From mboxrd@z Thu Jan 1 00:00:00 1970 From: Dario Faggioli Subject: [PATCH v3 1/6] xen: sched: fix locking of remove_vcpu() in credit1 Date: Fri, 30 Oct 2015 00:04:13 +0100 Message-ID: <20151029230413.25219.20869.stgit@Solace.station> References: <20151029225158.25219.4625.stgit@Solace.station> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: Received: from mail6.bemta14.messagelabs.com ([193.109.254.103]) by lists.xen.org with esmtp (Exim 4.72) (envelope-from ) id 1ZrwEz-000573-90 for xen-devel@lists.xenproject.org; Thu, 29 Oct 2015 23:04:17 +0000 Received: by wmff134 with SMTP id f134so34708284wmf.0 for ; Thu, 29 Oct 2015 16:04:15 -0700 (PDT) In-Reply-To: <20151029225158.25219.4625.stgit@Solace.station> List-Unsubscribe: , List-Post: List-Help: List-Subscribe: , Sender: xen-devel-bounces@lists.xen.org Errors-To: xen-devel-bounces@lists.xen.org To: xen-devel@lists.xenproject.org Cc: George Dunlap , Andrew Cooper , Jan Beulich List-Id: xen-devel@lists.xenproject.org In fact, csched_vcpu_remove() (i.e., the credit1 implementation of remove_vcpu()) manipulates runqueues, so holding the runqueue lock is necessary. Also, while there, *_lock_irq() (for the private lock) is enough, there is no need to *_lock_irqsave(). Signed-off-by: Dario Faggioli Reviewed-by: Andrew Cooper --- Cc: George Dunlap Cc: Jan Beulich --- Changes from the other series: * split the patch (wrt the original patch, in the original series), and take care, in this one, only of remove_vcpu(); * removed pointless parentheses. --- xen/common/sched_credit.c | 10 +++++++--- 1 file changed, 7 insertions(+), 3 deletions(-) diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c index b8f28fe..6f71e0d 100644 --- a/xen/common/sched_credit.c +++ b/xen/common/sched_credit.c @@ -926,7 +926,7 @@ csched_vcpu_remove(const struct scheduler *ops, struct vcpu *vc) struct csched_private *prv = CSCHED_PRIV(ops); struct csched_vcpu * const svc = CSCHED_VCPU(vc); struct csched_dom * const sdom = svc->sdom; - unsigned long flags; + spinlock_t *lock; SCHED_STAT_CRANK(vcpu_remove); @@ -936,15 +936,19 @@ csched_vcpu_remove(const struct scheduler *ops, struct vcpu *vc) vcpu_unpause(svc->vcpu); } + lock = vcpu_schedule_lock_irq(vc); + if ( __vcpu_on_runq(svc) ) __runq_remove(svc); - spin_lock_irqsave(&(prv->lock), flags); + vcpu_schedule_unlock_irq(lock, vc); + + spin_lock_irq(&prv->lock); if ( !list_empty(&svc->active_vcpu_elem) ) __csched_vcpu_acct_stop_locked(prv, svc); - spin_unlock_irqrestore(&(prv->lock), flags); + spin_unlock_irq(&prv->lock); BUG_ON( sdom == NULL ); BUG_ON( !list_empty(&svc->runq_elem) );