Re: [PATCH V8] Eliminate task stack trace duplication

[Ying Han]

++cc x86 people which I forgot this time ..

--Ying

On Fri, Apr 6, 2012 at 11:57 AM, Rik van Riel <riel@xxxxxxxxxx> wrote:
> On 04/06/2012 02:45 PM, Ying Han wrote:
>>
>> The problem with small dmesg ring buffer like 512k is that only limited
>> number
>> of task traces will be logged. Sometimes we lose important information
>> only
>> because of too many duplicated stack traces. This problem occurs when
>> dumping
>> lots of stacks in a single operation, such as sysrq-T.
>>
>> This patch tries to reduce the duplication of task stack trace in the dump
>> message by hashing the task stack. The hashtable is a 32k pre-allocated
>> buffer
>> during bootup. Each time if we find the identical task trace in the task
>> stack,
>> we dump only the pid of the task which has the task trace dumped. So it is
>> easy
>> to back track to the full stack with the pid.
>
>
>> Signed-off-by: Ying Han<yinghan@xxxxxxxxxx>
>
>
> Acked-by: Rik van Riel <riel@xxxxxxxxxx>
>
> --
> All rights reversed
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