Re: frequent lockups in 3.18rc4
From: Lai Jiangshan
Date: Tue Dec 02 2014 - 21:00:14 EST
On 12/03/2014 12:58 AM, DÃniel Fraga wrote:
> On Tue, 2 Dec 2014 16:40:37 +0800
> Lai Jiangshan <laijs@xxxxxxxxxxxxxx> wrote:
>> It is needed at lest for testing.
>> CONFIG_TREE_PREEMPT_RCU=y with CONFIG_PREEMPT=n is needed for testing too.
>> Please enable them (or enable them under CONFIG_RCU_TRACE=y)
> Lai, sorry but I didn't understand. Do you mean both of them
> enabled? Because how can CONFIG_TREE_PREEMPT_RCU be enabled without
> CONFIG_PREEMPT ?
Sorry, I replied to Paul, and my reply was off-topic, it has nothing
related your reports. Sorry again.
I think we need two combinations for testing (not mainline, but I think
they (combinations) should be enabled for test farms).
So I hope Paul enable them (combinations).
combination1: CONFIG_TREE_PREEMPT_RCU=n & CONFIG_PREEMPT=y
combination2: CONFIG_TREE_PREEMPT_RCU=y & CONFIG_PREEMPT=n
The core code should work correctly in these combinations.
I agree with Paul that these combinations should not be enabled in production,
So my request is: enable these combinations under CONFIG_RCU_TRACE
For myself, I always edit the Kconfig directly, thus it is not a problem
for me. But there is no way for test farms to test these combinations.
> If you mean both enabled, I already reported a call trace with
> both enabled:
> Please see my previous answer to Linus and Paul too.
> Regarding CONFIG_RCU_TRACE, do you mean
> "CONFIG_TREE_RCU_TRACE"? I couldn't find CONFIG_RCU_TRACE.
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