On 2015/3/19 18:39, Borislav Petkov wrote:
> On Thu, Mar 19, 2015 at 11:04:30AM +0800, Xie XiuQi wrote:
>> Memory-failure as the high level machine check handler, it's necessary
>> to report memory page recovery action result to user space by ftrace.
>>
>> This patch add a event at ras group for memory-failure.
>>
>> The output like below:
>> # tracer: nop
>> #
>> # entries-in-buffer/entries-written: 2/2 #P:24
>> #
>> # _-----=> irqs-off
>> # / _----=> need-resched
>> # | / _---=> hardirq/softirq
>> # || / _--=> preempt-depth
>> # ||| / delay
>> # TASK-PID CPU# |||| TIMESTAMP FUNCTION
>> # | | | |||| | |
>> mce-inject-13150 [001] .... 277.019359: memory_failure_event: pfn 0x19869: free buddy page recovery: Delayed
>>
>> ---
>> v1->v2:
>> - Comment update
>> - Just passing 'result' instead of 'action_name[result]',
>> suggested by Steve. And hard coded there because trace-cmd
>> and perf do not have a way to process enums.
>>
>> Cc: Tony Luck <tony.luck@xxxxxxxxx>
>> Cc: Steven Rostedt <rostedt@xxxxxxxxxxx>
>> Signed-off-by: Xie XiuQi <xiexiuqi@xxxxxxxxxx>
>> ---
>> include/ras/ras_event.h | 38 ++++++++++++++++++++++++++++++++++++++
>> mm/memory-failure.c | 3 +++
>> 2 files changed, 41 insertions(+)
>>
>> diff --git a/include/ras/ras_event.h b/include/ras/ras_event.h
>> index 79abb9c..ebb05f3 100644
>> --- a/include/ras/ras_event.h
>> +++ b/include/ras/ras_event.h
>> @@ -232,6 +232,44 @@ TRACE_EVENT(aer_event,
>> __print_flags(__entry->status, "|", aer_uncorrectable_errors))
>> );
>>
>> +/*
>> + * memory-failure recovery action result event
>> + *
>> + * unsigned long pfn - Page Number of the corrupted page
>> + * char * action - Recovery action for various type of pages
>> + * int result - Action result
>> + *
>> + * NOTE: 'action' and 'result' are defined at mm/memory-failure.c
>> + */
>> +TRACE_EVENT(memory_failure_event,
>
> What is the real reason for adding this TP? Real-life use cases please.
> Add those to the commit message too.
>
> "Just because" is not a proper justification.
RAS user space tools like rasdaemon which base on trace event, could
receive mce error event, but no memory recovery result event. So, I
want to add this event to make this scenario complete.
I'll add it to commit message, thanks.
>
>> + TP_PROTO(const unsigned long pfn,
>> + const char *action,
>> + const int result),
>> +
>> + TP_ARGS(pfn, action, result),
>> +
>> + TP_STRUCT__entry(
>> + __field(unsigned long, pfn)
>> + __string(action, action)
>> + __field(int, result)
>> + ),
>> +
>> + TP_fast_assign(
>> + __entry->pfn = pfn;
>> + __assign_str(action, action);
>> + __entry->result = result;
>> + ),
>> +
>> + TP_printk("pfn %#lx: %s page recovery: %s",
>> + __entry->pfn,
>> + __get_str(action),
>> + __print_symbolic(__entry->result,
>> + {0, "Ignored"},
>> + {1, "Failed"},
>> + {2, "Delayed"},
>> + {3, "Recovered"})
>
> If you're going to do this, please add a comment above it like this:
>
> /*
> * Keep those in sync with static const char *action_name[] in
> * mm/memory-failure.c
> */
Thanks. I will ;-)
>
> Thanks.
>
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