump_cpu_timer above). */ + spin_unlock(&p->sighand->siglock); read_unlock(&tasklist_lock); goto out; } @@ -792,6 +787,7 @@ int posix_cpu_timer_set(struct k_itimer *timer, int flags, arm_timer(timer); } + spin_unlock(&p->sighand->siglock); read_unlock(&tasklist_lock); /* @@ -1201,6 +1197,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) goto out; } read_lock(&tasklist_lock); /* arm_timer needs it. */ + spin_lock(&p->sighand->siglock); } else { read_lock(&tasklist_lock); if (unlikely(p->signal == NULL)) { @@ -1221,6 +1218,7 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) clear_dead_task(timer, now); goto out_unlock; } + spin_lock(&p->sighand->siglock); cpu_timer_sample_group(timer->it_clock, p, &now); bump_cpu_timer(timer, now); /* Leave the tasklist_lock locked for the call below. */ @@ -1229,7 +1227,9 @@ void posix_cpu_timer_schedule(struct k_itimer *timer) /* * Now re-arm for the new expiry time. */ + BUG_ON(!irqs_disabled()); arm_timer(timer); + spin_unlock(&p->sighand->siglock); out_unlock: read_unlock(&tasklist_lock); -- 1.6.2.5