Messages in this thread Patch in this message | | | Date | Mon, 10 Dec 2012 13:35:01 +0100 | From | Ingo Molnar <> | Subject | Re: [PATCH 00/49] Automatic NUMA Balancing v10 |
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hi Srikar,
* Srikar Dronamraju <srikar@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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