hi Srikar,
* Srikar Dronamraju <sri...@linux.vnet.ibm.com> wrote:
> >
> > Either way, last night I applied a patch on top of latest tip/master to
> > remove the nr_cpus_allowed check so that numacore would be enabled again
> > and tested that. In some places it has indeed much improved. In others
> > it is still regressing badly and in two case, it's corrupting memory --
> > specjbb when THP is enabled crashes when running for single or multiple
> > JVMs. It is likely that a zero page is being inserted due to a race with
> > migration and causes the JVM to throw a null pointer exception. Here is
> > the comparison on the rough off-chance you actually read it this time.
>
> I see this failure when running with THP and KSM enabled on
> Friday's Tip master. Not sure if Mel was talking about the same issue.
>
> ------------[ cut here ]------------
> kernel BUG at ../kernel/sched/fair.c:2371!
Could you check whether today's -tip (7ea8701a1a51 or later),
plus the patch below, addresses the crash - while still giving
good NUMA performance?
Thanks,
Ingo
diff --git a/kernel/sched/fair.c b/kernel/sched/fair.c
index 9d11a8a..6a89787 100644
--- a/kernel/sched/fair.c
+++ b/kernel/sched/fair.c
@@ -2351,6 +2351,9 @@ void task_numa_fault(unsigned long addr, int node, int
last_cpupid, int pages, b
int priv;
int idx;
+ if (!p->numa_faults)
+ return;
+
if (last_cpupid != cpu_pid_to_cpupid(-1, -1)) {
/* Did we access it last time around? */
if (last_pid == this_pid) {
--
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