From: Dario Faggioli <dario.faggioli@citrix.com>
To: xen-devel@lists.xenproject.org
Cc: Andrew Cooper <andrew.cooper3@citrix.com>,
Anshul Makkar <anshul.makkar@citrix.com>,
George Dunlap <george.dunlap@citrix.com>
Subject: [PATCH v2 2/2] xen: credit2: fix potential issues in csched2_cpu_pick with tracing enabled
Date: Tue, 19 Jul 2016 17:34:04 +0200 [thread overview]
Message-ID: <146894244486.483.13984277930071960202.stgit@Solace.fritz.box> (raw)
In-Reply-To: <146894226840.483.8554580913887484141.stgit@Solace.fritz.box>
In fact, when not finding a suitable runqueue where to
place a vCPU, and hence using a fallback, we either:
- don't issue any trace record (while we should),
- risk underruning when accessing the runqueues
array, while preparing the trace record.
Fix both issues and, while there, also a couple of style
problems found nearby.
Spotted by Coverity.
Signed-off-by: Dario Faggioli <dario.faggioli@citrix.com>
Reported-by: Andrew Cooper <andrew.cooper3@citrix.com>
---
Cc: George Dunlap <george.dunlap@citrix.com>
Cc: Anshul Makkar <anshul.makkar@citrix.com>
---
Changes from v1:
* cite Coverity in the changelog.
---
xen/common/sched_credit2.c | 13 +++++++------
1 file changed, 7 insertions(+), 6 deletions(-)
diff --git a/xen/common/sched_credit2.c b/xen/common/sched_credit2.c
index a55240f..3009ff9 100644
--- a/xen/common/sched_credit2.c
+++ b/xen/common/sched_credit2.c
@@ -1443,7 +1443,8 @@ csched2_cpu_pick(const struct scheduler *ops, struct vcpu *vc)
{
/* We may be here because someone requested us to migrate. */
__clear_bit(__CSFLAG_runq_migrate_request, &svc->flags);
- return get_fallback_cpu(svc);
+ new_cpu = get_fallback_cpu(svc);
+ goto out;
}
/* First check to see if we're here because someone else suggested a place
@@ -1505,7 +1506,7 @@ csched2_cpu_pick(const struct scheduler *ops, struct vcpu *vc)
if ( rqd_avgload < min_avgload )
{
min_avgload = rqd_avgload;
- min_rqi=i;
+ min_rqi = i;
}
}
@@ -1520,20 +1521,20 @@ csched2_cpu_pick(const struct scheduler *ops, struct vcpu *vc)
BUG_ON(new_cpu >= nr_cpu_ids);
}
-out_up:
+ out_up:
read_unlock(&prv->lock);
-
+ out:
if ( unlikely(tb_init_done) )
{
struct {
uint64_t b_avgload;
unsigned vcpu:16, dom:16;
unsigned rq_id:16, new_cpu:16;
- } d;
- d.b_avgload = prv->rqd[min_rqi].b_avgload;
+ } d;
d.dom = vc->domain->domain_id;
d.vcpu = vc->vcpu_id;
d.rq_id = c2r(ops, new_cpu);
+ d.b_avgload = prv->rqd[d.rq_id].b_avgload;
d.new_cpu = new_cpu;
__trace_var(TRC_CSCHED2_PICKED_CPU, 1,
sizeof(d),
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next prev parent reply other threads:[~2016-07-19 15:34 UTC|newest]
Thread overview: 5+ messages / expand[flat|nested] mbox.gz Atom feed top
2016-07-19 15:33 [PATCH v2 0/2] xen: Credit2: fix two issues from recently committed series Dario Faggioli
2016-07-19 15:33 ` [PATCH v2 1/2] xen: credit2: fix two s_time_t handling issues in load balancing Dario Faggioli
2016-07-20 9:33 ` George Dunlap
2016-07-19 15:34 ` Dario Faggioli [this message]
2016-07-20 9:47 ` [PATCH v2 2/2] xen: credit2: fix potential issues in csched2_cpu_pick with tracing enabled George Dunlap
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