From mboxrd@z Thu Jan 1 00:00:00 1970 From: Juergen Gross Subject: [PATCH v2 1/2] xen: update timeslice under lock Date: Tue, 2 Feb 2016 12:29:41 +0100 Message-ID: <1454412582-3263-2-git-send-email-jgross@suse.com> References: <1454412582-3263-1-git-send-email-jgross@suse.com> Mime-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <1454412582-3263-1-git-send-email-jgross@suse.com> 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.xen.org, jbeulich@suse.com, alan.robinson@ts.fujitsu.com, george.dunlap@eu.citrix.com, dario.faggioli@citrix.com Cc: Juergen Gross List-Id: xen-devel@lists.xenproject.org When updating the timeslice of the credit scheduler protect the scheduler's private data by it's lock. Today a possible race could result only in some weird scheduling decisions during one timeslice, but further adjustments will need the lock anyway. Signed-off-by: Juergen Gross --- xen/common/sched_credit.c | 5 +++++ 1 file changed, 5 insertions(+) diff --git a/xen/common/sched_credit.c b/xen/common/sched_credit.c index 03fb2c2..8fbbd54 100644 --- a/xen/common/sched_credit.c +++ b/xen/common/sched_credit.c @@ -1101,6 +1101,7 @@ csched_sys_cntl(const struct scheduler *ops, int rc = -EINVAL; xen_sysctl_credit_schedule_t *params = &sc->u.sched_credit; struct csched_private *prv = CSCHED_PRIV(ops); + unsigned long flags; switch ( sc->cmd ) { @@ -1112,8 +1113,12 @@ csched_sys_cntl(const struct scheduler *ops, || params->ratelimit_us < XEN_SYSCTL_SCHED_RATELIMIT_MIN)) || MICROSECS(params->ratelimit_us) > MILLISECS(params->tslice_ms) ) goto out; + + spin_lock_irqsave(&prv->lock, flags); __csched_set_tslice(prv, params->tslice_ms); prv->ratelimit_us = params->ratelimit_us; + spin_unlock_irqrestore(&prv->lock, flags); + /* FALLTHRU */ case XEN_SYSCTL_SCHEDOP_getinfo: params->tslice_ms = prv->tslice_ms; -- 2.6.2