From: Boris Ostrovsky <boris.ostrovsky@oracle.com>
To: mingo@redhat.com, peterz@infradead.org
Cc: linux-kernel@vger.kernel.org, konrad.wilk@oracle.com,
boris.ostrovsky@oracle.com
Subject: [PATCH] sched/deadline: Test for CPU's presence explicitly
Date: Mon, 17 Feb 2014 09:12:33 -0500
Message-ID: <1392646353-1874-1-git-send-email-boris.ostrovsky@oracle.com> (raw)
A hot-removed CPU may have ID that is numerically larger than the number of
existing CPUs in the system (e.g. we can unplug CPU 4 from a system that
has CPUs 0, 1 and 4).
Thus the WARN_ONs should check whether the CPU in question is currently
present, not whether its ID value is less than num_present_cpus().
Reported-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Signed-off-by: Boris Ostrovsky <boris.ostrovsky@oracle.com>
---
kernel/sched/cpudeadline.c | 6 +++---
1 file changed, 3 insertions(+), 3 deletions(-)
diff --git a/kernel/sched/cpudeadline.c b/kernel/sched/cpudeadline.c
index 045fc74..5b8838b 100644
--- a/kernel/sched/cpudeadline.c
+++ b/kernel/sched/cpudeadline.c
@@ -70,7 +70,7 @@ static void cpudl_heapify(struct cpudl *cp, int idx)
static void cpudl_change_key(struct cpudl *cp, int idx, u64 new_dl)
{
- WARN_ON(idx > num_present_cpus() || idx == IDX_INVALID);
+ WARN_ON(!cpu_present(idx) || idx == IDX_INVALID);
if (dl_time_before(new_dl, cp->elements[idx].dl)) {
cp->elements[idx].dl = new_dl;
@@ -117,7 +117,7 @@ int cpudl_find(struct cpudl *cp, struct task_struct *p,
}
out:
- WARN_ON(best_cpu > num_present_cpus() && best_cpu != -1);
+ WARN_ON(!cpu_present(best_cpu) && best_cpu != -1);
return best_cpu;
}
@@ -137,7 +137,7 @@ void cpudl_set(struct cpudl *cp, int cpu, u64 dl, int is_valid)
int old_idx, new_cpu;
unsigned long flags;
- WARN_ON(cpu > num_present_cpus());
+ WARN_ON(!cpu_present(cpu));
raw_spin_lock_irqsave(&cp->lock, flags);
old_idx = cp->cpu_to_idx[cpu];
--
1.8.1.4
next reply index
Thread overview: 4+ messages / expand[flat|nested] mbox.gz Atom feed top
2014-02-17 14:12 Boris Ostrovsky [this message]
2014-02-17 14:50 ` Peter Zijlstra
2014-02-17 15:49 ` Juri Lelli
2014-02-21 20:32 ` [tip:sched/urgent] sched/deadline: Test for CPU' s " tip-bot for Boris Ostrovsky
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